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NFPA 70®

National Electrical Code® 2020 Edition This edition of NFPA 70, National Electrical Code, was prepared by the National Electrical Code Committee and acted on by NFPA at itsJtme Association Technical Meeting held June 17-20, 2019, in San Antonio, TX. It was issued by the Standards Council on August 5, 2019, with an effective date of August 25, 2019, and supet·sedes all previous editions. This Code was issued with Tentative Interim Amendments (TlAs) that impacted provisions in 210.52(C) (2), 240 .67(C), 240.87(C), 725.1 21 (C), and Annex D3. For more information on TIA~. see www.nfpa.org/70 and Section 5 of the Regulations Governing the Development of NFPA Standards available at www.nfpa.org/ regs. This edition of NFPA 70was approved as an American National Standard on August 25, 2019. History and Development of the National Electrical Code® The National Fire Protection Association has acted as sponsor of the National Electrical Code sin ce 1911. The original Code do cumen twas developed in 1897 as a result of the united efforts of various insurance, electrical , architectural, and allied interests. ln accordance with the Regulations Governing the Development of NFPA Standards, a National Electrical Code first draft report containing proposed amendments to the 2017 National fiectrical Code was published by NFPA in July 2018. This t·eport recorded the actions of the various code-making panels and the correlating committee of the National Electr ical Code Committee on each public input and first revision that had been made to revise the 2017 Cocle. The report was published at www.nfpa.org/70. Following the close of the public comment period, the code-making panels met, acted on each comment, and created some second revisions, which were reported to the correlating committee. NFPA published the NationalJ!,'lechical Code second draft report in April 2019, which recorded the actions of the code-making panels and the correlating corrunittee on each public comment on the National Electrical Code Committee first draft report. The National Elect1ical Code first draft report and the NationalElect1ical Code second draft report were presented to the 2019 June Association Technical Meeting for adoption . NFPA has an Electrical Section that provides particular opportunity for NFPA members interested in electrical safety to become better informed and to contribute to the development of the National Electrical Code and other NFPA electrical standards. At the Elecu·ical Section codes and standards review session held at the 2019 NFPA Conference and Expo, section members had the opportunity to discuss and review the report of the National Elecu·ical Code Committee prior to the adoption of this edition of the Code by the association at its 2019 Jun e Technical Meeting. This 55th edition supersedes all other previous editions, supplements, and printings dated 1897, 1899, 1901, 1903, 1904, 1905, 1907, 1909,1911, 191 3, 1915, 1918, 1920, 1923, 1925, 1926, 1928, 1930, 1931, 1933, 1935, 1937, 1940, 1942, 1943, 1947, 1949, 1951, 1953, 1954, 1955, 1956, 1957, 1958, 1959, 1962,1965, 1968, 1971, 1975,1978, 1981, 1984, 1987, 1990, 1993, 1996, 1999,2002,2005,2008,2011, 2014, and 2017. This Code is purely advisory as far as NFPA is concerned. It is made available for a wide variety of both public and private uses in the interest of life and property protection . These include both use in law and for regulatory purposes and use in private self~regulation and standardization activities such as insurnnce underwriting, building and facilities construction and management, and product testing and certification.

NFPA 70, National Electrical Code, NFPA and National Fire Protection Association are registered trademarks of the National Fire Protection Association, Quincy, Ma.o;.,achusetts 02169.

NATIONAL ELECTRICAL CODE

Contents 90

In troduction ......................................................... 70-

29

Chapter 1 General 100 Part I. Part II. Part Ill. llO Part I. Part II. Part Ill. Part IV. Part \I.

Definitions ........................................................... . General ................................................................. O ver 1000 Volts, Nominal ................................... . Hazardous (Classified) Locations (CMP-14) ... . Requirement~ for Electrical Installations ........... General ................................................................. 1000 Volts, Nominal, or Less .............................. . O ver 1000 Volts, Nominal ................................... . Tunnel Installations over 1000 Volts, Nominal .. Manholes and Other Electrical Enclosures Intended for Personnel Entry .............................

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32 32 41 42 46 46 50 52

55

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56

Chapter 2 Wiring and Protection Use and Identification of Ground ed Conductors ................................................... ........ Branch Circuits .......................... ......................... . 210 Part I. General Provisions .............................. ................ . Part II. Branch-Circuit Ratings ..................... .................. . Part Ill. Required Oudets ................................................. . 215 Feeders ................................................................. . Branch-Circuit, Feeder, and Service Load 220 Calculations ......................................................... . Part I. General ................................................................ . Part II. Branch-Circuit Load Calculations ................. ..... . Part Ill. Feeder and Service Load Calcu lations .............. . Part IV. Optional Feeder and Service Load Calculations .................................................. ....... . Part \I. Farm Load Calcu lations ...................................... . Outside Branch Circuits and Feeders ................ . 225 Part I. General ................................................................ . Part II. Buildings or Od1e r Strucnires Supplied by a Feeder (s) or Branch Circuit(s) .......................... . Part Ill. Over 1000 Volts.. ................................... .......... ..... 230 Services .................................................. .......... ..... Part I. General ................................................... .......... ... . O verhead Service Conductors ..................... ....... . Part II. Part Ill. Unde rground Service Conductors .............. ....... . Service-Entrance Conductors ....................... ...... . Part IV. Part \I. Service Equipment - General ........ .................. . Service Equipment - D isconnecting Means .... . Part VI. Part VII. Service Equipment - Overcurrent P rotection .. Part VIII. Services Exceeding 1000 Volts, Nominal ........... . O vercurrent Protection ....................................... 240 Part I. General ........................................................ ......... Location ........................................... ..... ............... . Part II. Part Ill. Enclosures ....................................... .......... ..... ..... . Disconnecting and Guarding .............................. Part IV. Part \I. Plug Fuses, Fuseholders, and Adapters .......... ... . Part VI. Cartridge Fuses and Fuseholders ........................ Part VII. Circ uit Breakers ........................................ ..... ..... . Part VIII. Supervised Industrial Installations ...................... Part IX. O vercurrent Protection over 1000 Volts, Nominal ................................................................ 242 O vervoltage Protection ................................. ...... . Part I. General ................................................................. Part II. Surge-Protective Devices (SPDs), 1000 Volts or Less ....................................................................... Part Ill. Surge Arresters, O ver 1000 Volts ................. ....... . 250 Grounding and Bonding .................................... . Part I. Gene ral ......................................... ............... ......... Part II. System Grounding ...... .............................. ..... ..... .

Part IU .

Grounding Electrode System and Ground ing Electrode Conductor.. ......................................... Part IV. Enclosure, Raceway, and Service Cable Connections ......................................................... Bonding ............................... ................................. Part\/. Equipment Grounding and Equipment Part VI. Grounding Conductors....................................... Part VII. Methods of Equipment Grounding Conductor Connections..................................... ............... ..... Part \/Ill . Direct-Current Systems ....... ................................. Part IX. Instrume nts, Meters, and Re lays ...... ................... Part X. Grounding of Systems and Circ uits of over 1000 Volts .......... ............................................. ......

300

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58 60 60 65 68 71

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73 73 74 76

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79 81 82 82

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85 86 88 88 89 90 91 93 93 95 96 97 97 IOI 104 104 104 104 105 107

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109 l lO 111 Ill 113

70- 125 70- 125 70- 129 70- 133 70- 135 70- 136 70- 137

Chapter 3 Wiring Methods and Materials

200

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70- 120

Part I. Part II . 310 Part I. Part II . Part Ill. 3ll Part I. P art II . P art Ill. P art 1\1. 312 P art I. P art II . 314

P art I. P art II . P art Ill. P art 1\1.

320 P art I. P art II . P art Ill. 322 P art I. P art II . P art Ill. 324 P art I. P art II . P art Ill. 326 P art I. P art II . P art Ill. 330 Part l. Part II. Part 111. 332 Part l. Part II.

General Requirements for Wiring Me mods and Materials............................................................... General Requirements ..................... .................... Requirements for over 1000 Volts, Nominal ...... Conducrors for Ge neral Wiring .......................... General .... ..... ..... ..... .......... ..... .......... ..... ..... ........... Construction Specifications .......................... ...... Installation ................. ........................................... Medium Voltage Conductors and Cable.. .......... General ................................................................. Consm1ction Specifications ........... ............... ...... Installation .................................................... ........ Ampacities ............................................................ Cabinets, Cutout Boxes, and Meter Socket Enclosures.. .......................................................... Scope and Installation ....... .................................. Consm1ction Specifications................................ Oudet, Device, Pu ll, and j unc tion Boxes; Conduit Bodies; Fittings; and Handho le Enclosures.. ......................... ................................. Scope and General ........................ ....................... Installation .................................................... ........ Consm1ction Specifications ................................ Pu ll and j unction Boxes, Conduit Bodies, and Handhole Enclosures for Use on Systems over 1000 Volts, Nominal ................ ............................. Armo red Cable: Type AC .............. ....................... General ........................................................... ...... Installation ............................................................ Consm1ction Specifications ................................ Flat Cable Assemblies: Type FC ........................... General ........................................................... ...... Installation ............................................................ Consm1ction Specifications ................................ Flat Conductor Cable: Type FCC ........................ General ........................................................... ...... Installation ............................................... ............. Consm1ction Specifications ..................... ........... Integrated Gas Spacer Cable: Type l GS .............. General .................................. ............... .......... ...... Installation ............................................... ............. Consm1ction Specifications ...... ............... ........... Metal-Clad Cable: Type MC ................... ..... ......... General ................................................................. Installation ............................................................ Construction Specifications ................................ Mineral-Insulated , Metal-Sheathed Cable: Type Ml .......................................................................... General ............................. .................................... Installation .......................................... ..................

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140 140 149 15 1 15 1 15 1 156 165 165 165 167 168

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182 182 183 189

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189 190 190 190 191 191 191 192 192 192 192 193 194 194 194 194 195 195 195 195 197

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2020 Edi tion

CONTENTS

Part Ill. 334 Part !. Part II. Part Ill.

336 Part !. Part II. Part Ill. 337 Part !. Part II. Part Ill. 338 Part !. Part II. Part Ill. 340 Part !. Part II. Part Ill.

342 Part !. Part II. Part Ill.

344 Part I. Part II. Part Il l.

348 Part I. Part II.

350 Part I. Part II. Part Il l.

352 Part I. Part II. Part Il l. 353 Part I. Part II. Part Ill.

354 Part I. Part II. Part Ill.

355 Part I. Part II. Part Ill.

356 Part I. Part II. Part Ill.

358 Part I. Part ll. Part III.

2020 Edition

Construction Specifications ................................ Nonmetallic-Sh eathed Cable: Types NM and NMC ............................. ......................................... General ...... ........................................................... Installation ................... ......................................... Construction Specifications ................................ Power and Control Tray Cable: Type T C........... . General . ..... ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... .... Installation ................... ......................................... Construction Specifications ................................ Type P Cable ....................... ..... ............................. General . ..... ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... .... Installation ................... ......................................... Construction Specifications ................................ Setv ice-Entrance Cable: Types SE and USE....... General . ..... ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... .... Installation ................... ......................................... Construction Specifications ................................ Underground Feeder and Branch-Circuit Cable: Type UF ... .............................. ..... .......... ..... General . ..... ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... .... Installation ................... ......................................... Construction Specifications ................................ Intermediate Metal Conduit: Type IMC ............. General . ..... ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... .... Installation ................... ......................................... Construction Specifications ................................ Rigid Metal Condui t: Type RMC ......................... General . ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... .......... .... Installation ............................. .......... .......... ..... ..... . Construction Specifications ............. ..... ..... ......... Flexible Metal Conduit: Type F MC ...... ..... ..... ..... General . ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... .......... .... Installation ............................. .......... ............... ..... . Liquid tight Flexible Metal Conduit: Type LFMC .............. ..... .......... ............... ..... ................... General . ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... .......... .... Installation ....................................... ............... ..... . Construction Specifications ............. ..... .............. Rigid Po lyvinyl Chloride Conduit: Type PVC ..... General ........... ............... ............... ..... ................... Installation ....................................... ............... ..... . Construction Specifications ............. ..... .............. H igh Density Po lyeth ylene Conduit: Type HOPE Conduit .............. ............... ..... ................... General ........... ............... .......... ..... ..... ................... Installation ...................................................... ..... . Construction Specifications ............. ..... .............. Nonmetallic Underground Conduit with Conductors: Type NUCC .............................. ....... General ........... ............... .......... ..... ..... ..... .............. Installation ....................................... ............... ..... . Construction Specifications ............. ..... .............. Reinforced Thermosetting Resin Conduit: Type RTRC ........... ............... ..... ...................................... General ........... ............... .......... ..... ..... ..... .............. Installation ....................................... ............... ..... . Construction Specifications ............. ..... .............. Liquidtight Flexible Non metallic Conduit: Type LFNC ........... ............... ..... ...................................... General ........... ............... .......... ..... ..... ..... .............. Installation .................................. ..... .......... ..... ..... . Construction Specifications ............. ..... ..... ......... Electrical Metallic Tubing: Type El\IIT ................ General ......................................... ........................ Installation .................................. .................... ...... Constructio n Specifications............. .......... .........

NATIONAL ELECTRICAL CODE

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198 198 198 200 200 200 200 201 202 202 202 202 202 202 203 203

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204 204 204 204 204 204 204 206 206 206 206 207 207 207 208

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209 209 209 210 210 210 210 212

360 Part I. Part 11. Part II I. 362 Part I. Part 11. Part II I. 366 Part I. Part 11. Part II I. 368 Part I. Part 11. Part II I. Part IV. 370 Part I. Part II. Part II I. 372 Part I. Part II. 374 Part I. Part II . Part II I. 376 Part I. Part II . Part II I. 378 Part I. Part II . Part II I. 380 Part I. Part II . 382 Part I. Part II . Part II I.

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212 212 213 213

384 Part I. Part II . Part II I.

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213 213 214 214

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215 215 215 216

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217 217 217 218 218 218 218 219

386 Part I. Part II . Part lI I. 388 Part I. Part II. Part lI I. 390 Part I. Part II. 392 Part I. Part II. Part lI I. 393 Part I. Part II.

Flexib le Metallic Tubing: Type FMT ................... General .... .............................. ..... .......... ................ Installation ................. ............... ............................ Construction Specifications..................... ........... Electrical Nonmetallic Tubing: Type ENT ......... General .... ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... ...... Installation ................. ........................................... Construction Specifications ................................ AlLxiliary Gutters ................... ..... .......................... General .... ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... ...... Installation ................. ........................................... Construction Specifications ................................ Busways . ..... ..... ..... ..... ..... ..... ..... ..... ..... .......... ..... .... General Requirements ......................................... Installation ................. ........................................... Construction ..................................... .................... Requ irement.~ for Over 1000 Volts, Nominal .... . Cable bus ......... ..... .......... ............... ........................ General .... ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... ..... . Installation ................. ........................................... Construction Specifications ................................ Cellu lar Concrete Floor Raceways ...................... General .... ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... ..... . Installations ........... ................................... .......... .. Cellular Metal Floor Raceways ....................... ..... General .... ..... ..... ..... ..... ..... ..... ..... ..... ..... .......... ...... Installation ........................... .......... .......... ..... ..... ... Construction Specifications ........... ..... ................ Metal Wireways .... ......................... ..... ..... ..... ......... General .... ..... ..... ..... ..... ..... ..... ..... ..... ..... .......... ...... Installation ........................... .......... .......... ..... ..... ... Construction Specifications ........... ..... ................ Non metallic Wireways .. .............................. .......... General .... ..... ..... ..... ..... ..... ..... ..... ..... ..... .......... ...... Installation ........................... .......... .......... ..... ..... ... Construction Specifications ........... ..... ................ Mu ltioutlet Assembly ........ ..... .............................. General .... ..... ............... .......... ..... ..... .................... . Installation ................. ............... ..... .......... ..... ..... ... Non metallic Extensions ........ ..... .......................... General .... ..... ..... ..... ..... ..... ..... ..... ..... ..... .......... ..... . Installation ................. .................... ............... ..... ... Construction Specifications (Concealable Non metallic Extensions Only) ........... ..... ............ Strut-Type C hannel Raceway ........ ..... .......... ..... ... General .... ..... ..... ..... ..... ..... ..... ..... ..... ..... .......... ..... . Installation ................. .................... .......... ..... ..... ... Construction Specifications ........... ..... ................ Surface Metal Raceways ...... .......... ..... .......... ..... ... General .... ..... ..... ..... ..... ..... ..... ..... ..... ..... .......... ..... . Installation ................. .................... .......... ..... ..... ... Construction Specifications........... .......... ........... Surface Nonmetallic Race1"'1ys ................... ......... General .... ............... ..... ..... ..... ..... ..... ..... ..... ..... ...... Installation .. .................................................. ........ Construction Specifications........... .......... ........... Under floor Raceways ... ........................................ General .... ............... ..... ..... .......... ..... ..... ..... ..... ...... Installation .. .............................. .................... ........ Cable Trays ............... ................................... ......... General ................... ..... ............... ..... ..... ................ Installation .................................................... ........ Construction Specifications........... ..................... Low-Voltage Suspended Ceiling Power Distribution Systems ............................................ General .... ............... ..... ..... .......... ..... ..... ..... ..... ...... Installation .................................................... ........

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219 219 220 220 220 220 221 222 222 222 222 223 224 224 224 225 225 226 226 226 227 227 227 227 228 228 228 229 229 229 229 230 230 230 230 231 231 231 231 232 232 232

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233 233 233 233 234 234 234 234 235 235 235 235 236 236 236 236 237 237 237 243

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NATIONAL ELECTRICAL CODE

Part Ill.

394 Part I. Part IL Part Ill.

396 Part I. Part IL

398 Part I. Part IL Part Ill.

399

Construction Specifications ........ ............... ........ . Concealed Knol:>-and-Tube Wiring ......... ........... . General .................................... ............... .............. Installation .... ........................................ ..... .......... . Construction Specifications ........ .......... ..... ........ . Messenger-Supported Wiring ...................... ....... . General .................................... ............... .............. Installation .... ........................................ ..... .......... . Open Wiring on Insulators ......... .......... ..... ........ . General .................................... .......... ..... .............. Installation .... ........................................ ..... .......... . Construction Specifications ........ ............... ........ . Outdoor Overhead Conductors over 1000 Volts ..................................... ............... ........ .

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245 246 246 246 246 247 247 247 247 247 248 249

406 408 Part I. Part II. Part Ill. Part IV.

409 Part I. Part II. Part Ill. 410 Part I. Part II. Part Ill. Part IV. Part V. Part VI. Part VIL Part VIII. Part IX. Part X. Part XL Part XII. Part XIII. Part XIV. Part XV. Part XVI. 4 ll

422 Part I. Part II. Part Ill. Part IV. Part V. 424 Part I.

70-4

Flexible Cords and Flexible Cables ..................... General . ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... .... Construction Specifications................................ Portable Cables Over 600 Volts, Nominal .......... Fixture Wires ........................................................ s"~ tches ... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ...... Installation ............................................................ Construction Specifications................................ Receptacles, Cord Connectors, and Attachment Plugs (Caps) ......................................................... S"~tchboards, Switchgear, and Panelboards ...... General . .......... ..... .......... ..... ..... .......... ..... ..... ..... .... S"~tchboards and Switchgear .............................. Panelboards ... .......... ..... .......... ..... ..... .......... ..... ..... Construction Specifications................................ Industrial Control Panels ......................... ........... General . .......... ..... .......... ..... ..... .......... ..... ..... ..... .... Installation ............................................................ Construction Specifications................................ L uminaires, Lampholders, and Lamps ............... General . .......... ..... .......... ..... ..... .......... ..... ..... ..... .... L uminaire Locations ...... ...................................... Provisions at Luminaire Outlet Boxes, Canopies, and Pans.............................................. L uminaire Support5 ............................................. Grounding .............................. .............................. Wiring of L uminaires ....... .................................... Construction of Luminaires ............. ................... i nstallation of Lamphoklers ................................ Lamps and Auxiliary Equipment ........................ Special Provisions for Flush and Recessed L uminaires ....................................................... .... Construction of Flush and Recessed L uminaires ....................................................... .... Special Provisions for Electric-Discharge Lighting Systems of 1000 Volts or Less ............... Special Provisions for Electric-Discharge Lighting Systems of More Than 1000 Volts ........ Lighting Track ....................... ............................... Decorative Lighting and Similar Accessories ..... Special Provisions for Horticultural Lighting Equipment ............................................................ Low-Voltage Lighting ...... ..... ................................ Appliances ........ ..... ..... ..... ..... ..... ............... ..... ....... General ...... .......... ..... ..... ..... .......... ..... ..... ..... ......... i nstallation ............................................ ................ Disconnecting Means ............... ..... ....................... Construction ............................. ..... ....................... Marking ....................... ................................... ...... Fixed Electric Space-Heating Equipment.... ...... General ........................................................ .........

Part IV. Part V. Part VI. Part VII. Part VIII. Part IX. Part X.

425 70- 249

Chapter 4 Equipment for General Use 400 Part I. Part II. Part Ill. 402 404 Part I. Part II.

Part IL Part Ill.

7070707070707070-

2.50 2.50 2.59 260 260 263 263 266

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266 271 271 273 273 274 275 275 275 276 277 277 278

70707070707070-

279 279 280 280 282 282 282

Part I. Part IL Part Ill. Part IV. Part V. Part VI. Part VIL 426 Part I. Part IL Part Ill. Part IV. Part V. Part VI. 427 Part I. Part IL Part Ill. Part IV. Part V. Part VI. Part VIL

430 Part I. Part IL Part Ill. Part IV. Part V.

70- 282 70- 283 70- 283 70- 284 70- 285 70- 285 70707070707070707070-

285 286 286 286 287 289 290 291 291 291

Part VI. Part VIL Part VIII . Part IX. Part X. Part XL Part XII. Part XIII . Part XIV. 440 Part I. Part IL Part Ill. Part IV. Part V. Part VI. Part VIL

Installation .. .......................................................... Control and Protection of Fixed Electric SpaceHeating Equipment...... ....................................... Marking of Heating Equipment .......................... Electric Space-Heating Cables ............................. Duct Heaters ..... ................................................... Resistance-Type Boilers ........................................ Electrode-Type Boilers ......................................... Electric Radiant Heating Panels and Heating Panel Set5 .... ..... ............... ..... ..... ......................... ... Low-Vo ltage Fixed Electric Space-Heating Equipment ............................................................ Fixed Resistance and Electrode l ndu5trial Process Heating Equipment ................................ General .... ..... ..... ..... ......................... ..... ..... ..... ...... Installation ............................................................ Control and Protection of Fixed Industrial Process Heating Equipment ................................ Marking of Heating Equipment .......................... Fixed Industrial Process Duct Heaters ............... Fixed Industrial Process Resistance-Type Boilers .. ..... ......................... ..... ..... ............... ..... ..... Fixed Industrial Process Electrode-Type Boilers Fixed Outdoor Electric Deicing and SnowMelting Equipment .............................................. General .... ..... ..... ..... .......... ............... ..... ..... ..... ...... Installation ............................................................ Resistance Heating Elements .............................. impedance Heating ............................................. Skin-Effect Heating.............................................. Control and Protection ....................................... Fixed Electric Heating Equipment for Pipelines and Vessels ............. ..... ..... ......................... ..... ....... General .... ..... ..... ..... .......... ............... ..... ..... ..... ...... Installation ............................................................ Resistance Heating Elements .............................. impedance Heating ............................................. Induction Heating............................................... Skin-Effect Heating.................................... .......... Control and Protection ....................................... Motors, Motor Circuits, and Controllers ............ General .... .......... ..... ..... ..... ..... ..... .......... .......... ...... Motor Circuit Conductors ................................... Motor and Branch-Circuit O verload Protection Motor Branch-Circuit Short-Circuit and Ground-Fault Protection ..................................... Motor Feeder Short-Circuit and Ground-Fault Protection ............................................................ . Motor Contro l Circuit5 .................................. ..... . Motor Contro llers .......................................... ..... . Motor Contro l Centers .................................. ..... . Disconnecting Means ................................. ..... .... . Adjustable-Speed Drive Systems ......................... . Over 1000 Volts, Nominal ................................... . Protection of Live Parts - All Voltages ............. . Grounding - All Voltages ................................. . Tables ................................................................... . Air-Conditioning and Refrigerating Equipment General ................................................................ . Disconnecting Means ...................................... .... . Branch-Circuit Short-Circuit and Ground-Fault Protection ..................... ........................................ Branch-Circuit Conductors................................. Controllers for Motor-Compressors ............... ..... Motor-Compressor and Branch-Circuit Overload Protection ...... ..... .......... ..... ..... ..... ..... ... Provisions for Room Air Conditioners...............

NATIONAL ELECTRICAL CODE

70- 291 707070707070-

292 293 293 295 295 296

70- 297 70- 298 70- 299 70- 299 70- 299 70- 299 70- 301 70- 301 70- 301 70- 302 70707070707070-

303 303 303 303 304 304 305

707070707070707070707070-

305 305 306 306 306 307 307 307 308 308 313 315

70- 318 70707070707070707070707070-

321 321 323 324 325 327 329 330 330 330 335 335 336

70- 337 70- 338 70- 339 70- 339 70- 340

2020 Edition

CONTENTS

445 450 Part I. Part II. Part III. 455 Part I. Part II. 460 Part I. Part II. 470 Part I. Part II. 480 490 Part I. Part II. Part III. Part IV. PartV.

Generators .......... .............................. ..... ............... T ransformers and Transformer Vaults (Including Secondary T ies) .. ......................... ..... General P rovisions ..... ..... ..... ..... ..... ..... .......... ..... .. Specific Provisions Applicable to Differe n t Types of Transformers ........... ......................... ..... T ransformer Vaults .............................. ..... ............ Phase Co nverters ......... ......................................... General . ..... ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... .... Specific Provisions Applicable to Differe n t Types of Phase Conveners ..... ..... ..... ..... ..... ..... ..... Capacitors ...... ..... ..... .......... ..... ..... ..... ..... ..... ..... ..... 1000 Volts, Nominal, and Unde r ........................ Over 1000 Volts, Nominal .................................... Resistors and Reactors .... ..... ..... ..... ..... .......... ..... .. 1000 Volts, Nominal, and Unde r ........................ Over 1000 Volts, Nominal .................................... Storage Batteries ..... .............................. ..... .......... Equipment Over I OOOVolts, Nominal ................ General . ..... ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... .... Equipment - Specific Provisions ....................... Equipment - Switchgear and Industrial Con u-ol Assemblies ...................................... ........ Mobile and Portable Equipment........................ Electrode-Type Bo ile rs .... ..... ..... ..... .......... ..... ..... ..

70- 340 70- 342 70- 342 70707070-

346 348 349 349

7070707070707070707070-

350 350 350 351 352 352 352 352 355 355 355

70- 357 70- 359 70- 360

Chapter 5 Special Occupancies 500 501 Part I. Part IL Part Ill. 502 Part I. Part IL Part Ill. 503 Part I. Part IL Part Ill. 504 505 506 510 511 51 3 514 515 516

Part I. Part IL Part III. Part IV. Part V. 517 Part I. Part IL Part III. Part IV. Part V.

2020 Edition

Hazardous (Classified) Locations, Classes I, U, and III, Divisions 1 and 2 ........ ............................. Class I Locations ................................................ ... General ..................... ............................................ Wiring ....................... ............................................ Equipment ............................................................ Class II Locations .......................................... ....... General . ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... .... Wiring ....................... ............... ............... .............. Equip ment .......................... ............... ............... .... Class III L ocations ..................... ............... ............ General . ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... .... Wiring ............................ .......... ..... .......... .............. Equip ment ......................................... ............... .... Intrinsically Safe Systems . ..... ..... ..... ..... ..... ..... ...... Zone 0, 1, and 2 Locations .................................. Zone 20, 21, and 22 Locations for Com bustible D usts o r 1gnitible Fibers/ Flyings ......................... Hazardous (Classified) Locations - Specific .... Commercial Garages, Repair and Storage ......... Aircraft Hangars .. ..... ..... ..... ..... ..... ..... ..... ..... ..... .... Motor Fuel D ispensing Facilities ......................... Bu lk Storage Plants .............................. ................ Spray Application, Dipping, Coating, and Printing P rocesses Using Flammable or Combustible Materials............................ ............. General . ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... .... Open Containers .. ................................................ Spray Application Processes... ............................. Spray Application Operations in Membrane Enclosures .... .......... ..... .......... ..... ......................... . Printing, Dipping, and Coating P rocesses ...... .... Health Care Facilities ......................... .................. General . ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... .... Wiring and P rotection ............ ..... ............... ......... Essen tial Elecu-ical System (EES) ............. ........... In ha lation Anesd1etizing Locations .................... X-Ray Installations....................... ........................

NATIONAL ELECTRICAL CODE

707070707070707070707070707070-

361 368 368 368 373 377 377 378 380 383 383 383 384 386 388

Part VI.

Part VU. 518 520

Part I. Part II. Part II I. Part IV. Part V. Part VI. Part VU. 522 Part I. Part II. Part II I. 525 Part I. Part II. Part II I. Part IV. 530 Part I. Part II. Part II I. Part IV. Part V. Part VI. 540

Part I. Part II. Part II I. Part IV. 545

707070707070-

402 408 409 411 414 420

70707070-

423 423 424 424

7070707070707070-

431 432 434 434 437 440 447 449

Part I. Part II . 547

550 Part I. Part II . Part II I. 551 Part I. Part II . Part II I. Part IV. Part V. Part VI. 552 Part I. Part II . Part II I. Part IV. Part V.

Communications, Signaling Systems, Data Systems, Fire Ala rm Systems, and Systems Less Than 120 Volts, Nominal ....................... .............. Isolated Power Systems ............................... ......... Assembly Occupancies .................... ..................... Theaters, Audience Areas of Motion Picture and Television Studios, Performance Areas, and Simila r Locations ......... ..... .......... ......................... General .... ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... ...... Fixed Stage Switchboards .................... ................ Fixed Stage Equipment Omer Than Switch boards....................... ................................. Portable Switchboards on Stage .......................... Portable Stage Equipment Otl1er Than Switch boards....................... ................................. Dressing Rooms, Dressing Areas, and Makeup Areas. ... .......... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... Equipment G rounding Conductor ..................... Control Systems for Permanent Amusement Attractions............. ............................................... General .... .............................. ..... ......................... . Control Circuits ................................ .................... Control Circuit Wiring Methods ......................... Carnivals, Circuses, Fairs, and Sim ilar Event.~ . . . . General Requirements ..................... .................... Power Sources .. ..... ..... .......... ..... ..... ..... ..... ..... ..... .. Wiring Metllods ......................... ..... ..................... Equipment G rounding and Bonding ................ . Motion Picture and Television Studios and Simila r Locations ......... ..... .......... ............... .......... General .... ............................................................ . Stage or Set ........ ..... ..... ..... ..... ..... ..... ..... ..... ..... ...... Dressing Rooms ................................ .................... Viewing, Cutting, and Patching Tables............ ... Cellu lose Niu-ate Film Storage Vaults ..... ............ Substations ........................................ .................... Motion Picture P rojection Rooms............ .......... General .... .............................. ..... .......... ............... . Equipment and Projectors of the Professional Type ................................................... .................... Nonprofessional Projectors.................. ............... Audio Signal Processing, Amplification, and Reproduction Equipment .......... ............... .......... Manufactured Build ings and Re locatable Su-uctures ..... ..... .......... ..... ..... ..... ..... ..... ..... ..... ... ... General .... ............................................................ . Re locatable Su-uctures ...... ......................... .......... Agricultural Bu ildings .. .................... .................... Mobile Ho mes, Manufactured Homes, and Mobile Ho me Parks .................. ............... ..... ....... General .... ..... ............... ............... ..... .................... . Mobile and Manufactured Homes ........... ........... Services and Feeders...... .............................. ........ Recreational Vehicles and Recreational Vehicle Parks ..... ..... ..... ..... ..... ..... ..... .......... ..... ..... ..... ..... ..... General .... ..... ..... ..... ..... ..... ..... ..... ..... ..... .......... ..... . Combination Elecu-ical Systems ............ ..... ......... Otl1er Power Sources .. ..... ..... ..... ..... ..... .......... ..... . Nominal 120-Voltor 120/ 240-VoltSystems ........ Factory Tests ... ..... ..... ..... .......... ..... ..... ..... ..... ..... .... Recreational Ve h icle Parks ........... ..... .......... ..... ... Park Trailers........ .......... ................................... .... General ........................ ............... ..... .................... . Low-Voltage Systems ......... ..... ......................... ..... Combination Elecu-ical Systems ................. ......... Nominal 120-Voltor 120/ 240-VoltSystems ........ Factory Tests ... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ....

70- 450 70- 451 70- 452

70- 453 70- 453 70- 454 70- 455 70- 457 70- 459 70- 460 70- 460 707070707070707070-

461 461 461 461 462 462 463 463 464

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464 464 465 467 467 467 467 467 467

70- 467 70- 468 70- 468 70707070-

468 468 469 470

70707070-

472 472 473 479

70707070707070707070707070-

480 480 481 482 483 489 489 491 491 492 493 493 500

70-5

NATIONAL E LECTRI CAL CODE

555

Part I. Part IL Part Ill. 590

Mari nas, Boatyards, Floating Bu ildings, and Commercial and Noncommercial Docking Facilities ................................. ......................... ...... General . ..... ..... ..... ..... ..... ..... ..... .......... ..... ..... ..... .... Marinas, Boatyards, and Docking Facilities ........ Floating Build ings ..... ................................... ........ Temporary Installations ................... ....................

7070707070-

500 500 502 504 504

Chapter 6 Special Equipment 600 Part I. Part II.

Electric Signs and Outline Ligh ting ......... .......... General . ..... ............... ............... ..... .......... ..... ..... .... Field -Installed Skeleton Tubing, Ou tline Lig h ting, a nd Secondary Wir ing .......... ............... 604 Manufactured Wiring Systems ......... ................... Office Furnish ings............................ ................... 605 610 Cranes and Hoists .......................... ...................... Part I. General ...... ................................... .................... .... Part II. Wiring ... ..... ................................... .................... .... Part Ill. Contact Conductors ............................................. Part IV. Disconnecting Means ........................................... Part V. Overcurrent Protection ....................................... Part VI. Control ................................................................. Part VIL Grounding and Bonding ..................................... 620 Elevators, Du mbwaiters, Escalators, Mo\~ ng Walks, Platform Lifts, and Stairway C hairlifi.s ..... Part I. General ................................................................. Part II. Conductors........................................................... Part Ill. Wiring ................................................................... Part IV. Installation of Conductors ................................... Part V. T raveling Cables .............. .................... ..... ............ Part VI. Disconnecting Means and Control ..................... Part VIL Overcurren t Protection ....................................... Part VIII. Mac hine Rooms, Control Rooms, Machinery Spaces, and Control Spaces ................................. Part IX. Grounding and Bonding ..................................... Part X. Emergency and Standby Power Systems............. 625 E lectric Vehicle Power Tra nsfer System ........... ... Part I. General................................................................. Part II. Equipment Construction ..................................... Part Ill. Installatio n .............. .............................................. Part IV. Wireless Power Transfer Equip ment.... ............... 626 E lectrified Truck Parking Spaces ... ..... ..... ..... ...... Part I. General . ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... .... Part II. E lectrified Truck Parking Space Electrical Wiring Systems..................................................... Part Ill. E lectrified Truck Parking Space Supply Equipment ................................................... ......... Part IV. T ransport Refrigerated Un its (TRUs) ........... ..... 630 E lectric Welders .. ..... ..... ..... ..... ..... ..... ..... ..... ..... .... Part I. General . ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... .... Part II. Arc Welders .. ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ...... Part Ill. Resistance Welders ....... .............................. .......... Part IV. Weld ing Cable .................................................. .... Audio Signal P rocessing, Amplification, and 640 Reproduction Eq uipment...................... ............. Part I. General . ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... ..... .... Part II. Permanent Audio System Installations ............... Part Ill. Portable and Temporary Audio System i nstallations........ ............................................. ..... 645 i nformation Tech nology Equipmen t ......... ......... 646 Modular Data Centers..... .................................... Part I. General . ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... ..... .... Part II. Equipment .................................... .......... ..... ......... Part Ill. Lig h ting ................................ ..... ............... ............ Part IV. Workspace . ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... .... 647 Sensitive Electronic Equipment........ .................. 650 Pipe Organs... ............................................. ..........

70-6

70- 508 70- 508 7070707070707070707070-

512 514 515 516 516 517 519 520 520 521 521

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521 521 523 525 527 528 528 530

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530 530 531 531 531 532 532 535 535 535

70- 536 70707070707070-

537 539 540 540 540 541 541

70- 542 70- 542 70- 544 707070707070707070-

545 546 549 549 552 552 553 553 554

660 Part I. Part II . Part Ill. Part IV. 665 Part I. Part II . 668 669 670 675

X-Ray Equ ipment ................................................. General .... ..... ..... ..... ..... ..... ..... .......... ..... ..... ..... ...... Contro l .... ..... ..... ..... ..... ..... ..... ..... .......... ..... ..... ...... Transformers and Capacitors.............................. Guarding and Grounding ....... ......................... ... Induction and Dielectric Heating Equipment ... General ......... ........................................................ Guarding, Grounding, and Labeling ..... ............. Electrolytic Cells ... ..... ..... ..... ..... ..... ..... ..... .......... ... Electroplating .... ..... ..... ..... .......... ..... ..... ..... ..... ...... Industrial Machinery............... ......................... ... Electrically Driven or Controlled Irrigation Machines ............. ................................... ............... Part I. General .... ..... ..... ..... ..... ..... ..... .......... ..... ..... ..... ..... . Part II . Center Pivot Irrigation Machines ......... ............... 680 Swimming Pools, Fountains, a nd Sim ilar Installations................ ......................... ................. Part I. General .... ..... ..... ..... ..... ..... ..... .......... ..... ..... ..... ..... . Part II . Permanently Installed Pools ........ ........................ Part Ill. Storable Pools, Storable Spas, Storable Hot Tubs, and Storable I mmersio n Pools ...... ........... Part IV. Spas, Hot Tubs, and Permanen tly Installed immersio n Pools............................... ................... Part V. Fountai ns ................. ........................................ ..... Part VI. Pools and Tubs for T h erapeutic Use .................. Part VII. Hydromassage Batlnubs ................................. ..... Part VIII. Electrically Powered Pool Lifi.~ .... ........................ Natural and Artificia lly Made Bodies of Water .. 682 Part I. General ......... ......................... .............................. . Part II . Installation ...................... ......................... ............. Grounding and Bonding ................................ ..... Part Ill. Integrated Electrical Systems .. ..... .................... ... 685 Part I. General ....................................... .......................... Part II . Orderly Sh utdown ... .................... ......................... 690 Solar Photovo ltaic (PV) Systems......................... Part I. General .... .......... ..... ..... ..... ..... ..... .......... .......... ...... Part II . Circuit Requirements........... .......... .................... . Disconnecting Means .................. ............... .......... Part 11 l. Part IV. Wiring Metl10ds and Materials ......... ............... .... Ground ing and Bo nd ing ................................ ..... Part V. Part VI. Marking...... .................... .............................. ........ Part VII. Connection to Oth er Sources ............................. Part VIII . Energy Storage Systems .. ..... ..... ..... ..... ..... .......... .. 691 Large-Scale Photovoltaic (PY) Electric Supply Stations .................... .......... .................... ............... 692 Fuel Cell Systems .... ..... ..... ..... .......... .......... ..... ..... . Part I. General .... .......... ..... ..... ..... ..... ..... .......... .......... ...... Part II . Circuit Requirements........... .............................. . Part 11 l. Disconnecting Means ................................. .......... Part IV. Wiring Metl10ds .................... .......... .................... . Part V. Ground ing ... .............................. .......... ................. Part VI. Marking...... .................... .............................. ........ Part VII. Connection to Oth er Circuits....... ...................... 694 Wind Electric Systems ............... .......... ................. Part I. General .... .......... ..... ..... ..... ..... ..... .......... .......... ...... Part II . Circuit Requirements........... .............................. . Disconnecting Means ................................. .......... Part 11 l. Part IV. Wiring Metl10ds .................... .......... .................... . Part V. Ground ing and Bo nd ing ................................ ..... Marking............................................................. ... P art VI. P art.VII. Connection to Oth er Sources .......... ................... 695 Fire P umps ............................................................

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555 555 556 556 557 557 557 558 558 560 561

70- 562 70- 562 70- 564 70- 564 70- 564 70- 567 70- 573 707070707070707070707070707070707070707070-

574 576 578 578 579 579 579 580 580 581 581 582 582 582 583 587 588 590 592 592 592

707070707070707070707070707070707070-

593 594 594 594 595 595 595 595 595 596 596 597 597 599 599 599 599 600

Chapter 7 Special Conditions 700 Part I. Part IL

Emergency Systems . ..... ..... ..... ..... ..... ..... .......... ..... 70- 605 General .... .......... ..... ..... ..... ..... ..... ..... ..... ..... ..... ...... 70- 605 Circuit Wiring ............... ..... ..... ..... ..... .................... 70- 607

NATIONAL ELECTRICAL CODE

2020 Edi tion

CONTENTS

Part Ill. Part IV. PartV. Part VI. 701 Part !. Part II. Part Ill. Part IV. 702 Part !. Part II. 705 Part !. Part II. 706 Part !. Part II. Part Ill. Part IV. PartV. Part VI. 708 Part !. Part II. Part Ill. Part IV. Part V. 710 712 Part I. Part II. Part II I. Part IV. Part V. Part VI. Part VII. 720 725 Part I. Part II. Part III. Part IV. 727 728 750 760 Part I. Part II. Part III. Part IV. 770 Part I. Part II. Part UL Part IV. PartV. Part VI.

Sources of Power .............................. ..... .......... ..... Emergency System Circuits for Ligh ting a nd Power ... ..... ..... ..... ..... ..... .......... ..... ..... ..... ..... ..... ..... Co1mol - Emergency Lig h ting C ircuits ............ Overcurrent Protection .. ..... ..... ..... ..... .......... ..... .. Legally Required Standby Systems ...................... General ...... .............................. ..... ........................ C ircui t Wiring ....................................................... Sources of Power .............................. ..... ............... Overcurrent Protection ....................................... Optional Standby Systems .................... ..... .......... General . ..... ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... .... Wiring ........ .............................. ..... .......... .............. Interconnected Elecu-ic Power Production Sources ................................................ .................. General ...... .............................. ..... ........................ Microgrid Systems ................................................ Energy Storage Systems ........................ ..... .......... General ...... .............................. ..... ........................ Disconnecting Means ........................................... Installation Require me n ts ................................... C ircui t Requi rements.......................................... Flow Banery Energy Storage Systems .................. Oth er Energy SlOrage Tech nologies ............... .... Critical Operations Power Systems (CO PS) ....... General . ..... ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... .... C ircui t Wiring and Equipment ........................... Power Sources and Connection .................... ...... Overcurrent Protection ...................... ..... ..... ..... .. System Performance and Analysis ..... ..... ..... ..... ... Stand-Alone Systems.. .............................. ..... ..... .. Direct Current Microgrids .... ..... ..... .......... ..... ..... . General . ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... .......... .... Circuit Requirements ........ .......... ..... ..... ..... ......... Disconnecting Means ..... ..... ......................... ........ Wiring Method s....... .......... .......... ..... ..... ..... ......... Marking ........ ..... ......................... .......... ..... ........... P rotection ........ ............... ..... ..... .................... ........ Systems over 1000 Volts........ .................... ........... Circuits and Equipment Operating at Less Than 50 Volts ..................... ............... ..... .............. Class 1, Class 2, and Class 3 Remote-Control, Signaling, and Power-Limited Circuits .............. . General . ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... .......... .... Class 1 Circuits ..... ............... ..... ..... .................... ... Class 2 and Class 3 Circuits ............. ............... ..... . Listing Requirements ..... ...................................... instrumentation T ray Cable: Type ITC .. ............. Fire-Resistive Cable Systems ..................... ........... Energy Management Systems .......... ..... ..... ..... ..... Fire Alarm Systems ........................................ ....... General . ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... .......... .... Non-Power-Lim ited Fire Alarm (NPLFA) Circuits ..... ........................................ ............... ..... . Power-Limited Fire Alarm (PLFA) Circuits ........ Listing Requirements ..... ...................................... Optical Fiber Cables ................................. ........... General . ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... .......... .... Cables Outside and Entering Build ings .......... ... Protection ....................... ...................................... G rounding Meth ods ................... ............... ..... ..... i nstallation Methods Within Bui ld ings ............... Listing Requirements ...........................................

70- 608 7070707070707070707070-

610 610 611 612 612 613 613 614 615 615 616

70707070707070707070707070707070707070707070707070-

616 616 620 62 1 62 1 62 1 622 623 624 624 624 624 625 627 628 629 629 630 630 630 63i 63i 63i 63i 63i

2020 Editio n

70707070707070707070-

632 632 633 635 642 644 645 645 646 646

70707070707070707070-

647 649 652 656 656 656 657 657 659 661

General Requi rements for Communications Systems .. ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... .... 70- 664

NATIONAL ELECTRICAL CODE

Part 111. Part IV. Part V. 805 Part I. Part i i. Part 111. Part IV. Part V. 810 Part I. Part i i. Part 111. Part IV. 820 Part I. Part i i. Part 111. Part IV. Part V. Part VI. 830 Part I. Part i i. Part 111. Part IV. Part V. Part Vl. 840 Part I. Part II. Part III. Part IV. Part V. Part Vl.

70- 63i

Chapter 8 Communications Systems 800

Part I. Part i i.

Part VU.

General .... ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... ...... Wires and Cables Outside and Entering Build ings .......................................... ..................... Grounding Methods............ .............................. .. Installation Methods Within Bu ildings ............... Listing Requi rements ........................................... Communications C ircuits .................................... General .... .............................. ..... .......... ................ Wires and Cables Outside and Entering Build ings ............................................................... Protection ............................................................. Installation Methods Within Bu ildings ............... Listing Requirements ....................... .................... Radio and Te levision Equipment ........................ General .... ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... ...... Receiving Equipment - Antenna Systems ........ Amateur and Citizen Band Transmitting and Receiving Stations - Antenna Systems .............. Interior Installation - Transmitting Stations .... Commun ity Antenna Television and Radio Distribution Systems ........... .............................. ... General .... ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... ..... . Coaxia l Cables Outside and Entering Bu ildings Protection .............................................. ............... Grounding Methods............................................ Installation Methods Within Bu ildings ......... ...... Listing Requi rements ....................... .................... Network-Powered Broadband Communications Systems ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... ..... ...... General .... ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... ..... . Cables Outside and Entering Bu ild ings... .......... Protection .............................................. ............... Grounding Methods............................................ Installation Methods Within Bu ildings ............... Listing Requi rements ... .............................. .......... Premises-Powered Broadband Communications Systems .................... ............... ..... .................... ...... General .... .................... ............... ..... .................... . Cables Outside and Entering Bu ildings ... .......... Protection ...... ............... ..... .................... ..... .......... Grounding Methods................. ............... ..... ....... Installation Methods Within Buildings ............... Premises Poweri ng of Communications Eq uipment over Communications Cables .... ...... Listing Requi rements ... .................... ....................

70- 664 707070707070-

665 666 668 675 675 675

70707070707070-

676 676 678 679 680 680 681

70- 683 70- 683 70707070707070-

684 684 684 684 685 685 686

70707070707070-

686 686 687 688 690 690 691

707070707070-

691 691 692 692 693 693

70- 693 70- 693

C hapter 9 Tables

2 4

5 5A

8 9

10 ll (A)

Pe rcent of Cross Section of Conduit and Tubing for Conductors and Cables .... ................. Radius of Conduit and Tubing Bends................ Dimensions and Percent Area of Conduit and Tubing (Areas of Conduit or T ubing for the Com binations of Wires Per mitted in Table 1, Chapter 9) ...... ..... .............................. ............... .... Dimensions oflnsulated Co nductors and Fixture Wires ..... ..... ..... ..... ..... ..... ..... ..... ..... ..... ...... Com pact Copper and Aluminum Bu ild ing Wire Nominal Dimensions** and Areas ...................... Conductor Properties .......................................... Alternating-Currem Resistance and Reactance for 600-Volt Cables, 3-Pha~e. 60 Hz, 75°C (167°F) - T h ree Single Conductors in Conduit ................................................................. Conductor Su-anding ........................................... Class 2 and C lass 3 Alternating-Current Power Source Limitations ...............................................

70- 695 70- 695

70- 696 70- 700 70- 704 70- 705

70- 706 70- 707 70- 707

70-7

NATIONAL ELECTRICAL CODE

12(A)

PLFA Alternating-C\irrent Power Source Limitations ................................... ............... ......... 70- 709

Informative Annex G: Supervisory Control and Data Acquisition ($CADA) ........ ......................................... .... 70- 833

lnforniative Annex A: Product Safety Standards .......... 70- 710

Informative Annex 1-1: Adminisu-ation and Enforcement ................................................................... 70- 834

Informative Annex B: Application Information for Ampacity Calculation ......... ............................................ 70- 716 Informative Annex C: Conduit, Tubing, and Cable Tray Fill Tables for Conduct0rs and Fixture Wires of the Same Size .... ..... .......... ..... ..... .......... ..... ..... ..... .......... .. 70- 729 Informative Annex D: Examples ................................... 70- 815

Informative Annex I: Recommended Tightening Torque Tables from UL Standard 486A-486B .............. 70- 840 Informative Annex J: ADA Standards for Accessible Design ......... ..... .......... ..... ..... .......... ..... ..... ..... .......... ..... ... 70- 842 Index ... ..... ..... ..... .......... ..... ..... ..... ..... ..... ..... ..... ..... ..... ...... 70- 845

Informative Annex E: Types of Consu-uction ............... 70- 829 Informative Annex F: Availability and Reliability for Critical Operations Power Systems; and Development and Imp lementation of Functional Performance Tests (FPTs) for Critical Operations Power Systems .............. 70- 831

70-8

NATIONAL ELECTRICAL CODE

2020 Edition

COMMITIEE PERSONNEL

NATIONAL ELECTRICAL CODE COMMITIEE These lists represent the membership at the time the Committee was balloted on the final text of this edition. Since that time, changes in the membership may have occurred. A key to classifications is found at the back of this document. Correlating Committee on National Electrical Code® MichaelJ. Johnston, Chair National Elecu-ical Contractors Association, MD [IM] Mark W. Earley, Secrelary (Non.voling) National Fire Protection Association, MA Sarah D. Caldwell, Technical Cornrniuee Adrninislmlor (Non.voling) National Fire Protection Association, l\IIA JamesE.Brunssen, Telcordia Technologies (Ericsson), NJ [UT ) Rep. Alliance for Te lecommunications lndusu-y Solutions Kevin L. Dressman, U.S. Deparunent of Energy, MD [U) Palmer L. Hickman, Electrical Training Alliance, MD [ L] Rep. International Brotherhood of Elecu-ical Workers David L. Hittinger, Independent Elecu-ical Contractors of Greater Cincinnati, O H [IM) Rep. Independent Elecu-ical Contractors, Inc.

Richard A. Holub, The DuPont Company, Inc., DE [U) Rep. American Chemistry Council John R. Kovacik, UL LLC, IL [RT) Alan Manche, Schneider Elecu-ic, KY [M) Roger D. McDaniel, Georgia Power Company, GA [UT) Rep. Elecu-ic Light & Power Group/ EEl David .A. Williams, De lta Charter Township, Ml [E) Rep. International Association of Elecu-ical Inspectors Alternates

Lawrence S. Ayer, Biz Com Electric, Inc., O H [IM ) (Alt. to David L. Hittinger) Roland E. Deike, Jr. , CenterPoint Energy, Inc., TX [UT] (Alt. to Roger D. McDaniel) James T. Dollard,Jr. , lBEW Local Union 98, PA [ L) (Alt. to Palmer L. H ickman) ErnestJ. Gallo, Telcordia Technologies (Ericsson), NJ [UT ) (Alt. to J ames E . Brunssen)

Robert A. McCullough, T uckerton, NJ [E) (Alt. to David A. Williams) Robert D. Osborne, UL LLC, NC [ RT) (Alt. to John R. Kovacik) Christine T. Porter, lntertek Testing Services, WA [RT) (Voting Alt.) George A. Straniero, AF'C Cable Systems, Inc., N.J [M) (Voting Alt.) Nonvoting

Timothy J. Pope, Canadian Standards Association, Canada [SE) Rep. CSA/Canadian Elecu-ical Code Committee William R. Drake, Fairfield, CA [M) (Member Emeritus)

D. Harold Ware, Libra Electric Company, O K [IM) (Member Emeritus)

Mark W. Earley, NF'PA Staff Liaison

2020 Edition

NATIONAL ELECTRICAL CODE

70-9

NATIONAL E LECTRI CAL CODE

Code-Making Panel No. 1 Articles 90, 100, 110, Chapter 9, Table 10, Annex A, Annex H , Annex I, and AnnexJ Kenneth P. Boyce, Chair UL LLC, IL [RT] Louis A. Barrios, Sh e ll Global Solutions, TX [U] Rep. American C hemistry Council Roland E. Deike, Jr. , CenterPo in t Energy, Inc., TX [UT] Rep. Electric Ligh t & Power Group/ EEi ErnestJ. Gallo, Telcordia Technologies (Ericsson), NJ [U] Rep. Alliance for Telecommunications lnduso-y Solutions Palmer L. Hickman, Elecu-ica l Training Alliance, MD [ L] Rep. ln ternational Brotherhood of Elecu-ical Workers

Donald R. lverson, National Eleco-ical Manufacturers Association, Ml [M] Rep. National Electrical Manufacture rs Association James F. Pierce, Intertek Testing Senkes, O R [RT] Harry J. Sassaman, Forest Elecu-ic Corporation, NJ [IM] Rep. National Electrical Conn-actors Association Kent A. Sayler, P2S Inc., CA [ U] Rep. Institute ofElecu-ical & Electronics Engineers, Inc.

David L. Hittinger, Independent Electrical Contractors of Greater Cincinnati, OH [IM] Rep. Independent Electrical Contractors, Inc.

Mohinder P. Sood, City of Alexandria, VA [E] Rep. International Association of Elecu-ical Inspectors Alternates

James E. Brunssen , Telcordia Technologies (Ericsson ), NJ [U] (Al L to ErnestJ. Gallo) Mark Christian, Elecu·ical Training Alliance, TN [L ] (AIL to Palmer L. Hickman) Jon Coulimore,J C Electric, Inc., WA [IM] (AIL to David L. Hittinger) Timothy Garland, Keene State College, NH [U] (Voting AIL) Larry Geyer, Quality Electric Inc., ID [IM] (AIL to H arryJ. Sassaman) Joseph Marquardt, ExxonMobil Production Company, TX [U] (AIL to Louis A. Barrios) Roger D. McDaniel, Georgia Power Company, GA [UT] (AIL to Ro land E. De ike, J r.)

Kenneth L. McKinney, Jr., UL LLC, NC [RT] (Alt. to Ke nneth P. Boyce) Donald R. Offerdahl, lntertek Testing Services, N D [RT] (Alt. to James F. Pierce) Michael C. Stone, National Electrical Manufacture rs Association, CA[M] (Alt. to Donald R. Iverson) Frank E. Tyler, The Du Po n t Company, Inc., DE [ U] (AIL to Kent A. Sayler) Charles Valaer, City Of Gle ndale Californ ia, CA [ E] (AIL to Mohinder P. Sood)

Nonvoting Ark Tsisserev, AES Engineering, Canada [SE] Rep. CSA/Canadian Eleco-ical Cod e Committee

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NATIONAL ELECTRICAL CODE

2020 Edi tion

COMMITIEE PERSONNEL

Code-Making Panel No. 2

Articles 210, 220, Annex D, Examples DI through D6 Mark R. Hilbert, Chair MR Hilbert Electrical Inspections & Training, NH [ E] Rep. In ternational Association of Electrical Inspectors Mathher Abbassi, New York City Department Of Buildings, NY [E] Charles L. Boynton, The DuPont Company, Inc., TX [U ] Rep. American Chemistry Council Daniel Buuck, National Association of Home Builders (NAHB), DC [U] Rep. National Association of Home Builders Steve Campolo, Leviton Manufacturing Company, Inc., NY [M] Thomas A. Domitrovich, Ea.ton Corporation, MO [M] Rep. National Electrical Manufacturers Association Nehad El-Sherif, Saskatoon, SKCanada [U ] Rep. lnstimte of Electrical & Electronics Engineers, Inc.

Thomas L. Harman, University of Houston-Clear Lake, TX [SE] DavidW.Johnson, CenTex !EC, TX [ IM] Rep. Independent Electrical Contractors, Inc . Alan Manche, Schneider Electric, KY [M] John McCamish, NECA lBEW Electrical Training Center, OR [L] Rep. International Brotherhood of Electrical Workers Christopher J. Pavese, D uke Energy, KY [UT ] Rep. Electric Light & Power Group/ EEi Frederick P. Reyes, UL LLC, NY [ RT] Michael Weaver, M&W Electric, OR [ IM] Rep. National Electrical Contractors Association

Alternates William B. Crist, Jr., lES Residential lnc., TX [ IM] (AIL to David W. Johnson) Andrew Kriegman, Leviton Manufacturing Company, Inc., NY [M] (AIL to Steve Campolo) Brett Larson, Schneider Electric, IA [M] (AIL to Alan Manche) Cesar Lujan, National Association of H ome Builders ( NAHB), D C [U] (AIL to D aniel Buuck) Roger D. McDaniel, Georgia Power Company, GA [UT] (AIL to ChristopherJ. Pavese) Danie!J. Naughton,JATC of Greater Boston, MA [L ] (Alt. to J ohn McCam ish)

Fred N eubauer, Neubauer Electric I nc., CA [ IM] (AIL to Michael Weaver) Robert D. Osborne, UL LLC, NC [ RT] (Alt. to Frederick P. Reyes) Fernando E. Pacheco, Methanex Chi le SA, TX [U] (AIL to Charles L. Boynton) Brian E. Rock, H ubbell Incorporated, CT [M] (Alt. to Thomas A. Domitrovich) JosephJ. Wages, Jr., International Association of Electrical Inspectors, T X [E] (Alt. to Mark R. Hilbert)

Nonvoting Douglas A. Lee, U.S. Consumer Product Safety Commission, MD

Andrew M. Trotta, U.S. Consumer Product Safety Commission, MD

[CJ

[CJ Rep. U.S. Consumer Product Safety Commission

2020 Edition

NATIONAL ELECTRICAL CODE

Rep. U.S. Consumer Product Safety Commission

70-11

NATIONAL E LECTRICAL CODE

Code-Making Panel No. 3 Articles 300, 590, 720, 725, 727, 728, 760, and Chapter 9, Tables 11 (A) and (B) , and Tables l 2(A) and (B) Robert A.Jones, Chair Independent Electrical Contractors, Inc., T X [IM] Rep. Independent EleCLrical Contractors, lnc. Richard S. Anderson, RTKL Ament - Safety - Part 1: General RequiremenlS or U L 62368-1-20 14, Audio/Video lnfonnation and Comnmnication Technology Equipment Part 1: Safety Requiremeuts.

Information Technology Equipment Room. A room within the information technology equipment area that contains the information technology equipment. f75:3 .3.l 4] (CMP-12) lnnerduct. A nonmetallic raceway placed within a large r raceway. (CMP-16) Interactive Inverter. An inverter intended for use in paralle l with power source(s) such as an electric utility to supply common loads and capable of delivering power to the utility. (CMP-13) Interactive System. An electric power production system that is operating in parallel with and capable of delivering ene rgy to an electric primary source supply system. (CMP-4)

Hybrid System. A system comprised of multiple power sources. These power sources could include photovoltaic, wind, microhydro generators, engine-driven generators, and others, but do not include electric power production and distribution network systems. Energy storage systems su ch as batteries, flywheels, or superconducting magnetic storage equipment do not constitute a power source for the purpose of this definition . The energy regenerated by an ove1-hauling (descending) elevator does not constiune a power source for the purpose of this definition. (CMP-4)

Interrupting Rating. The h ighest current at rated voltage that a device is identified to interrupt under standard test conditions. (CMP-10)

Identified (as applied to equipme nt). Recognizable as suitable for the specific purpose, function, use, environment, application, and so forth, where described in a particular Code requirement. (CMP-1)

Intersystem Bonding Termination. A device that provides a means for connecting intersystem bonding conductors for communications syste ms to the grounding e lectrode syste m. (CMP-16)

Informational Note: Some examples of ways to determine suitability of equipment for a specific purpose, environment, or application include investigations by a qualified testing laboratory (listing and labeling), an inspection agency, or other organizations concerned with product evaluation.

In Sight From (Within Sight From, Within Sight). \tion to (1) through (5), (8), and ( 10): Listed locking support and mounting receptacles utilized in combination with cmnpatible attachment fitting.5 installed for the purpose of serving a ceiling luminaire or ceiling fan shall not be required to be ground-fault circuit-interrupter protected. If a general1Jinpose convenience receptacle is integral to the ceiling luminaire or ceiling fan, CFC! protection shall be provided. ( 11 )

(12)

La undry areas Bathtubs and shower stalls - where receptacles are installed within 1.8 m (6 ft) of the ou tside edge of the bathnib or shower stall

(C) Crawl Space Lighting Outlets. GFCI protection shall be provided for lig hting outlets not exceeding 120 volts installed in crawl spaces.

(D) Specific Appliances. Unless GFCI protection is provided in accordance wid1 422.5(B)(3) through (B)(5), the outlets supplying the appliances specified in 422.5(A) shall have GFCI protection in accordance with 422.5(B)(l) or (B)(2) . Where the appliance is a vending machine as sp ecified in 422.5(A) (5) and GFCI protection is n ot provided in accordance wim 422.5(B)(3) or (B)(4), b ranch circuits supplying vending machines shall have GFCI protection in accordance with 422.5( B) (l ) or (B)(2) . (E) Equipment Requiring Servicing. GFCI protection shall be provided for the receptacles required by 210.63.

Exception No. 2: In industrial occupancies, whei·e conditions of maintenance and supervision ensure that only qualified persons service the installation, autotransformers shall be permitted to supply nominal 600-volt loads from nominal 480-volt systems, and 480-volt loads from nominal 600-volt systems, without the connection to a similar grmmded conductm:

210.10 Ungrounded Conductors Tapped from Grounded Systems. Two-wire de c ircuits and ac c ircuits of two o r more ungrow1ded conducto rs shall be permitted to be tapped fro m the ungrounded conductors of c ircui ts that have a grow1ded neutral conductor. Switching devices in each tapped circuit shall have a pole in each ungrounded conductor. All poles of multipole switching devices shall ma nually switch toged1er whe re such switc hing devices also serve as a disconnecting means as requit-ed by the following: (1)

(2) (3) (4) (5) (6) (7)

410.93 for double-pole switched la mpholders 410.104(B) for electric-discharge lamp auxi liary equip· me nt switching d evices 422.3 1 (B) for an ap pliance 424.20 for a fixed e lectric space-heating unit 426.5 1 fo r e lectric deicing and snow-melting equipment 430.85 for a motor controller 430.1 03 for a motor

210.11 Branch Circuits Required. Branch circ uits for lig hting and for appliances, including motor-operated applian ces, sha ll be provided to supply the loads calculated in accordan ce with 220 .1 0. In addition, b ranch circuits shall b e provided for specific loads not covered by 220.10 where required elsewhere in this Code and fo r dwelling unit loads as specified m 210.ll (C) . (A) Number of Branch Circuits. The minimum number of branch circuits shall be determined from the total calculated load a nd the size or rating of the c ircui ts used. In a ll installations, the number of circuits shall be sufficient to supply the load served. In no case sha ll the load on any c ircui t exceed the maximum specified by 220.18 . (B) Load Evenly Proportioned Among Branch Circuits. Where the load is calculated on m e basis of vol t-ampe1-es per square meter o r per square foot, the wiring syste m up to and including the branch-circuit panelboard(s) shall be provided to serve not less than d1e calculated load. This load shall be evenly proportioned a mong multioudet branch circuits within the panelboard (s) . Branch-circuit overcurrent devices a nd circuits sha ll be required to b e installed o nly to serve the connected load.

(F) Outdoor Outlets. All outdoor outlets for dwellings, other than those covered in 210.8(A)(3), Exception to (3), that are

2020 Edition

NATIONAL ELECTRICAL CODE

70-63

210.11

ARTICLE 210-BRANCH CIRCUITS

(C) Dwelling Units. (1) Small-Appliance number of branch section, nvo or more shall be provided 210.52( B) .

Branch Circuits. In addition to the circuits required by other parts of this 20-ampere small-appliance branch circuits fo1- all receptacle outlets specified by

(2) Laundry Branch Circuits. In addition to the number of branch circuits required by other pa1-ts of this section, at least one additional 20-ampere branch circuit shall be provided to supply the laundry receptacle outlet(s) required by 210.52 (F). This circuit shall have no other outlets.

( 4)

(3) Bathroom Branch Circuits. In addition to the number of branch circuits required by other parts of this section, one or more 120-volt, 20-ampere branch circuit shall be provided to supply bathroom(s) receptacle outlet(s) required b y 210.52(D) and any countertop and similar work surface receptacle outlets. Such circuit5 shall have no otl1er outlets. 1!,xception: Where the 20-arnpere circuit supplies a singf,e bathroorn, outlets for other equiprnent within the sarne bathroorn shall be perrnitted to be supplied in accordance with 210.23(A)(1) and (A)(2). (4) Garage Branch Circuits. In addition to the number of branch circuits required by other parts of this section, at least one 120-volt, 20-ampere branch circuit shall be installed to supply receptacle outlets required by 210.52(G) (1) for attached garages and in detached garages witl1 electric power. This circuit shall have no other outlets.

(5)

Exception: This circuit shall be permitted to supply readily accessible outdoor receptacle outlets. 210.12 Arc-Fault Circuit-Interrupter Protection. Arc-fault circuit-interrupter protection shall be provided as required in 210.1 2(A), (B), (C), and (D) . The arc-fault circuit interrupter shall be installed in a readily accessible location. (A) Dwelling Units. All 120-volt, single-phase, 15- and 20ampere branch circuits supplying outlets or devices installed in dwelling unit kitchens, family rooms, dining rooms, living rooms, parlors, libraries, dens, bedrooms, sun rooms, recreation rooms, closets, hallways, laundry areas, or similar rooms or areas shall be protected by any of the means described in 210.1 2(A)( l ) through (6): ( 1)

(2)

(3)

A listed combination-type arc-fault circuit inte1Tupter installed to provide protection of the entire branch circuit A listed branch/feeder-type AFCI installed at the origin of the branch-circuit in combination with a listed outlet branch-circuit-type arc-fault circuit interrupter installed at the first outlet box on the branch c ircuit. The first outlet box in tl1e branch circu it shall be marked to indicate that it is the first outlet of the circuit. A listed supplemental arc protection c ircuit breaker installed at the origin of the branch circuit in combination with a listed outlet branch-circuit-type arc-fault ci1-cuit interrupter installed at the first outlet box on the branch circuit where all of tl1e following conditions are met: a. The branch-circuit wiring shall be continuous from the branch-circuit overcurrent device to the outlet branch-circuit arc-fault circuit interrupter.

70-64

(6)

b. The maximum length of the branch-circuit wmng from the branch-circuit overcurrent device to the first outlet shall not exceed 15.2 m (50 ft) for a 14 AWG conductor or 21.3 m (70 h) for a 12 AWG conductor. c. The first outlet box in the branch circuit shall be marked to indicate that it is the first outlet of the circuit. A listed outlet branch-circuit-type arc"fault circuit inte1-rupter installed at the first outlet on the branch circuit in combination with a listed branch-circuit overcurrent protective device where all of the following conditions are met: a . The branch-ci1-cuit wiring shall be continuous from the branch-circuit overcurrent device to the outlet branch-circuit arc-fault circuit interrupter. b. The maximum length of the branch-circuit wiring from the branch-circuit overcurrent device to the first outlet s hall not exceed 15.2 m (50 ft) for a 14 AWG conductor or 21 .3 m (70 ft) for a 12 AWG conductor. c. The first outlet box in the branch circuit shall be marked to indicate that it is tl1e first outlet of tl1e circuit. d . The combination of the bran ch-circuit overcurrent device and outlet branch-circuit AFCI shall be identified as meeting the requirements for a syste m combination-type AFCI and s hall be listed as such. If metal raceway, metal wireways, metal auxiliary gutters, or Type MC, or Type AC cable meeting tl1e applicable requirements of250 .118, with metal boxes, metal conduit bodies, and metal enclosures are installed for the portion of the branch circuit between the branch-circuit overcurrent device and the first outlet, it shall be permitted to install a listed outlet branch-circuit-type AFCJ at the first outlet to provide protection for the re maining portion of tl1e branch circuit. Where a listed metal or nonmetallic conduit or tubing or Type MC cabl e is e ncased in not less than 50 mm (2 in. ) of concrete for the portion of the branch circuit between the branch-circuit overcurrent device and the first outlet, it shall be pennitted to install a listed outlet branchcircuit-type AFCI at the first outlet to provide protection for the remaining portion of the branch circuit.

Exception: AFC/ protection shall not be required for an individual branch circuit supplying a fire alarm systern installed in accordance with 760.41 (B) or 760.121 (B). The branch circuit shall be installed in a metal raceway, rnetal auxilim)' gutter, steel-armored cable, 'Pype MC or Type AC, rneeting the applicable requirements of 250.118, with metal boxes, conduit bodies, and enclosures. lnfo1-mational Note No. I: For information on combination-type and branch/ feeder-type arc-fault circuit interrupters, see UL 1699-2011, Standard/or Arc-Faull Circuit lnwrru/Jlers. For information on outlet branch-tion No. 1: If exempted by special permission, the metal frame of elect1ically heated appliances that have the frame permanently and effectively insulated from ground shall not be required to be grounded. l!.xception No. 2: Distribution af:rparatus, such as transformer and capacitor cases, mounted on wooden poles at a height exceeding 2.5 m (8 ft) above ground or grade level shall not be required to be grounded.

2020 Edition

NATIONAL ELECTRICAL CODE

250.114

Exception No. 3: Listed equipment protected by a system of double insu1.ation, or its equivalent, shall not be required to be connected to the equipment grounding conduct01: v\!7iere such a system is employed, the equipment shall be distinctively marked.

250.112 Specific Equipment Fastened in Place (Fixed) or Connected by Permanent Wiring Methods. Except as permitted in 250.112(F) and (I ), exposed, normally non-currentcarrying m etal parts of equipme n t described in 250.11 2(A) through (K), and normally non-cw-rent-can y ing metal parts of equipment and e nclosures described in 250.11 2(L) and (M), shall be conn ected to an equipme nt grounding condu ctor, regardless of voltage. (A) Switchgear and Switchboard Frames and Structures. Switchgear 01- switchboard frames and stru ctures supporting switching equipment, except frames of 2-wire de switch gear or switchb oards where effectively insulated from ground. (B) Pipe Organs. Generator and motor frames in an electrically operated pipe organ, unless effectively insulated from ground a nd the motor driving it. (C) Motor Frames. Motor frames, as provided by 430.242. (D) Fnclosures for Motor Controllers. Enclosures for motor conn-oilers unl ess attached to ungrounded portable equipment.

(E) Elevators and Cranes. Elec trical equipme n t for e levators and cranes. (F) Garages, Theaters, and Motion Picture Studios. Electrical equipment in commerc ia l garages, th eaters, and motio n picture studios, except penda nt la mpholders supplied by circuits not over 150 volts to g round.

(G) Electric Signs. Elec tric signs, outline lig hting, a nd associated equipment as provided in 600.7. (H) Motion Picture Projection Equipment. Motion picture projection equipment. (I) Remote-Control, Signaling, and Fire Alarm Circuits. Equipmen t supplied by Class l circuits shall be grounded unless operating at less than 50 volts. Equipme n t supplied by Class 1 power-limited circ uits, by Class 2 and Class 3 remote-control and signaling circuits, and by fire a larm c ircui ts shall be grom1ded where system grounding is required by Part II o r Part VIII of th is article.

(J) Luminaires . Luminaires a5 provided in Part V of Article 4 10. (K) Skid-Mounted Equipment. Permanently mounted electri-

cal equipment and skids shall be connected to the equip me nt grounding conductor. Wire-type equipment grounding conductors shall be sized as required by 250.122. (L) Motor-Operated

Water Pumps. Motor-operated pumps, including the submersible type.

water

(M) Metal Well Casings. '!\There a submersible pump is used in a metal well casing, the well casing shall be con nected to the pump circuit equipment grou nding conductor.

250.114 Equipment Connected by Cord and Plug. Exposed, normally non-current-carrying metal parts of cord-and-plugcon nected eq uipme n t shall be conn ected to th e equipment grounding conductor under any of th e fo llowi ng conditions:

70- 129

250.116

ARTICLE 250- GROUNDING AND BONDING

.Exception: Listed tools, listed appliances, and listed equipment covered in 250.114(2) through (4) shall not be required to be connected to an equipment grmmding conductor where protected by a system of double insulation or its equivalent. Double insulated equipment shall be distinctively marked.

(1) (2)

In hazardous (classified) locations (see Articles 500 through 517) '!\'here operated at over 150 volts to g round

J!.'xception No. 1 to (2): Motors, where guarded, shall not be required to be connected to an equipment grounding conduct01: Exception No. 2 to (2): Metal frames of electrically heated appliances, exempted by special permission, shall not be required to be connected to an equipment grounding conductm; in which case the frames shall be permanently and effectively insulated from ground.

(3)

In residential occupancies:

(4 )

a . Refrigerators, freezers, and air conditioners b. Clothes-washing, clothes-drying, and dish-washing machines; ranges; kitchen waste disposers; information tech nology equipment; sump pumps; and e lectrical aquarium equipment c. H and-held motor-operated tools, stationa ry and fixed motor-operated tools, and lig ht industrial motoroperated tools d . Motor-operated appliances of the following types: hedge clippers, lawn mowers, snow bl owers, and wet scrubbers e . Portable handlamps and portable luminaires In od1er than residential occupancies: a. Refrigerators, freezers, and air c onditioners b. Clothes-washing, clothes-drying, and dish-washing mac hines; information technology equipment; sump pumps; and e lecu-ical aqua1-ium eq uipment c. H and-h e ld motor-operated tools, stationary and fixed motor-operated tools, and lig ht industrial motoroperated tools cl. Motor-operated appliances of dle following types: hedge clippers, lawn m owers, snow bl owers, and wet scrubbers e . Portable ha ncllamps a nd portable luminaires f. Cord-and-plug-connected appliances used in damp or wet locations or by persons standing on the ground, standing on metal floors, or working inside of metal tanks or boilers g. Tool5 likely to be used in wet or conductive locations Exception: Tools and portable handlamps and portable luminaires likely to be used in wet or conductive locations shall not be required to be connected to an equipment grounding conduct01· where supplied thrmigh an isolating transformer with an ungrounded secondary of not over 50 volts.

250.116 Nonelectrical Equipment. The metal parts of the following nonelectrical equipment described in this section shall be connected to dle equipment grounding conductor: ( 1)

(2)

Frames and tracks of elecu·ically operated cranes and hoists Frames of nonelecu·ically d1-iven elevator cars to which electrical conductors are attached

70-130

(3)

H and-operated metal shifting ropes or cables of ele ctric e levators Informational Note: Wh ere extensive metal in or on bu ild ings or structures may become energized and is su~ject to personal contact, adequate bonding a nd g rounding will p rovide additional safety.

250.118 Types of Equipment Grounding Conductors. The equipment g rounding conductor run with or enclosing the circuit condu ctors shall be o n e or more or a combination of die following: (1)

(2) (3) (4) (5)

(6)

A copper, aluminum, or coppe r-clad alum inum conductor. This conductor shall be solid or stranded; insulated, covered, or bare; and in the form ofa wi re or a busbar of any shape. Rigid metal conduit. Intermediate metal conduit. Electrical metallic tubing. Listed flexible metal conduit meeting all the following conditions: a . The conduit is terminated in listed fitti ngs. b. The circuit conductors contained in die conduit are protected by overcurrent devices rated at 20 amperes or less. c. The size of the conduit does not exceed metric d esignator 35 (trad e size 1Y.,). cl. The combined le n gth of flex ible metal conduit, flexible metallic n1bing, a nd liquidtig h t fl exible metal conduit in the same effective ground-fault current path does not exceed 1.8 m (6 ft) . e . If used to connect equi pment where flexibil ity is necessa1-y to minimize t he transmission of vibration from equipment or to provide flexibility for e quipment dlat requires movement after installation, a wire-type equipment grounding conductor shall be installed. Listed liquicltight flex ible metal conduit meeting all the following conditions: a . The conduit is terminated in listed fittings. b. For metric designators 12 through 16 (trade sizes % through \-2), the circuit conductors contained in the condui t are protected by overcurrent devices rated at 20 ampe 1·es or less. c. For metric design ators 21 through 35 (trade sizes 'Y. through 1 Y.,), dl e circuit conductors contained in the conduit are protected b y overcurrent devices rated not m ore than 60 a mperes and there is no flexible metal conduit, flex ible m etallic n ibing, or liquidtigh t flexible m etal conduit in meu·ic designators 12 through 16 (trade sizes %through \12) in the effective ground-fault current pa th. d . The combined le n gth of flexible metal conduit, flexible metalli c nibing, a nd liquicltight flexible me tal conduit in the same effective ground-fault current path does not exceed 1.8 m ( 6 ft) . e . If used to connect e quipment where flexibility is necessa1-y to minimize the transmission of vibration from equipme n t or to provide flexibili ty for equipment dlat requires movem ent after instal la tio n, a wire-type equipment grounding conductor shall be installed.

NATIONAL ELECTRICAL CODE

2020 Edi tion

ARTICLE 250- GROUNDING AND BONDING (7)

(8) (9) (10)

(11) (12) (13) (14)

250.120

Flexible metallic tubing where the tubing is terminated in listed fittings and meeting the following conditions:

have insulation or cove1ing that is green with one or more yellow stripes.

a . The circuit conductors contained in the tubing are protected b y overcurrent devices rated at 20 amperes or less. b. The combined length of flexible metal conduit, flexible metallic tubing, and liquidtight flexible metal conduit in the same effective ground-fault current path does not exceed 1.8 m (6 ft) . Armor of Type AC cable as provided in 320.108. The copper sheath of mineral-insulated, metal-sheathed cable Type MI. Type MC cable that provides an effective ground-fault current path in accordance with one or more of the following:

(A) Conductors 4 AWG and Larger. Equipment groundi ng conductors 4 AV\TG and larger shall comply with 250 .11 9(A) (1) and (A) (2) .

a . It contains an insulated or uninsulated equipment grounding conductor 111 compliance with 250.118(1) . b. The com bined metallic sheath and uninsulated equipment grounding/ bonding conductor of interlocked metal tape-type MC cable that is listed and identified as an equipment grounding conductor c. The metallic sheath or the combined metallic sheath and equipment grounding conductors of the smooth or corrugated rube-type MC cable that is listed and identified as an equipment grounding conductor Cable trays as permitted in 392.10 and 392.60. Cablebus framework as permitted in 370.60(1) . Other listed electrically continuous metal raceways and listed auxiliary gutters. Surface metal raceways listed for grounding.

(1)

Exception: Conductors 4 A WC and larger shall not be required to be marked in conduit bodies that contain no splices or unused hubs.

(2)

Exception No. 1: Power-limited Class 2 or Class 3 cables, power-limited fire alarm cables, or communications cables containing only circuits operating at less than 50 volts ac or 60 volts de where connected to equipment not required to be gmunded shall be permitted to use a conductor with green insulation or green with one or more yellow stripes for other than equipment grounding pmposes.

(B) Multiconductor Cable. One or more insulated conductors in a multiconductor cable, at the time of installation, shall be permitted to be permanen tly identified as equipment grounding conductors at each end and at every point where the conductors are accessible by o ne of the followi ng means:

(1) (2) (3)

Exception No. 3: Conductors with green insulation shall be permitted to be used as ungrounded signal conductors where installed between the output terminations of traffic signal control and traffic signal indicating heads. Signaling circuits install.ed in accordance with this exception shall include an equipment grounding conductor in accordance with 250.118. Wire-type equipment grounding conductors shall be bare or

2020 Edition

NATIONAL ELECTRICAL CODE

Su-ipping the insulation from the enti1·e exposed length. Coloring the exposed insulation green. Marking the exposed insulation vvith green tape or g reen adhesive labels. Identification shall encircle the conductor.

(C) Flexible Cord. Equipment grounding conductors in flexi-

ble cords shall be insulated and shall have a continuous outer finish that is eitl1er g reen or green with one o r more yellow su·ipes. 250.120 Equipment Grounding Conductor Installation. An equipment grounding conductor shall be installed in accordance with 250.1 20(A), (B), and (C) . (A) Raceway, Cable 'frays, Cable Armor, Cablebus, or Cable Sheaths. V\'here i t consists of a raceway, cable tray, cable armor, cablebus framework, or cable sheath or where it is a wire within a raceway or cable, it shall be installed in accordance with the applicable provisions in this Code using fittings for j oin ts and terminations approved for use with the type raceway o r cable used. All connections, joint~, and fi ttings shall be made tight using suitable tools. Informational Note: See the UL guide information on FHIT systems for equipmen t grounding conductors installed in a raceway that are part of an e lectrical circuit protective system or a fire-rated cable listed to maintain circuit integrity.

J',xception No. 2: R exible cords having an integral insulation and jacket withmit an equipment grounding conductor shall be permitted to have a continuous outer finish that is green. Informational Note: An example of a flexible cord with integraltype insulation is Type SPT-2, 2 conductor.

Identification shall encircle the conductor and shall be accomplished by one of the fo llowi ng: a. Stripping the insulation 01· covering from the entire exposed length b. Coloring the insulation or covering green at the termination c. Marking the insulation or covering with green tape or green adhesive labels at tl1e termination

Informational Note: For a definition of effective groundfattll curnml j1alh, see Article 100.

250.119 Identification of Equipment Grounding Conductors. Unless required elsewhere in this Code, equipment grounding conductors shall be permitted to be bare, covered, or insulated. Individually covered or insulated equipment grounding conducto1·s shall have a continuous outer finish that is e ither green or green with one or more yellow su·ipes except as permitted in this section. Conductors with insulation or individual covering that is green, green with one or more yellow su-ipes, or otherwise identified as permitted by this section shall not be used for ungrounded or grounded circuit conductors.

An insulated or covered conductor 4 AWG and larger shall be permitted, at the time of i nstallation, to be permanently identified as an equipment groundi ng conductor at each end and at every point where the conductor is accessible .

(B) Aluminum and Copper-Clad Aluminum Conductors. Equipment grounding conductors of bare, covered, or insulated aluminum or copper-clad aluminum shall comply with tl1e following: (l)

Unless part of a suitable Chapter 3 cable wiring method, bare or covered conductors shall not be installed where subject to corrosive conditions or be installed in direct contact with concrete, masonry, or the earth.

70- 131

250.120 (2)

(3)

ARTICLE 250- GROUNDING AND BONDING

Terminations made within outdoor enclosures that are listed and identified for the enviromnent shall be pennitted within 450 mm (18 in.) of the bottom of the enclosure. Aluminum or copper-dad aluminum conductors external to buildings or enclosures s hall not be terminated within 450 mm (18 in.) of the earth, unless terminated within a listed wire connector system.

(D) Motor Circuits. Equipment groundi ng conductors for motor circuits shall be sized in accordance with 250.122(D) (1) or (D) (2) .

(1) General. The equipment grounding conductor size shall not be smaller than determined by 250.122(A) based on the rating of the branch-circuit s hort-circuit and ground-fault protective device .

(C) Equipment Grounding Conductors Smaller Than 6 AWG. Where not routed with circuit conductors as permitted in 250.1 30(C) and 250.134(A) Exception No. 2, equipment grounding conductors smaller than 6 AWG shall be protected from physical damage by an identified raceway or cable armor unless installed with.in hollow spaces of the framing members of buildings or structures and where not subject to physical damage.

(2) Instantaneous-Trip Circuit Breaker and Motor Short-Circuit Protector. If the overcurrent device is an instantaneous-trip circuit breaker or a motor short-circuit protector, the equipment grounding condu ctor shall be sized not smaller than that given by 250.1 22(A) using the maximum permitted rating of a dual element time-delay fuse selected for branch-circuit shortcircuit and ground-fault protection in acco1·dance with 430.52(C) (1), Exception No. l.

250.121 Restricted Use of Equipment Grounding Conductors.

(E) Flexible Cord and Fixture Wire. The equipment grounding conductor in a flexible cord with the largest circuit conductor 10 AWG or smaller, and the equipment grounding conductor used with fixnire wires of any size in accordance with 240.5, shall not be smaller than 18 AWG copper and shall not be smaller than the circuit conductors. Th e equipment grounding conductor in a flexible cord with a circuit conductor larger than 10 AV•/G sh all be sized in accmdance with Table 250.122 .

(A) Grounding Electrode Conductor. An equipment grounding conductor shall not be used as a grounding electrode conductor. Exception: A wire-t1pe equipment grounding conductor installed in compliance with 250.6(A) and the applicable requirements for both the equipment grounding conductor and the grounding electrode conductor in Pa1ts II, III, and VI of this article shall be permitted to serve as both an equipment grounding conductor and a grounding electrode conductor. (B) Metal Frame of Building or Structure. The structural metal frame of a building or strucnire shall not be used as an equipment grow1ding conductor. 250.122 Size of Equipment Grounding Conductors. (A) General. Copper, aluminum, or copper-clad aluminum equipment grounding conductors of the wire type shall not be smaller than shown in Table 250.122. The equipment grounding conductor shall not be required to be larger than the circuit conductors supplying the equipment. If a cabl e tray, a raceway, or a cable armor or sheath is used as the equipment grounding conductor, as provided in 250.11 8 and 250.1 34(1), it shall comply with 250.4(A) (5) 01· (B) (4) . Equipment grounding conductors shall be permitted to be sectioned within a multiconductor cable, provided the combined circular mil area complies with Table 250.1 22.

(B) Increased in Size. If ungrounded conductors are increased in size for any reason other than as required in 310.1 5(B) or 310.1 5(C), wire-type equipment grounding conductors, if installed, shall be increased in size proportionately to the increase in circular mil area of the ungrounded conductors. 1!,xception: Equipment grounding conductors shall be permitted to be sized by a qualified person to provide an effective ground fault current path in accordance with 250.4(A)(5) or (B)(4). (C) Multiple Circuits. A single equipment grounding conductor shall be permitted to be installed for multiple circuits that are installed in the same raceway, cable, u·ench, or cable tray. It shal 1 be sized from Table 250.1 22 for the largest overcurrent device protecting circuit conductors in the raceway, cable, trench, or cable tray. Equipment grounding conductors installed in cable trays shall meet the minimum requirements of 392. l O(B) (l) (c) .

70-132

(F) Conductors in Parallel. For circuits of pa rallel conductors permitted in 310.l O(G), the equipment grounding conductor shall be installed in accordance with 250.1 22(F) (l) or (F)(2) . a5

(1) Conductor Installations in Raceways, Auxiliary Gutters, or Cable Trays. (a) Single Raceway or Cable Tray, Auxilimy Gutter, or Cable Tray. If circuit conducto1·s a1·e connected in parallel in the same raceway, auxiliary gutter, or cable tray, a single wire-type conductor shall be permitted as the equipment grounding conductor. The wi1·e-type equipment grounding conductor shall be sized in accordance with 250.122, based on the overcurrent protective device for the feeder or branch circuit. (b) Muliiple Raceways. If conductors are installed i n multiple raceways and are connected in parallel, a wire-type equipment grounding conductor, if used, shall be installed in each raceway and shall be connected in parallel. The equipment grounding conductor installed in each raceway shall be sized in accordance with 250.122 based on the rating of th e overcurrent protective device fm the feede1· or b1-anch circuit. (c) Wire-Type Equipment Grounding Conductors in Cable 11·ays. Wire-type equipment grounding conductors installed in cable trays shall meet the minimwn requirements of 392.lO (B) (1) (c) . (d) Metal Raceways, A uxiliary Gutters, or Cable 11·ays. Metal raceways or auxiliary gutters in accordance with 250 .11 8 or cable trays complying with 392.60(B) shall be permitted as the equipment grounding conductor. (2) Multiconductor Cables. (a) Except as provided in 250.1 22(F)(2)(c) for raceway or cable tray installations, the equipment grounding conductor in each multiconductor cable shall be sized in accordance with 250.1 22 based on the overcurrent protective device for the feeder or branch circuit. (b) If c ircuit conductors of multiconductor cables are connected in parallel, the equipment groundin g conductor (s) in each cable shall be connected in parallel.

NATIONAL ELECTRICAL CODE

2020 Edition

ARTICLE 250- GROUNDING AND BONDING (c) If multiconductor cables are paralleled in the same raceway, auxiliary gutter, or cable tray, a single equipment grounding conductor that is sized in accordance with 250.122 shall be permitted in combination with the equipment grounding conductors provided within the multiconductor cables and shall aU be connected together. (d) Equipment grounding conductors installed in cable shall meet the nu nun um requirements of trays 392.lO(B)(l )(c) . Cable trays complying with 392.60 (B), metal raceways in accordance with 250.118, or auxilia1y gutters shall be permitted as the equipment grounding condu cto1·.

system unless the opening of the cutout or switch disconnects all sources of energy. 250.126 Identification of Wiring Device Terminals. The terminal for the connection of the equipment grounding conductor shall b e identified b y one of the fo llowing: (1) (2) (3)

(G) Feeder Taps. Equipment grounding conductors installed with feeder taps shall not be smaller than shown in Table 250.122 based on the rating of the overcurrent device ahead of the feeder on the supply side ahead of the tap but shall not be required to be large r than the tap conductors. 250.124 Equjpment Groundillg Conductor Continuity. (A) Separable Connections. Separable connections such as those provided in drawout equipment or attachment plugs and mating connectors and receptacles shall provide for first·make , last-break of the equipment grounding conductor. First-make , last-break shall not be required where interlocked equipment, plugs, receptacles, and connectors preclude energization wid1out grounding continuity.

250.130

A green, not readily removable terminal screw with a hexagonal head. A green, hexagonal, not readily removable terminal nut. A green pressure wire connector. If the terminal for the equipment grounding conductor is not visible, the conductor en trance ho le shall be marked with the word green or ground, the letters G or GR, a grounding symbol, or otherwise identified by a distinctive green color. If ilie terminal for the equipment grounding conductor is readily removable, the area adjacent to the termina l sha ll be similarly marked. Informational Note: See I nformational Note Figure 250.126.

Informational Note Figure 250. 126 One Example of a Symbol Used to Identify the Groundillg Termination Point for an Equipment Groundillg Conductor.

(B) Switches. No automatic cutout or switch shall be placed in ilie equipment grounding conductor of a p1·emises wiring

Part VII. Methods of Equipment Groundillg Conductor Connections

Table 250.122 Minjmum Size Equjpment Grounrung Conductors for Groundillg Raceway and Equipment

250.130 Equipment Groundillg Conductor Connections. Equipm ent grounding conductor connections at the source of separately derived systems shall be made in accordance with 250.30(A)(l). Equipment grounding conductor connectio ns at service equipment shall b e made as indicated in 250.130(A) o r (B) . For replacement of non-grounding-type receptacles with grounding-type receptacles and for branch-circuit extensions only in existing installations that do not have an equipment grounding conductor in the bran ch c i1·cuit, connections sha ll be permitted as indicated in 250.130(C) .

Rating or Setting of Automatic Overcurrent Device in Circuit Ahead of Equipment, Conduit, etc., Not Exceeding (Amperes)

Size (AWG or kcmil)

Copper

Aluminum or Copper-Clad Aluminum*

15 20 60 100

14 12

12

IO

8 6

200 300 400

6 4 3

4 2

(B) For Ungrounded Systems. The connection shall be made by bonding the equipment grounding conductor to the grounding e lectrode conductor.

500 600 800

2 1/ 0

1/ 0 2/ 0 3/ 0

1000 1200 1600

2/ 0 3/ 0 4/ 0

4/0 250 350

(C) Nongrouniling Receptacle Replacement or Branch Circuit Extensions. The equipment groundi ng conductor of a grounding-type receptacle or a branch-circuit extension shal l be permitted to be connected to any of the following:

2000 2500 3000

250 350 400

400 600 600

(3)

4000 5000 6000

500 700 800

750 1250 1250

(4)

8

l

lO

Note: Whe re necessary to comply with 250.4(A)(5) or (B) (4), the equipment grounding conductor shall be sized larger than given in this table . *See instal lation restrictions in 250.120.

2020 Edition

NATIONAL ELECTRICAL CODE

(A) For Grounded Systems. The connection shall b e made by bonding the equipment grounding conductor to the grounded service conductor and the grounding e lectrode conductor.

(1) (2)

(5)

Any accessible point on the grounding e lectrode syste m as described in 250.50 Any accessible point o n the grounding e lectrode conductor The equipment grounding termin al bar withi n the enclostu-e where d1e branch circuit for the receptacle or branch circuit orig inates An equipme n t grounding conductor that is part of another branch c ircuit that originates from ilie enclosure where me branch circuit for the receptacle or branch circu it originates For grounded systems, th e grounded service conductor within d1e service equipment enclosure

70-133

250.132 (6)

ARTICLE 250- GROUNDING AND BONDING

For ungrounded systems, the grounding terminal bar within the service equipment enclostu-e Informational Note: See 406.4( 0 ) for the use of a g round-fault circuit-interrupting type of receptacle. ·

250.132 Short Sections of Raceway. Isolated sections of metal raceway or cable armor, if required to be connected to an equipment grow1ding conductor, shal l be connected in accordance with 250.1 34. 250.134 Equipment Fastened in Place or Connected by Permanent Wiring Methods (Fixed). Unless connected to the grow1ded circuit conductor as permitted by 250.32, 250.140, and 250.142, non-current-carrying metal parts of equipment, race\vays, and other enclosures, if grounded, shall be connected to an equipment grounding conductor by one of the following methods: (1)

By connecting to any of the equipment grounding conductors permitted by 250 .118(2) through (14) By connecting to an equipment grounding conductor of the wire type that is contained within the same raceway, contained within the same cable, or otherwise run with the circ uit conductors

(2)

Exception No. 1: As provided in 250.130(C), the equipment grounding conductor shall be permitted to be run separately frmn the circuit conductors. Exception No. 2: For de circuits, the equipment grounding conductor shall be perrnitted to be run separately fmrn the circuit conductors Informational Note No. 1: See 250.102 and 250.168 for equip ment bonding jumper requirements. Informational Note No. 2: See 400.10 for use of flexible cords and flexible cables for fixed equipment.

250.136 Equipment Secured to Grounded Metal Supports. Electrical equipment secured to and in electrical contact with a metal rack o r structure provided fo r its support shal.l be permitted to be considered as be ing connected to an equipment grounding conductor if the metal rack or structure is connected to an equipment grounding conductor by one of the means indicated in 250.1 34. 250.138 Cord-and-Plug-Connected Equipment. Non-currentcarrying metal parts of cord-and-p lug-connected equipment, if 1-equired to be connected to an equipme n t grounding conductor, shall be connected by one of the methods in 250.1 38(A) or (B) .

(A) By Means of an Equipment Grounding Conductor. By means of an equipment grounding condu ctor run with the power supply conductors in a cable assembly or flexible cord properly terminated in a grounding-type attachment plug with one fixed grounding contact. E-.:ception: The grounding contacting pole of grounding-type plug-in groundfaull circuit interrupters shall be permitted to be of the rnovable, self-restoring type on circuits ofJerating at not over 150 volls between any two conducton or over 150 volts between any conductor and ground.

(B) By Means of a Separate Flexible Wire or Strap. By means of a separate flexible wire or strap, insulated or bare, connected to an equipment grounding conductor, and pmtected as we ll as practicable ag-ainst physical damage, where part of equipment.

70-134

250.140 Frames of Ranges and Clothes Dryers. Frames of elecu-ic ranges, wall-mow1ted ovens, counter-mounted cooki ng units, clothes dryers, and outlet or junction boxes that are part of the circuit for these appliances shall be connected to the equipment grounding conductor in the manner specified by 250 .1 34 or 250.138. Exception: F.Td = dielecu-ic loss temperature 1-ise Rd, = de resistance of conductor at temperature, 1: Y, = component ac resistance resulting from skin effect a nd proximity effect R,0 = effective thermal resistance betwee n conduc to r a nd surrounding ambient

1:

Informational Note: The d ielectric loss temperature rise (~ 7~) is negligible for single circuit extruded d ielectric cables rated below 46 kilovolts.

Where the condition of maintenance and supervision enS1.nr1s that only qualified personnel install and service the installation. Conductors shall have insulation 1r1sistant to el.ect1ic discharge and S1.njace tracking, or the inS1.llated conducto1{s) shall be

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NATIONAL ELECTRICAL CODE

2020 Edi tion

311.60

ARTICLE 311- MEDIUM VOLTAGE CONDUCTORS AND CABLE (C) Tables. Ampacities for conductors rated 2001 volts to 35,000 volts shall be as specified in Table 311.60(C) (67) through Table 311.60(C) (86) . Ampacities for ambient temperanll"es other than those specified in the ampacity tables shall be corrected in accordance with 311.60(D)(4) . Informational Note No. 1: For ampacities caJculated in accordance with 31 l.60(A), reference IEEE 835, Standard Power Cable Ampacity Tabli!s, and the references therein for availability of all factors and constants. Informational Note No. 2: Ampacities provided by this section do not take voltage drop into consideration. See 210.19(A), lnformarional Note No. 4, for branch circuits and 215.2(A) , Informational Note No. 2, for feeders. (D) Ampacity Adjustment. (1) Grounded Shields. Ampacities shown in Table 311 .60(C) (69), Table 311.60(C)(70), Table 311 .60(C)(81), and Table 3 11.60(C) (82) shall apply for cables with shields grounded at one point only. Where shields for these cables are grounded at m01·e than one point, ampacities shall be adjusted to take into consideration the heating due to shield currents. Informational Note: Tables other than those listed contain the ampacity of cables with shields grounded at multiple points.

Table 31 l.60(C)(67) Ampacities of Insulated Single Copper Conductor Cables Triplexed in Air

Table 311.60(C)(68) Ampacities oflnsulated Single Aluminum Conductor Cables Triplexed in Air Temperature Rating of Conductor 2001-5000 Volts Ampacity Conductor Size 90°c (AWG or (194°F) kcmil) Type MV-90

5001-35,000 Volts Ampacity

l05°c (221°F) Type MV-105

90°c (194°F) TypeMV-90

105°c (221°F) Type MV-105

8 6 4 2

50 70 90 125 145

57 77 100 135 160

75 100 130 150

84 llO 150 175

1/ 0 2/ 0 3/ 0 4/ 0

170 195 225 265

185 215 250 290

175 200 230 270

200 230 265 305

250 295 325 300 335 350 365 405 370 415 460 510 460 515 500 750 600 665 590 660 1000 715 800 700 780 Note: Refer to 311.60(E) for basis ofampacities, 31 1.IO(A) for conductor maximum operating temperature and application, and 311.60(D) (4) for the ampacity correction factors where the ambient air temperature is other than 40°C (104°F).

Temperature Rating of Conductor 2001-5000 Volts Ampacity

5001-35,000 Volts Ampacity

105°C (221 °F) Type MV-105

90°c (194°F) Type MV-90

l05°c (221°F) Type MV-105

l

65 90 120 160 185

74 99 130 175 205

100 130 170 195

llO 140 195 225

1/ 0 2/ 0 3/ 0 4/ 0

215 250 290 335

240 275 320 375

225 260 300 345

255 295 340 390

Conductor Size 90°c (AWGor (194°F) kcmil) Type MV-90 8 6 4 2

250 375 415 380 430 350 465 515 470 525 500 580 645 580 650 750 750 730 820 835 1000 880 980 850 950 Note: Refer to 31 l.60(E) for the basis ofampacities, 311.IO(A) for conductor maximum operating temperature and application, and 3ll .60(D) (4) for the ampacity correction factors where the ambient air temperature is other than 40°C (104°F).

2020 Edition

NATIONAL ELECTRICAL CODE

(2) Burial Depth. v\There the burial depth of direct burial or electrical duct bank circuits is modified from t he values shown in a figure or table, a mpacities shall be permitted to be modified as indicated in 311.60(D) (2) (a) and (D) (2) (b) . No ampacity adjustments shall be required wh ere the burial depth is decreased. (a) Where burial depths are increased in part(s) of an electrical duct run, a decrease in ampacity of the conductors shall not be required, provided the total length of parts of the duct run increased in depth is less than 25 percent of the total run length. (b) Where burial depths are deeper than sh own in a specific underground ampacity table or figure, an ampacity derating factor of 6 percent per 300 mm (1 ft) increase in depth for all values of rho sh al 1 be permitted. (3) Electrical Ducts Entering Equipment Enclosures. At locations where e lectrical ducts e nter equipment enclosw·es from underground, spacing benveen such ducts, as shown in Figure 31 l.60(D) (3), shall be permitted to be reduced without requiring the ampacity of conductors therein to be 1·educed.

70- 169

311.60

ARTICLE 311 -MEDIUM VOLTAGE CONDUCTORS AND CABLE

Table 31 l.60(C)(69) Ampacities of Insulated Single Copper Conductor Isolated in Air

Table 311.60(C)(70) Ampacities of Insulated Single Aluminum Conductor Isolated in Air

Temperature Rating of Conductor 2001-5000 Volts Ampacity

500115,000 Volts Amp a city

Conductor 90°c 105°C 90°c l05°c (194°F) (221°F) (194°F) (221°F) Size (AWG Type Type Type Type or kcmil) MV-90 MV-105 MV-90 MV-105 8 6 4 2

15,00135 ,000 Volts Ampacity 90°c 105°c (194°F) (221 OF) Type Type MV-90 MV-105

83 110 145 190 225

93 120 160 215 250

llO 150 195 225

125 165 215 250

225

0 0 0 0

260 300 345 400

290 330 385 445

260 300 345 400

290 335 385 445

250 350 500 750

445 550 695 900

495 615 775 1000

445 550 685 885

495 610 765 990

1/ 2/ 3/ 4/

Temperature Rating of Conductor 2001-5000 Volts Ampacity

500115,000 Volts Ampacity

Conductor 90°c 105°c 90°c 105°C (194°F) (221 °F) (194°F) (221°F) Size (AWG Type Type Type Type orkcmil) MV-90 MV-105 MV-90 MV-105

15,00135,000 Volts Amp a city 90°c 105°C (194°F) (221 °F) Type Type MV-90 MV-105

250

8 6 4 2 1

64 85 115 150 175

71 95 125 165 195

87 115 150 175

97 130 170 195

175

195

260 300 345 395

290 330 380 445

1/ 0 2/ 0 3/ 0 4/ 0

200 230 270 310

225 260 300 350

200 235 270 310

225 260 300 350

200 230 270 310

225 260 300 345

440 545 680 870

490 605 755 970

250 350 500 750

345 430 545 710

385 480 605 790

345 430 535 700

385 480 600 780

345 430 530 685

380 475 590 765

1000 1075 1200 1060 ll 85 1040 1160 1250 1230 1370 1210 1350 ll85 1320 1500 1500 1365 1525 1345 1315 1465 1495 1470 1750 1640 1430 1595 1665 2000 1605 1790 1575 1755 1535 1710 Note: Refer to 31 l.60(E) for the basis ofampacities, 311.lO(A) for conductor maximum operating temperature and application, and 311.60(0 ) (4) for the ampacity correction factors where the ambient air temperature is other than 40°C (104°F).

1000 855 950 840 940 825 920 1250 980 1095 970 1080 950 1055 1215 1500 ll05 1230 1085 1060 1180 1215 1750 1355 ll95 1335 ll65 1300 2000 1320 1475 1295 1445 1265 1410 Note: Refer to 3ll.60(E) for t he basis ofampacities, 311.lO(A) for conductor maximum operating temperature and application, and 31 1.60 (0 ) (4) for the ampacity correction factors where the ambient air temperature is other than 400C ( l04°F).

(4) Ambient Temperature Correction. Ampacities for ambient temperatures other than those specified in the ampacity tables shall be corrected in accordance with Table 311.60( D) (4) or shall be permitted to be calculated using the following equation:

(2)

[31 l.60(D)(4)]

I' = I wh ere: I' = ampacity corrected for a mbient temperature I= ampacity shown in the table for 1: and 7~, 0 = temperature rating of conductor ( C) 1: ' = new ambient temperature (°C) = ambient temperature u sed in the table (°C)

1: 1:

(E) Ampacity in Air. Ampaciti.es for conductors and cables in air shall be as specified in Table 31 l. 60( C) (67) through Table 311.60 (C) (76) . Ampaciti.es shall be based on the following: (1)

Ambient a ir temperature of 40°C (104°F) Informational Note: See 31 1.60( 0 ) (4) where the ambient air temperature is other than 40°C (104°F).

(F) Ampacity in Underground Electrical Ducts and Direct Buried in Earth. Ampac ities for conductors and cables in underground electrical ducts and direct buried in earth shall b e as specified in Tabl e 31 l.60 (C) (77) throu gh Table 31 l .60(C) (86) . Arnpacities sh a ll be based on the fo llowing: (1) (2) (3) (4) (5) (6) (7)

Ambient earth temperature of 2Q°C (68°F) Arrangement in accordan ce with Figure 31 l.60(D) (3) 100 percent load factor Thet-mal resistance (Rho) of90 Conductor temperatures 90°C (l 94°F) and 105 °C (221°F) Minimum burial depths to the top elecu·ical ducts ot· cables shall be in accordance with 300.50. Maximum depth to the top of elecu·ical duct banks shall be 750 mm (30 in. ), an d m aximum depd1 to the top of direct-buried cables shall be 900 mm (36 in.).

Conductor temperatures of 90°C (194°F) and 105°C ( 221 °F )

70-170

NATIONAL ELECTRICAL CODE

2020 Edi tion

311.60

ARTICLE 311 - MEDIUM VOLTAGE CONDUCT O RS AND CABLE Table 31 l.60(C)(71) Ampacities of an Insulated Three-Conductor Copper Cable Isolated in Air

Table 311.60(C) (73) Ampacities of an Insulated Triplexed or Three Single-Conduc tor Copper Cables in Isolated Conduit in Air

Temperature Rating of Conductor 2001- 5000 Volts Ampacity Conductor Size (AWG

or kcmil) 8 6 4 2 l

1/ 0 2/0 3/0 4/0

Temperature Rating of Conductor

5001-35,000 Volts Ampacity

90°C (194°F) Type MV-90

105°C (221°F) Type MV-105

90°C (194°F) Type MV-90

105°C (221 OF) Type MV-105

59 79 105 140 160

66 88 115 154 180

93 120 165 185

105 135 185 210

185 215 250 285

205 240 280 320

215 245 285 325

240 275 315 360

2001- 5000 Volts Ampacity 90°C (194°F ) Type MV-90

105°C (221 °F) T ype MV-105

90°C (194°F) Type MV-90

105°C (221 °F ) Type MV-105

8 6 4 2

55 75 97 130 155

61 84 110 145 175

83

llO 150 170

93 120 165 190

1/ 0 2/0 3/0 4/ 0

180 205 240 280

200 225 270 305

195 225 260 295

215 255 290 330

Conductor Size (AWG

orkcmil)

250 320 355 360 400 395 440 435 490 350 500 485 545 535 600 750 615 685 670 745 1000 705 790 770 860 Note: Refer to 31 l.60(E) for the basis ofampacities, 311.lO(A) for conductor maxim tun operating temperature and application, and 311.60(0) (4) for the ampacity correction factors where the ambient air temperature is other than 40°C (104°F).

5001-35,000 Volts Ampacity

250 315 355 330 365 350 385 430 395 440 500 475 530 480 535 750 600 665 585 655 1000 690 770 675 755 Note: Refer to 311.60(E) for the basis ofampacities, 311.lO(A) for conductor maximum operating temperature and application, and 311.60(0 ) (4) for the arnpacity correction factors where the ambient air temperature is other than 40°C ( 104°F).

Table 31 l.60(C)(72) Ampacities of an Insulated Three-Conductor Aluminum Cable Is olated in Air Temperature Rating o f Conductor 2001-5000 Volts Ampacity

5001-35,000 Volts Ampacity

90°C (194°F) T ype MV-90

105°C (221°F) Type MV-105

90°C (194°F ) Type MV-90

105°C (221 OF) Type MV-105

8 6 4 2

46 61 81 110 125

51 68 90 120 140

72 95 125 145

80 105 145 165

1/ 0 2/ 0

145 170

160 185

170 190

185 215

3/0 4/0

195 225

215 250

220 255

245 285

Conductor Size (AWG

or kcmil)

250 280 280 315 250 350 310 345 345 385 500 385 430 425 475 750 495 540 550 600 585 650 635 705 1000 Note: Refer to 31l.60(E) for the basis ofampacities, 311.lO(A) for conductor maxim tun operating temperatrn·e and application , and 311.60(0 ) (4) for the ampacity correction factors where the ambient air temperature is other than 40°C (104°F).

2020 Edition

NATIONAL ELECTRICAL CODE

70- 171

311.60

ARTICLE 311 -MEDIUM VOLTAGE CONDUCTO RS AND CABLE

Table 31 l.60(C)(74) Ampacities of an Insulated Triplex ed or Three Single-Conductor Aluminum Cables in Isola ted Conduit in Air

Table 311.60(C)(76) Ampacities of an Insulate d Three-Conductor Aluminum Cable in Isolated Conduit in Air Temperature Rating of Conductor

Temperature Rating of Conductor 2001-5000 Volts Ampacity

5001- 35,000 Volts Ampacity

90°c (194°F) Type MV-90

105°c (221 °F) Type MV-105

90°c (194°F ) Type MV-90

105°c (221 OF) Type MV-105

8 6 4 2

43 58 76 100 120

48 65 85 115 135

65 84 115 130

72 94 130 150

1/ 0 2/0 3/0 4/0

140 160 ] 90 215

155 175 210 240

150 175 200 230

170 200 225 260

Conductor Size (AWG or kcmil)

250 250 280 255 290 350 305 340 310 350 500 380 425 385 430 490 750 545 485 540 1000 580 645 565 640 Note: Refer to 31l.60(E) for the basis ofampacities, 311.lO(A) for conductor maximum operating temperature and application, and 311.60(0) (4) for the ampacity correction factors where the ambient air temperature is other than 40°C (104°F).

2001-5000 Volts Ampacity Conductor Size (AWG or kcmil)

5001-35,000 Volts Ampacily

90°c (194°F ) Type MV-90

105°c (221 °F) Type MV-105

90°c (194°F) Type MV-90

105°C (221 °F ) Type MV-105

8 6 4 2 1

41 53 71 96 llO

46 59 79 105 125

64 84 115 130

71 94 125 145

1/0 2/0 3/0 4/0

130 150 170 200

145 165 190 225

150 170 19.5 225

170 190 220 255

250 220 245 250 280 350 275 305 305 340 425 340 500 380 380 750 430 480 470 520 1000 505 560 550 615 Note: Refer to 311.60(E) for the basis ofampacities, 311.lO(A) for conductor maximum operating temperature and application, and 311.60(0 ) (4) for the ampacity correction factors where the ambient air temperature is other than 40°C (104°F).

Table 31 l.60(C)(75) Ampacities of an Insulated Three-Conductor Copper Cable in Isolated Conduit in Air Temperature Rating of Conductor 2001- 5000 Volts Ampacily 90°c ( 194°F) Type MV-90

105°c (22 1°F) Type MV-105 58

I

52 69 91 125 140

1/ 0 2/0 3/0 4/0

165 190 220 255

Conductor Size (AWG or kcmil) 8 6 4 2

5001- 35,000 Volts Ampacity 90°c (194°F ) Type MV-90

105°c (221 OF) Type MV-105

100 135 155

83 105 145 165

92 120 165 185

185 210 245 285

195 220 250 290

215 245 280 320

77

315 315 350 250 280 430 350 350 390 385 500 470 475 425 525 750 525 585 570 635 590 660 650 725 1000 Note: Refer to 31l.60(E) for the basis ofampacities, 311.lO(A) for conductor maximum operating temperature and application, and 311.60(0) (4) for the ampacity correction factors where the ambient air temperature is other than 40°C (104°F).

70-172

NATIONAL ELECTRICAL CODE

2020 Edi tion

311.60

ARTICLE 311 - MEDIUM VOLTAGE CONDUCTORS AND CABLE Table 311.60( C)(77) Ampacities of Three Single-Insulated Copper Conductors in Underground Electrical Ducts (Three Conductors per Electrical Duct)

Table 311.60(C)(78) Ampacities of Three Single-Insulated Aluminum Conductors in Underground Electrical Ducts (Three Conductors per Electrical Duct)

Tempernture Rating of Conductor 2001-5000 Volts Ampacity Conductor Size (AWG

or kcmil)

90°c (l94°F) Type MV-90

l05°c (221OF) Type MV-105

Temperature Rating of Conductor

5001-35,000 Volts Ampacity 90°c (194°F) Type MV-90

l05°c (221°F) Type MV-105

One Circuit [See Figure 311.60(D)(3), Detail 1.]

Conductor Size (AWG

or kcmil)

90°c (194°F) Type MV-90

l05°c (221°F) Type MV-105

5001- 35,000 Volts Ampacity 90°c (l94°F) Type MV-90

l05°c (221°F) Type MV-105

One Circuit [See Figure 311.60(D)(3) , Detail 1.] 64 85

145 170

69 92 120 155 180

90 115 155 175

97 125 165 185

1/ 0 2/0 3/0 4/0

195 220 250 290

210 235 270 310

200 230 260 295

250 350 500 750 1000

320 385 470 585 670

345 415 505 630 720

325 390 465 565 640

8 6 4 2

2001- 5000 Volts Ampacity

no

l

50 66 86 115 130

93 125 140

70 91 120 135

75 98 130 145

215 245 275 315

1/ 0 2/0 3/ 0 4/ 0

150 170 195 225

160 185 210 245

155 175 200 230

165 190 215 245

345 415 500 610 690

250 350 500 750 1000

2:')0 305 370 470 545

270 325 400 505 590

250 305 370 455 525

270 330 400 490 565

Three Circuits [See Figure 311.60(D)(3), Detail 2.]

8 6 4 2

54 71

Three Circuits [See Figure 31 l.60(D) (3), Detail 2.] 8 6 4 2

44 57 74 96 110

47 61 80 105 120

60 77 100 llO

65 83 105 120

175 200 225 255

1/ 0 2/0 3/0 4/0

125 145 160 185

135 155 175 200

125 145 165 185

140 155 175 200

280 330 395 475 535

250 350 500 750 1000

205 245 295 370 425

220 265 320 395 460

200 245 290 355 405

220 260 315 385 440

8 6 4 2

56 73 95 125 140

60 79 100 130 150

77 99 130 145

83 105 135 155

l/O 2/0 3/0 4/0

160 185 210 235

175 195 225 255

165 185 210 240

250 350 500 750 1000

260 315 375 460 525

280 335 405 495 565

260 310 370 440 49.5

Six Circuits [See Figure 311.60(D)(3), Detail 3.]

Six Circuits [See Figure 3 1l.60(D) (3), Detail 3.]

8 6 4 2

48 62 80 105 115

52 67 86 110 125

64 82 105 120

68 88 J1 5 125

8 6 4 2 1

38 48 62 80 91

41 52 67 86 98

50 64 80 90

54 69 88 99

1/0 2/0 3/0 4/ 0

135 150 170 195

145 160 185 210

135 150 170 190

J45 165 185 205

1/0 2/0 3/0 4/ 0

105 115 135 150

110 125 145 165

105 115 130 150

110 125 145 160

250 225 225 210 210 350 250 270 245 265 500 300 325 290 310 750 375 395 365 350 1000 410 445 390 415 Note: Refer tO 3 1 l.60 (F) for basis ofampacities a nd Table 31 1.lO(A) for th e temperature rating of the conductor.

2020 Edition

NATIONAL ELECTRICAL CODE

175 250 165 180 165 350 195 210 195 210 500 240 255 230 250 750 290 315 280 305 1000 335 360 320 345 Note: Referco 3 1 l.60(F) fo r basis of ampacicies and Table 3 11.lO(A) fo r the temperanire rating of th e conductor.

70- 173

311.60

ARTICLE 311 - MEDIUM VOLTAGE CONDUCTORS AND CABLE

Table 311.60( C)(79) Ampacities of Three Insulated Copper Conductors Cabled Within an Overall Covering (Three-Conductor Cable) in Underground Electrical Ducts (One Cable per Electrical Duct)

Table 311.60(C)(80) Ampacities of Three Insulated Aluminum Conductors Cabled Within an Overall Covering (Three-Conductor Cable) in Underground Electrical Ducts (One Cable per Electrical Duct)

Temperature Rating of Conductor 2001- 5000 Volts Amp a city Conductor

Size (AWG

or kcmil)

90' C (194' F) Type MV·90

105' C (221 ' F) Type MV·l05

Temperature Rating of Couductor

5001- 35,000 Volts Ampacity 90' C (l94'F) Type MV·90

105' C (221 ' F) Type MV·l05

One Circuit [See Figure 3ll.60(D)(3), Detail l.)

2001- 5000 Volts Ampacity Conductor Size

90' C (l94' F) Type MV·90

l05' C (221°F) Type MV·l05

50 66 86

I

46 61 80 105 120

(AWG

or kcmil)

5001- 35,000 Volts Ampacity 90' C (l94' F) Type MV·90

l05' C (22l' F) Type MV·l05

130

69 89 11 5 135

74 96 125 145

One Circuit [See Figure 3l l.60(D)(3), Detail l.)

I

59 78 100 135 155

64 84 ll O 145 165

88 115 150 170

95 125 160 185

1/0 2/ 0 3/0 4/ 0

175 200 230 265

190 220 250 285

195 220 250 285

2 10 235 270 305

1/ 0 2/ 0 3/ 0 4/ 0

140 160 180 205

150 170 195 220

150 170 195 220

165 185 210 240

250 350 500 750 1000

290 355 430 530 600

3 15 380 460 570 645

3 10 375 450 545 6 15

335 400 485 585 660

250 350 500 750 1000

230 280 340 425 495

245 310 365 460 535

245 295 355 440 510

265 315 385 475 545

8 6 4 2

41 54 70 90 105

44 58 75 97 llO

59 75 100 11 0

64 81 10.'> 120

8 6 4 2

Three Circuits [See Figure 3 ll.60(D)(3), Detail 2.)

8 6 4 2

ll O

Three Grcuits [See Figure 3ll.60(D)(3), Detail 2.)

8 6 4 2

53 69 89 11 5 135

:'>7 74 96 125 145

75 97 125 140

81 105 135 155

1/ 0 2/ 0 3/ 0 4/ 0

150 170 195 225

165 185 21() 240

160 185 205 230

175 195 220 250

1/ 0 2/ 0 3/ 0 4/ 0

120 135 155 175

125 145 165 185

125 140 160 180

135 155 175 195

250 350 500 750 1000

245 295 355 430 48.?

265 315 380 465 520

255 305 360 430 485

270 325 385 465 515

250 350 500 750 1000

190 230 280 345 400

205 250 300 375 430

200 240 285 350 400

215 255 30.'> 375 430

I

36 46 60 77 87

39 50 65 83 94

49 63 80 90

53 68 86 98

1/ 0 2/ 0 3/0 4/ 0

99 llO 130 145

105 120 140 155

105 ll 5 130 150

11 0 125 140 160

Six Circuits [See Figure 3l l.60(D) (3), Detail 3.) 8 6 4 2

Six Circuits [See Figure 3ll.60(D) (3), Detail 3.)

I

46 60 77 98 110

50 65 83 105 120

63 81 105 115

68 87 11 0 125

1/ 0 2/ 0 3/0 4/ 0

125 145 165 185

135 1:'>5 175 200

130 150 170 190

145 160 180 200

250 350 500 750 1000

200 220 20:> 220 240 270 245 275 290 310 290 305 340 36:'> 350 375 420 405 390 380 Note: Refer to 31 l.60 (F) for basis of a m pacities a nd Table 31 1.I O(A) fo r the temperature rating of the cond uctor.

70-174

8 6 4 2

250 160 170 160 170 350 190 205 190 205 500 230 245 230 245 275 295 750 280 305 320 345 315 1000 335 Note: Refer to 311.60 (F) fo r basis ofampacities and Table 3 11.lO(A) fo r the tem perature rating of th e conductor.

NATIONAL EL ECTRICAL CODE

2020 Edi tion

ARTICLE 311 - MEDIUM VOLTAGE CONDUCTORS AND CABLE Table 31 l.60(C)(81) Ampacities of Single Insulated Copper Conductors Directly Buried in Earth

Table 31 l.60(C) (82) Ampacities of Single Insulated Aluminum Conductors Directly Buried in Earth

Temperature Rating of Conductor 2001-5000 Volts Ampacity Conductor Size (AWG

or kcmil)

90°C (194°F) Type MV-90

105°C (221 °F) Type MV-105

Temperature Rating of Conductor

5001-35,000 Volts Ampacity 90°C (l94°F) Type MV-90

311.60

105°C (221°F) Type MV-105

One Circuit, Three Conductors [See Figure 31 l.60(D)(3) , Detail 9.)

2001-5000 Volts Ampacity Conductor Size (AWG

or kcmil)

90°C (l94°F) Type MV-90

5001-35,000 Volts Ampacity

l05°C (221°F) Type MV-105

90°C ( l94°F) Type MV-90

105°C (221°F) Type MV-105

100 130 165 185

140 175 200

One Circuit, Three Conductors [See Figure 311.60(D) (3), Detail 9.)

8 6 4 2

llO 140 180 230 260

ll5 150 195 250 280

130 170 210 240

140 180 225 260

8 6 4 2 1

140 180 205

90 ll5 150 195 220

1/ 0 2/ 0 3/ 0 4/ 0

295 335 385 435

320 365 415 465

275 310 355 405

295 335 380 435

1/ 0 2/ 0 3/ 0 4/ 0

230 265 300 340

250 285 320 365

215 245 275 315

230 260 295 340

250 350 500 750 1000

470 570 690 845 980

510 615 745 910 1055

440 535 650 805 930

475 575 700 865 1005

250 350 500 750 1000

370 445 540 665 780

395 480 580 720 840

345 415 510 635 740

370 450 545 680 795

Two Circuits, Six Conductors [See Figure 311.60(D)(3), Detail 10.)

85 IIO

IIO

Two Circuits, Six Conductors [See Figure 311.60(D)(3),Detail 10.)

8 6 4 2

100 130 165 215 240

110 140 180 230 260

120 160 195 225

130 170 210 240

1/ 0 2/ 0 3/ 0 4/ 0

275 310 355 400

295 335 380 430

255 290 330 375

8 6 4 2

80 100 130 165 190

140 180 200

95 125 155 175

100 130 165 190

275 315 355 405

1/ 0 2/ 0 3/ 0 4/ 0

215 245 275 310

230 260 295 335

200 225 255 290

215 245 275 315

435 470 410 440 520 560 495 530 630 680 600 645 775 740 795 835 890 960 855 920 Note: Refer to 31 l.60(F) for basis ofampacities and Table 31 l.IO(A)

250 350 500 750 1000

340 365 320 345 410 440 385 415 495 530 470 505 610 580 625 655 710 765 680 730 Note: Refer to 311.60(F) for basis ofampacities and Table 311.IO(A)

for the temperature rating of the conductor.

for the temperamre rating of the conductor.

250 350 500 750 1000

2020 Edition

NATIONAL ELECTRICAL CODE

85 llO

70-175

311.60

ARTICLE 311 -MEDIUM VOLTAGE CONDUCTO RS AND CABLE

Table 31 l.60(C)(83) Ampacities of Three Insulated Copper Conductors Cabled Within an Overall Covering (Three-Conductor Cable), Directly Buried in Earth

Table 311.60(C)(84) Ampacities of Three Insulated Aluminum Conductors Cabled Within an Overall Covering (Three-Conductor Cable), Directly Buried in Earth

Temperature Rating of Conductor 2001- 5000 Volts Ampacity Conductor Size (AWG or kcmil)

90°c (194°F) Type MV·90

105°c (221°F) Type MV· l05

5001- 35,000 Volts Ampacity 90°c (194°F) Type MV-90

105°C (221°F) Type MV-105

One Circuit [See Figure 311.60(D)(3), Detail 5.]

2001- 5000 Volts Ampacity Conductor Size (AWG or kcmil)

90°c (194°F) Type MV-90

5001- 35,000 Volts Ampacity

105°c (221°F) Type MV-105

90°c (194°F) Type MV-90

105°c (221 °F) Type MV-105

One Circuit [See Figure 31 l.60(D) (3), Detail 5.] 8 6 4 2

65 80 105 140 155

70 88 115 150 170

90 115 145 165

95 125 155 175

255 290 330 375

1/ 0 2/0 3/0 4/0

180 205 230 260

190 220 250 280

185 210 240 270

200 225 260 295

410 495 590 720 810

250 350 500 750 1000

285 345 420 520 600

310 375 450 560 650

300 360 435 540 620

320 390 470 580 665

l

60 75 100 130 145

66 83 110 140 155

80 105 135 150

95 115 145 165

1/0 2/0 3/0 4/0

165 190 215 245

180 205 230 260

170 195 220 250

185 210 240 270

8 6 4 2

85 105 135 180 200

89 ll 5 150 190 215

115 145 185 210

120 155 200 225

1/ 0 2/0 3/0 4/0

230 260 295 335

245 280 320 360

240 270 305 350

250 350 500 750 1000

365 440 530 650 730

395 475 570 700 785

380 460 550 665 750

Two Circuits [See Figure 31 l.60(D)(3), Detail 6.]

Two Circuits [See Figure 3 l l.60(D) (3), Detail 6.]

8 6 4 2 1

80 100 130 165 185

84 105 140 180 200

105 135 170 195

115 145 185 210

1/ 0 2/0 3/0 4/0

215 240 275 310

230 260 295 335

220 250 280 320

235 270 305 345

250 340 365 350 375 350 410 440 420 450 500 490 500 525 535 750 595 640 605 650 1000 665 715 675 730 Note: Refer to 31 l.60(F) for basis of ampacities and Table 311.1 O(A) for the temperature rating of the conductor.

70-176

Temperature Rating of Conductor

8 6 4 2

250 265 285 275 295 350 320 345 330 355 415 500 385 395 425 750 480 515 485 525 1000 550 590 560 600 Note: Refer to 3ll.60( F) for basis ofampacities and Table 311.JO(A) for the temperature rating of the conductor.

NATIONAL ELECTRICAL CODE

2020 Edi tion

311.60

ARTICLE 311 - MEDIUM VOLTAGE CONDUCTORS AND CABLE Table 31 l.60(C)(85) Ampacities of Three Triplexed Single Insulated Copper Conductors Directly Buried in F.arth

Table 311.60(C)(86) Ampacities of Three Triplexed Single Insulated Aluminum Conductors Directly Buried in Earth

Temperature Rating of Conductor 200 l-5000 Volts Ampacity Conductor Size (AWG

orkcmil)

90°c (l94°F) Type MV-90

105°C (221°F) Type MV-105

Temperature Rating of Conductor

5001-35,000 Volts Ampacity 90°c (194°F) Type MV-90

105°C (221°F) Type MV-105

One Circuit, Three Conductors [See Figure 31 l.60(D)(3) , Detail 7 .]

2001-5000 Volts Ampacity Conductor Size (AWG

or kcmil)

90°c (l94°F) Type MV-90

5001-35,000 Volts Ampacity

105°c (221°F) Type MV-105

90°c (l 94°F) Type MV-90

105°C (221°F) Type MV-105

One Circuit, Three Conductors [See Figure 311.60(D) (3), Detail 7.)

8 6 4 2

90 120 150 195 225

95 130 165 205 240

115 150 190 215

120 160 205 230

8 6 4 2 1

70 90 120 155 175

75 100 130 165 190

90 115 145 165

95 125 155 175

0 0 0 0

255 290 330 375

270 310 360 405

245 275 315 360

260 295 340 385

1/ 0 2/ 0 3/ 0 4/ 0

200 225 255 290

210 240 275 310

190 215 245 280

205 230 265 305

250 350 500 750 1000

410 490 590 725 825

445 580 635 780 885

390 470 565 685 770

410 505 605 740 830

250 350 500 750 1000

320 385 465 580 670

350 420 500 625 725

305 370 445 550 635

325 400 480 590 680

1/ 2/ 3/ 4/

Two Circuits, Six Conductors [See Figure 311.60(D)(3), Detail 8.) 8 6 4 2 1/ 2/ 3/ 4/

0 0 0 0

Two Circuits, Six Conductors [See Figure 311.60(D) (3), Detail 8.)

140 180 205

90 115 150 195 220

105 140 175 200

115 150 190 215

235 265 300 340

250 285 320 365

225 255 290 325

240 275 315 350

85

no

250 370 395 355 380 350 445 480 425 455 500 535 575 510 545 750 700 650 615 660 1000 740 795 690 745 Note: Refer to 31 l.60(F) for basis ofampacities and Table 31 l.IO(A) for the temperature rating of the conductor.

2020 Edition

NATIONAL ELECTRICAL CODE

8 6 4 2

65 85 110 140 160

70 95 120 150 170

85 105 135 155

90 ]]5 145 170

1/ 0 2/ 0 3/ 0 4/ 0

180 205 235 265

195 220 250 285

175 200 225 255

190 215 245 275

250 290 310 280 300 350 350 375 335 360 500 420 455 405 435 750 520 560 485 525 1000 600 645 565 605 Note: Refer to 311.60(F) for basis ofampacities and Table 311.IO(A) for the temperamre rating of the conductor.

70-177

ARTICLE 311 -MEDIUM VOLTAGE CONDUCTORS AND CABLE

311.60

-~ in

r::. E E

"

Detail 1 290 mm x 290 mm (11.5 in. x 11.5 in.) Electrical duct bank One electrical duct

0

(j)

190 mm (7.5 in.) Detail 2 475 mm x 475 mm (19 in. x 19 in.) Electrical duct bank Three electrical ducts or

190 mm (7.5 in.) Detail 3 475 mm x 675 mm (19 in. x 27 in.) Electrical duct bank Six electrical ducts or

190 mm 190 mm (7.5 in.) (7.5 in.)

.si in

r::.

675 mm x 290 mm (27 in. x 11.5 in.) Electrical duct bank Three electrical ducts

E

E @

190 mm 190mm (7.5 in.) (7.5 in.) 675 mm x 475 mm (27 in. x 19 in.) Electrical duct bank Six electrical ducts

•

Detail 5 Buried 3 conductor cable

r

600mm (24 in.) Detail 6 Buried 3 conductor cables

190mm 190 mm (7.5 in.) (7.5 in.)

rrl

Detail 9 Buried single-conductor cables (1 circuit)

l

600mm (24 in.)

•••

Detail 8 Buried triplexed cables (2 circuits)

Detail 7 Buried triplexed cables (1 circuit) 190mm 190mm (7.5 in.) (7.5 in.)

rrr

600mm (24 in.)

190 mm 190 mm (7.5 in.) (7.5 in.)

I I l

Detail 10 Buried single-conductor cables (2 circuits) Legend

Note: Minimum burial depths to top electrical ducts or cables shall be in accordance with 300.50. Maximum depth to the top of electrical duct banks shall be 750 mm (30 in.) and maximum depth to the top of direct-buried cables shall be 900 mm (36 in.).

~

Backfill (earth or concrete)

0

Electrical duct

•

Cable or cables

FIG URE 311. 60 (D) (3) Cable Installation Dimensions for Use with Table 311.60 (C) (77) Through Table 311.60(C)(86).

70-178

NATION AL ELECTRICAL CODE

2020 Edition

ARTICLE 312 -

CABINETS, CUTOUT BOXES, AND METER SOQIBT ENCLOSURES

Table 311.60(D)(4) Ambient Temperature Correction Factors For ambient temperatures other than 40°C (104°F), mtdtiply the allowable ampacities specified in the ampacity tables by the appropriate factor shown below. Ambient Temperature (°C)

IO or less 11-15 16-20 21-25 26-30 31-35 36-40 41-45 46-50 51-55 56-60 61-65 66-70 71-75 76-80 81-85 86-90 91-95 96-100

Temperature Rating of Conductor 90°C

105°C

Ambient Temperature (oF)

1.26 1.22 1.18 1.14

1.21 l.18 1.14 1.11 I.07 I.04 1.00 0.96 0.92 0.88 0.83 0.78 0.73 0.68 0.62 0.55 0.48 0.39 0.28

50 or less 51-59 60-68 69-77 78-86 87-95 96-104 105-113 114-122 123-131 132-140 141-149 150-158 159-167 168-176 I 77-185 186-194 195-203 204-212

l.IO

l.05 1.00 0.95 0.89 0.84 0.77 0.71 0.63 0.55 0.45 0.32 -

-

ARTICLE 312 Cabinets, Cutout Boxes, and Meter Socket Enclosures

312.3 Position in Wall. In walls of concrete, tile, or other noncombustible material, cabinets shall be installed so that the front edge of the cabinet is not set back of the finished surface more than 6 mm (Y.1 in.) . In walls constructed of wood or other combustible material, cabinets sha ll be flush wi th the finished surface or project therefrom. 312.4 Repairing Noncombustible Surfaces. Noncombustible surfaces that are broken or inco mplete shall be repaired so there will be no gaps 01- open spaces greater than 3 mm (Ys in.) at the edge of the cabin et o r cutout box emp loying a flush-type cover. 312.5 Cabinets, Cutout Boxes, and Meter Socket Enclosures. Conductors entering en closures within the scope of d1is article shall be protected fro m abrasion and shall comply with 312.5(A) through (C) . (A) Openings to Be Closed. Openings th roug h wh ich conductors enter shall be closed in an approved manner. (B) Metal Cabinets, Cutout Boxes, and Meter Socket Enclosures. \!\There metal e ncl osures wi thin the scope of this article are installed with messenger-supported wiring, open wiring on insulators, or concealed knob-and-tube wit-ing, conductors shall enter through insulating bushings or, in dry locatio ns, through flexible tubing extending from the last insulating support an.cl firmly sectu-ed to the enclosu re. (C) Cables. \!\There cable is used, each cable shall be secured to the cabinet, cutout box, or meter socket enclosure. Exception No. 1: Cables with entirely nonmetallic sheaths shall be permitted to enter the top of a surface-mounted enclosure through one or more nonflexible raceways not less than 450 mm ( 18 in.) and not more than 3. 0 m (JO ft) in length, provided all of the following conditions are met: ( 1) (2) (3)

Part I. Scope and Installation 312.1 Scope. This article covers the installation and construction specifications of cabinets, cutout boxes, and meter socket enclosmes. It does not apply to equipment operating at over 1000 volts, except as specifically referenced elsewh ere in the Code. 312.2 Damp and Wet Locations. In damp or wet locations, surface-type enclosures within the scope of this article shall be placed or equipped so as to pi-event moisture or water from entering and accumulating with in the cabinet or cutout box, and shal l be motmted so there is at least 6-mm (\tion No. 1: Cables passing from an enclosure or room that is unclassified as a result of Type Z pressurization into a Zane 2 location shall not require a seal at the boimdmy. Exception No. 2: Shielded cables and twisted pair cables shall not require the removal of the shielding material or separation of the twisted pairs, provided the termination is by an approved means to minimize the entrance of gases or vapors and prevent propagation of flame into the cable core.

(b) Cables That Will Not Transmit Gases or Vapors. Cables with a gas/ vaportight continuous sheath and that will not transmit gases or vapors through the cable core in excess of the quantity permitted for seal fittings shall not be required to be

2020 Edition

NATIONAL ELECTRICAL CODE

Informational Note No. I : For further information on construction, testing, and marking of cables, cable fittings, and cord connectors, see ANSI/ UL 222.5-2013, Cabks and Cable-Fittings for

Use in HazardotLS (Classified) Locations.

(c) Cables Capable of Transmitting Gases or Vapors. Cables with a gas/vaportight continuous sheath capable of u·ansmitting gases or vapors through the cable core shall not be requi1-ed to be sealed except as required in 505.16(C)(2)(b), unless the cable is attached to process equipment or devices that may cause a pressure in excess of 1500 pascals (6 in. of water) to be exerted at a cable end, in wh ich case a seal, barrier, or other means sha ll be provided to prevent migration of flammables into an unclassified area. Exception: Cables with an unbroken gas/vapartight contimurns sheath shall be permitted to pass through a Zone 2 location without seals. (d) Cables Without Gas/Vapartight Continuous Sheath. Cables that do not have gas/ vaportight continuous sheath shall be sealed at the boundary of the Zone 2 and unclassified location in such a manner as to m inimize the passage of gases or vapors into an unclassified location. Informational Note: The cable sheath may be either metal or a nonmetallic material.

(D) Zones O, I , and 2. Where required, seals in Zones 0, 1, and 2 locations shall comply with 505.16(D) (l) through (D) (5) . (I) Fittings. Enclosures for connections or equipment shall be provided with an integral means for sealing, or sealing fittings listed for the location sha ll be used. Sealing fittin gs shal l be listed for use with one 01· mme specific compounds and shall be accessible . (2) Compound. The compound shall provide a seal against

passage of gas 01· vapors through the seal fitting, sha ll not be affected by the surroun ding atmosphere or liquids, and shall not have a melting point less than 93°C (200°F) . (3) Thickness of Compounds. In a completed seal, the mini-

mum thickness of the sealing compound shall not be less than the u·ade size of the sealing fitting and, in no case, less than 16 mm (o/s in.) . Exception: Listed cable sealing fittings shall not be required to have a minimum thickness equal to the trade size ofthe fitting.

(4) Splices and Taps. Splices and taps shall not be made in fittings intended only for sealing with compound, nor shall other fittings in which splices or taps are made be filled with compound. (5) Conductor or Optical Fiber Fill. The cross-sectio nal area of the conductors or optical fiber tubes (metallic or nonmetallic) permitted in a seal shall not exceed 25 percent of the crosssectiona l area of a rigid metal conduit of the same trade size unless it is specifically listed fo1- a h igher percentage of fill.

70-399

505.16

ARTICLE 505-ZONE 0, 1, AND 2 LOCATIONS

(E) Drainage. (1) Control Equipment. Where there is a probabil.ity that

liquid or other condensed vapor may be u-apped within enclosures for control equipment or at any point in the raceway system, approved means shal l be provided to prevent accumulation or to permit periodic draining of su ch liquid or condensed vapor. (2) Motors and Generators. V\'here liquid or condensed vapor

may accumulate within motors or generators, j oints and conduit systems shall be arranged to minimize entrance of liquid. If means to prevent accumulation or to permit periodic draining are necessary, such means shall be provided at the time of manufacnire and shall be considered an integral part of the machine. 505.17 Flexible Cables, Cords and Connections. (A) Flexible Cords, Zones 1 and 2. A flexible cord shall be

permitted for connection between portable lighting equipment or other portable utilization equipment and the fixed portion of their supply circuit. Flexible cord shall also be permitted for that portion of the circuit where the fixed wiring methods of 505.1 5(B) and (C) cannot provide the necessary degree of movement for fixed and mobile electrical utilization equipment in an industrial establishment where conditions of maintenance and engineering supervision ensure that only qualified persons install and service the installation, and where the flexible cord is protected by location 01- by a suitable gua1-d from damage. The length of the flexible cord shall be continuous. '"'here flexible cords are used, the cords shall comply with the following: (l) (2) (3) (4)

(5)

(6)

Be of a type listed for extra-hard usage . Contain, in addition to the conductors of the circuit, an equipment grounding conductor complying with 400.23. Be connected to terminals or to supply conductors in an approved manner. Be supported by clamps or by other suitable means in such a manner that there will be no tension on the terminal connections. Be terminated with a listed cord connector that maintains the type of protection where the flexible cord enters boxes, fittings, or enclostll'es that are requi1-ed to be explosionproof or flameproof. Cord entering an increased safety "e" enclosure shall be terminated with a listed increased safety "e" coi-d connector. Informational Note: See 400.10 for permitted uses of flexible cords.

Elecu-ic submersible pumps with means for removal without entering the wet-pit shall be considered portable utilization equipment. The extension of the flexible cord within a suitable raceway between the wet-pit and the power source shall be permitted. Elecu-ic mixers intended for travel into and out of open-type mixing tanks or vat5 shall be considered portable utilization equipment. Informational Note: See 505.18 for flexible cords exposed to liquids having a deleterious effect on the conductor insulation.

70-400

(B) Instrumentation Connections for Zone 2. To facilitate replacements, process conu-ol insu-uments shall be permitted to be connected through flex ible cords, attachmen t plugs, and receptacles, provided that all of the fo llowing conditions apply:

(1)

(2) (3)

(4) (5)

A switch listed for Zone 2 is provided so that the attachment plug is not depended on to interrupt current, unless the c ircuit is type "ia," "ib," or "ic" protection, in which case the switch is not required. The current does not exceed 3 amperes at 120 volts, nominal. The power-supply cord does not exceed 900 mm (3 ft), is of a type listed for extra-hard usage or for hard usage if protected by locati on, and is supplied through an attachment plug and receptacle of the locking and grounding type. Only necessary receptacles are provided. The receptacle carries a label warning against unplugging under load.

505.18 Conductors and Conductor Insulation. (A) Conductors. For type of protection "e," fie ld wmng

conductors shall be copper. Every conductor (including spares) that enters Type "e" equipment shall be terminated at a Type "e" terminal. (B) Conductor Insulation. Where condensed vapors or liquids

may collect on, or come in contact with, the insulation on conductors, such insulation shall be of a type identified for use under su ch conditions, or the insulation shall be protected by a sheath of lead or b y other approved means. 505.19 Uninsulated Exposed Parts. There shall be no uninsulated exposed parts, such as elecu-ical conductors, buses, terminals, or components, that operate at mo1-e than 30 volts (15 volts in wet locations) . These parts shall additionally be protected by type of protection "ia", "ib", or "ic" that is suitable fo1- the location. 505.20 Equipment Requirements. (A) Zone 0. In Zone 0 locations, only equipment specifi cally

listed and marked as suitable for the location shal l be permitted. Exception: Intrinsicall:y safe apparatus listed for use in Class I, Division 1 locations for the same gas, or as permitted by 505. 9(B)(2), and with a suitable temperature class shall be permitted.

(B) Zone I. In Zone l locations, only equipment specifi cally listed and marked as suitable for the location shall be permitted. Exception No. 1: l,quipment identified f leum Gas Code. Informational Nore No. 2: For information on classified areas pertain ing ro LP-Gas systems other than residential or commercial, see NFPA 58-2017, Liqiwfied Petroleum Gas Code, and NFPA 59-2018, Utility LP-Gas Plant Code. Informational Note No. 3: See 514.3(C) for motor fuel dispensing stations in marinas and boatyards.

2020 Edition

NATIONAL ELECTRICAL CODE

70-415

514.3

ARTICLE 514-MOTOR FUEL DISPENSING FACILITIES

Table 514.3(B)(l ) Class I Locations Location

Motor Fuel Dispensing Facilities

Division (Group D)

Zone (Group IIA)

Dispensing Device (except Overhead Type) 2• 3 Under d ispenser containment Dispenser

2

2

O utdoor

2

2

Indoor - with mechanical ventilation

2

2

- \\~ th gravity ventilation

2

2

Dispensing Device - Overhead Type 4

2

2

2

2

Remote Pump O utdoor

2

2

2

2

Indoor

Sales, Storage, Rest Rooms i ncluding structures (such as the attendant's kiosk) on or adjacent to d ispensers

l

l

2

2

2

2

unclassified l

unclassified 1

2

2

Tank, Aboveground Inside tank Shell, ends, roof; d ike area

Vent

0 l

2

2

2

2 1

2

2

Extent of Classified Location1

Entire space within and und er d ispenser p it o r containment Within 450 mm (18 in .) of d ispenser enclosure or that portion of dispenser enclosure contain ing liquidhandling componentS, extending horizontally in all d irections and down to grade level Up to 450 mm (18 in .) above grade level, extending 6 m (20 ft) horizontally in all d irections from d is penser enclosu re Up to 450 mm (18 in .) above floo r level, extending 6 m (20 fr) ho1i zontaUy in a ll d irections from d ispenser enclosu re Up to 450 mm (18 in .) above floor level, extending 7.5 m (25 ft) horizontally in a ll d irections from dispenser enclosu re Space with in d ispenser enclosure and all electrical equipmen t integral with dispensing hose or nozzle Within 450 mm (18 in .) of d ispenser enclosure, extending horizontally in all d irections and down to grade level Up to 450 mm (18 in .) above grade level, extending 6 m (20 ft) ho1izontally in all d irections from a poin t vertically below edge of d ispenser enclosu re En tire space within any pit or box below grade level, any part of which is \\~ th i n 3 m (10 ft) horizontally from any edge of pump Within 900 mm (3 f t) of any edge of pump, extending horizontally in all directions Up to 450 mm (18 in .) above grade level, extending 3 m (l 0 ft) horizontally in a ll d irections from any edge of pump Entire space within any pit Within 1.5 m (5 ft) of any edge of pump, extending in all di rections Up to 900 mm (3 f t) above floor level, extending 7.5 m (25 ft) ho1izontally in a ll d irections from any edge of pump Except as noted be low Entire volume, if there is any open ing to room extent of a Division l or Zone l location E n tire volume, if there is any opening to room exte n t of a Division 2 or Zone 2 location

\\~thi n

the

'~ th i n

the

En tire inside volume En tire space within d ike, where d ike he ight exceeds d istance from tank shell to inside of d ike wall for more d1an 50 p ercent of tank circumference Entire space wi thin d ike, where d ike he ight does not exceed d istance from tank shell to inside of d ike wall for more d1an 50 pe rce n t of tank circumfere nce Within 3 m (10 ft) of shell, ends, or roof of tank Within l .5 m (5 ft) of open end of vent, extending in a ll directions Be tween 1.5 m and 3 m (5 ft and 10 ft) from open end of vent, exte nding in a ll d irections (continues)

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NATIONAL ELECTRICAL CODE

2020 Edi tion

ARTICLE 514-MOTOR FUEL DISPENSING FACILITIES Table 5 14.3(B)( l )

5 14.3

Continued

Location

Division (Group D)

Zon e (Group IIA)

Extent o f Classified Location1

1

0

2

2

2

2

Entire inside volume Entire space within any p it or box below grade level, any part of which is within a Division 1 or Division 2 classified location or within a Zone l or Zone 2 classified location Up to 450 mm (18 in.) above grade level, extending 1.5 m (5 ft) hoiizontally in all d irections from any tight-fill connection and extending 3 m (l 0 ft) ho1izontally in a ll d irections from any loose-fill connection Within 1.5 m (5 f t) of open end of vent, extend ing in all d irections Be tween 1.5 m and 3 m (5 ft and 10 ft) from open end of vent, extending in all directions

Tank, Underground !J1side tank Fill Ope ning

Vent

Vap or Processing System Pits

1

Equipme nt in protective enclosures Equipment not within protective enclosure

2

2

2

2

2

2

2

2

2

2

2

2

- Equipme nt enclosure

- Vacuum assist blower

Vault

Entire space within any p it or box below grade level, any part of which : (l) is with in a Division l or Division 2 classified location; (2) is \\1thin a Zone 1 or Zone 2 classified location; (3) houses any equipmen t used to transfer or process vapors Entire space within enclosure Within 450 mm (18 in .) of equipment contain ing flammable vapors or liquid, extending horizontally in all d irections and down to grade level Up to 450 mm (18 in.) above grade level within 3 m (10 fi:) horizontally of the vapor processing equipment Entire space within enclosure, if flammab le vapor or liquid is present under normal operating conditions Entire space \\~thin enclosure , if flammable vapor or liquid is not present under normal operating conditions Within 450 mm (18 in .) of blower, extending horizontally in all d irections and down to grade level Up to 450 mm (18 in.) above grade level, extending 3 m (10 ft) horizontally in a ll d irections Entire interior space, if Class I liquids are stored \\1th in

1

For marine applicalio n, grade IRvel means the surface of a pier, extending down to water level. 2 Refrr to Figure 514.3 a nd Figure 514.3(B) for an illustration of classified location around dispensing devices. 3 Area classification inside the dispenser enclosure is covered in UL 87, Standard for Powe1cOjJemled Dispensing Devices/or PelroleurnProduclS. 'Ceiling-mounted hose reel. [30A:Table 8.3.l]

Table 514.3(B)(2) Electrical Equip m en t O assified Areas for D ispensing D evices Extent of Classified Area Dispensing Device

Class I, Division l

Compressed natural gas (CNG)

Entire space within the dispenser enclosure

Liquefied natural gas (LNG)

Entire space within the dispenser enclosure

Lique fied petroleum gas (LP-Gas)

Entire space within the dispenser enclosure; 450 mm (18 in.) from the exterior su rface of the d ispenser enclosure to an elevation of 1.22 m (4 ft) above the base of the dispenser; the entire p it or open space beneath the d ispenser and within 6 m (20 ft) horizontally from any edge of the dispenser when the pit or trench is not mechanically ventilated

Class I, Division 2 1.5 m (5 ft) in all d irections from dispenser

enclosure 3 m (10 ft) in all d irections from the dispenser enclosure Up to 450 m m (18 in.) above ground and \\1thin 6 m (20 ft) hoiizontall)' from any edge of th e d ispenser enclosure, including pits or trenches within this area when pro\1ded \\1th adequate mechanical ventilation

[30A:Table 12.6.2]

2020 Edition

NATIONAL ELECTRICAL CODE

70-417

514.3

ARTICLE 514-MOTOR FUEL DISPENSING FACILITIES

(3) Fuel Storage. (a) Aboveground tanks storing CNG or LNG shall be separated from any adjacent property line that is or can be built upon, any public way, and the nearest important building on the same property. [30A:l2.3.l ]

(C) Motor Fuel Dispensing Stations in Boatyards and Marinas.

lnformational Note: The relevant distances are given in Section 8.4 of NFPA 52-2019, Vehicular Natural Gas Fuel S)•stems Code.

(l) General. Electrical wiring and equipment located at 01serving motor fuel dispensing locations shall be installed on the side of the wharf, pier, or dock opposite from the liquid piping system.

(b) Aboveground tanks storing hydrogen shall be separated from any adjacent property line that is or can be built upon, any public way, and the nearest important building on the same property. (30A:l2.3.2] Informational Note: The relevant NFPA 2-2016, H)•drogen Technologies Code.

distances

given

in

(c) Aboveground tanks storing LP-Gas shall be separated from any adjacent property line that is or can be built upon, any public way, and the nearest important building on the same property. [30A:l2.3.3] Informational Note: The relevant distances are given in Section 6.3 of NFPA 58-2017, Liquefied Petro/,eum Gas Code.

(d) Aboveground tanks storing CNG, LNG, or LP-Gas shall be separated from each other by at least 6 m (20 ft) and from dispensing devices that dispense liquid or gaseous motor vehicle fuels by at least 6 m (20 ft) . [30A:l2.3.3l

lnfo1·mational Note: For additional information, see NFPA 303-2016, Fire Protection Standard for Marinas and Boatyards, and NFPA 30A-2018, Code for Motor Fuel Disf1ensing Facilities and Re/Jair Garages.

(2) Classification of Class I , Division I and 2 Areas. The following criteria shall be used for the purposes of applying Table 514.3(B)(l) and Table 514.3(B)(2) to motor fue l dispensing equipment on floating or fixed piers, wharfs, or docks. (D) Closed Construction. Whe1-e the consu·uction of floating docks, piers, or wharfs is closed so that there is no space between the bottom of the dock, pier, or wharf and the water, as in the case of concrete-enclosed expanded foam or similar consu·uction, and the construction includes integral service boxes with supply chases, the following shall apply: (1)

(2)

E-.:ception No. 1: The required separation shall not apply to tanks or dispensers storing or handling fuels of the same chemical composition. Exception No. 2: The required separation shall not apply when both the gaseous fuel starage and dispensing equipment are at least 15 m (50 ft) from any other aboveground motor fuel starage or dispensing equipment. lnformational Note: For further information, see NFPA 52-2019, Vehicular Natural Gas Fuel S)•Slems Code, or NFPA 58--2017, Liquefied Petroleum Gas Code, as applicable.

(e) Dispenser Installations Beneath Canapies. Where CNG or LNG dispensers are installed beneath a canopy or enclosure, e ither the canopy 01- enclosure shall be designed to prevent accumulation or entrapment of ignitible vapors or all electrical equipment installed beneath the canopy or enclosure shall be suitable for Class I, Division 2 hazardous (classified) locations. (30A:l2.4l (f) Specific Requirements fm· LP-Gas Dispensing DeviCPs . [30A:l2.5l Dispensing devices for LP-Gas shall b e located a5 follows: (1) (2)

At least 3 m (10 ft) from any dispensing device for Class I liquids At least 1.5 m (5 ft) from any dispensing device for Class I liquids where the following conditions exist: a. The LP-Gas deliver nozzle more than 4 cm 3 (0.1 oz) tion . b. The fixed maximum liquid during the entire refoeling

Exception No. 2: Dock, piei; ar whmf sections that do not support fuel dispensers and do not di1l!ctly abut sections that suppart fuel dispensers shall be permitted to be unclassified whem documented air space is provided and where flammable liquids or vapors cannot travel to such dock sections. The documentation shall comf1ly with 500.4. (E) Open Construction. Where the construction of piers, wharfs, or docks is open, as in the case of decks bui lt on stringers supported by pilings, floats, pontoons, or similar consu·uction, the following shall apply:

(1)

(2)

Table 5 14.3(B) (2) shall be used to delineate and classify areas for the purpose of installation of electrical wiring and electrical utilization equipment.

70-418

Exception No. 1: Dock, piei; or whmf sections that do not support fuel dispensers and abut, but ml! located 6.0 m (20 ft) or marn from, dock sections that support a fuel dispen5er(s) shall be permitted to be Class I, Division 2 locations whei·e documented air space is provided between dock sections to allow flammable liquids ar vapors to dissipate withmit traveling to such dock sections. The documentation shall comply with 500.4.

and filler valve release no of liquid upon disconneclevel gauge remains closed process. [30A:l2.5.2]

The space above the surface of the floating dock, pier, or wharf shall be a Class I, Division 2 location with distances as specified in Table 514.3(B)(l ) for dispenser and ou tdoor locations. Spaces below the surface of the floating dock, pier, or wharf that have areas or e nclosures, su ch as tubs, voids, pits, vaults, boxes, depressions, fuel piping cha5es, or sim ilar spaces, where flammable liquid or vapor can accumulate shall be a Class I , Division 1 location .

The area 450 mm (18 in.) above the surface of the dock, pie1~ or wharf and extending 6.0 m (20 ft) h orizontally in all d irections from the outside edge of the dispenser and down to the water level s hall be a Class 1, Divis ion 2 location. Enclosures such as tubs, voids, pits, vaults, boxes, depressions, piping chases, or similar spaces where flammable liquids or vapors can accwmtlate within 6.0 m (20 ft) of the dispenser shall be a Class I, Division 1 location .

NATIONAL ELECTRICAL CODE

2020 Edition

ARTICLE 514 - MOTOR FUEL DISPENSING FACILITIES 514.4 Wiring and Equipment Installed in Class I Locations. All e lecu·ical equipment and wiring installed in Class I locations as classified in 514.3 shall comply with the applicable provisions of Article 5 01. Exception: As permitted in 514.8. Informational Note: For special requirements for conductor insulation, see 501.20.

514.7 Wiring and Equipment Above Class I Locations. Wiring and equipment above the Cla5s I locations as classified in 514.3 shall comply with 5 11.7. 514.8 Underground Wiring. Undergrotmd wiring shall be installed in threaded rigid metal conduit or threaded steel intermediate metal conduit. Any portion of elecu·ical wit-ing that is below the surface of a Class I, Division 1 or a Class I, classified in Ta ble 514.3( B)(l) and Division 2 location Table 514.3( B) (2) l shall be sealed within 3.05 m (10 ft) of the point of emergence a bove grade . Except for listed explosionproof reducers at the conduit seal, there shall be no union , coupling, box, or fitting between the conduit seal and the point of emergence above grade. Refer to Table 300.5.

ras

.Exception No. 1: Type MI cable shall be permitted where it is installed in accordance with Article 332. Exception No. 2: Type PVC conduit, Type RTRC conduit, and Type HDPE conduit shall be permitted where buried under not less than 600 mm (2 ft) of cover. Whei~ Type PVC conduit, 1)pe RTRC conduit, or Type HDPE conduit is used, threaded rigi,d metal conduit or threaded steel intmnediate metal conduit shall be used for the last 600 mm (2 ft) of the underground run to emergence or to the point of connection to the aboveground raceway, and an equipment grounding conductor shall be included to provide electrical continuity of the raceway system and for grounding of non-current-carrying metal parts.

514.9 Sealing. (A) At Dispenser. A listed seal shall be provided in each conduit run entering or leaving a dispenser or any cavities or enclosw·es in direct com munication therewith. The sealing fitting or listed explosionproof reducer at the seal shall b e the first fitting after the conduit emerges from the earth or concrete . (B) At Boundary. Additional seals shall be provided in accordance with 501.1 5. Sections 501.1 5(A) ( 4) and (B) (2) sh a ll apply to horizontal as well as to vertical bo undaries of the defined Class I locations.

2020 Edition

NATIONAL ELECTRICAL CODE

514.16

514.11 Circuit Disconnects. (A) Emergency Electrical Disconnects. Fuel dispensing systems shall be provided with one or more clearly identifi ed emergency shutoff devices or e lectrical disconnects. Suc h devices or discoimects shall be installed in a pproved locations but not less than 6 m (20 ft) or more than 30 m (100 ft) from the fue l dispensing devices that they serve. Emergency shutoff devices 01· electrical d isconnects sha ll disconnect power to a ll dispensing devices; to a ll remote pumps serving the dispensing devices; to a ll associated power, conu·ol, and sig nal circuits; and to all other elecu·ical equipmen t in the haza1·dous (classified) locations surrounding the fuel dispensing devices. v\Then more than one emergency shutoff device or e lectrical disconnect is provided, a ll devices shall be interconnected. Resetting from an emergency shutoff condition shall require ma nual i ntervention and the manner of resetting shall be approved by the a uthority having jurisdiction . [30A:6.7] The e mergency shutoff device shall disconnect simultaneously from the source of supply, a ll conductors of the circuits, including the grounded conductor, if any. Equipment grounding conductors sha ll remain connected. Exception: Intrinsical!J safe electrical equipment need not meet this requii~ment. [30A:6. 7] (B) Attended Self-Service Motor Fuel Dispensing Facilities. At attended motor fuel dispensing faci lities, the devices or disconn ects shall be readily accessible to the attendant. [30A:6 .7. l J (C) Unattended Self-Service Motor Fuel Dispensing Facilities. At unattended moto r fuel dispensing facilities, th e devices o r disconnects sh a ll be readily accessible to pau·ons and at least one additional device or disconnect shall be readily accessible to each group of dispensing devices on a n individual island. [30A:6.7.21

514.13 Provisions for Maintenance and Service of Dispensing Equipment. Each dispensing device shall be provided with a means to remove all external voltage sources, including power, com municati ons, data, a nd video circuits and including feedback., during p eriods of maintenance and service of the dispensing equipment. The location of this means shall be permitted to be other than inside or adjacent to the dispensi ng device. The means shall be capable of being locked in the open position in accordance wid1 110.25. 514.16 Grounding and Bonding. All metal raceways, th e metal armor or metallic sh eath on cables, and a ll non-currentcarrying metal parts of fixed and portable elecu·ical equipme n t, regardless of voltage, shall be grounded and b onded. Grounding and b onding in Class I locatio ns shall comply with 501.30.

70-419

515.1

ARTICLE 515-BULKSTORAGE PLANTS

ARTICLE 515 Bulk Storage Plants 515.1 Scope. This article covers a property or portion of a property where flammable liquids are received by tank vessel, pipelines, tank car, or tank vehicle and are stored 01· blended in bulk for the purpose of disu-ibuting such liquids by tank vessel, pipeline, tank car, tank vehicle, portable tank, or container. Informational Nole: Texl llrnt is followed by a reference in brackels has been extraCled from NFPA 30-2018, 1'1armnabf£ and CornbtlSlible Liquids Code. Only ediwrial changes were made lO lhe ex[raCled lext LO make il consislem wilh lhis Code.

515.3 Classified Locations. v\lhere the term "Class I" is used \'lith respect to Zone classifications within this article of the Code, it shall apply to Zone 0, Zone 1, and Zone 2 designations. Informational Note: The term "Class I" was originally included as a prefix lo Zone 0, Zone 1, and Zone 2 locations and references as an identifier for flammable gases, vapors, or liquids lo differentiale from Class ll and Class Ill locations. Zone 0, Zone l, and Zone 2 on ly apply lO flammable gases, vapors, or liquids so lhe "Class I" prefix is red undam and has been deleled, except for text that is extracted from other documents or to remain consislem throughoul this article.

Table 515.3 shall be applied whe1·e Class I flammable liquids are stored, handled, or dispensed and shall be used to delineate and classify bulk storage plants. The classified location shall not extend beyond a floor, wall, roof~ or other solid partition that has no communicating openings. Informational Nole No. l: The area classifications !isled in Table 515.3 are based on the premise that the inst:allation meets the applicable requirements of NFPA 30-2018, Flarnrnable and Corn/rnslible Liquids Code, Chapter 5, in all respects. Should this not be the case, lhe aurhorily having jurisdiction has lhe amhority to classify the extent of d1e class.ified space. Informational Nole No. 2: See .514.3(C) lhrough (E) for gasoline dispensing stations in marinas and boatyards.

5 15.4 Wiring and Equipment Located in Class I Locations. All electrical wi1·ing and equipment \'lithin the Class I locations defined in 515.3 shall comply with the applicable provisions of Article 501 or Article 505 for the division or zone in which they are used. Exception: As permitted in 515.8.

5 15. 7 Wiring and Equipment Above Class I Locations. (A) Fixed Wiring. AIJ fixed wiring above Class I locations shall be in metal raceways, Schedule 80 PVC conduit, Type RTRC marked with the suffix -Xv\/, or Type MI, Type TC, or Type MC cable, or Type PLTC and Type PLTC-ER cable in accordance with the provisions of Article 725, including installation in cable tray systems or Type ITC and Type ITC-ER cable as permitted in 727.4. The cable shall be te1·minated with listed fittings.

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(B) Fixed Equipment. Fixed equipment that may produce arcs, sparks, or particles of hot metal, such as lamps and lampholders for fixed lighting, cutouts, switches, receptacles, motors, or other equipment having make-and-break or sliding contacts, shall be of the totally enclosed type or be constructed so as to prevent the escape of sparks or hot metal particles.

(C) Portable Luminaires or Other Utilization Equipment. Po1·table luminaires or other utilization equipment and their flexible cords shall comply with the provisions of Article 501 or Article 505 for the cla5s of location above which they are connected 01· used.

515.8 Underground Wiring. (A) Wiring Method. Underground \vi ring shall be installed in tlu·eaded rigid metal conduit or threaded steel intermediate metal conduit or, where buried under not less than 600 mm (2 ft) of cover, shall be permitted in Type PVC conduit, Type RTRC conduit, or a listed cable. Where Type PVC conduit or Type RTRC conduit is used, threaded rigid metal conduit or threaded steel intermediate metal conduit shall be used for not less than the last 600 mm (2 ft) of the conduit run to the conduit point of emergence from the underground location or to the point of connection to an aboveground raceway. Where cable is used, it shall be enclosed in threaded rigid metal conduit or threaded steel intermediate metal conduit from the point of lowest buried cable level to the point of connection to the abovegr0tmd raceway. (B) Insulation. Conductor insulation shall comply with 501 .20 . (C) Nonmetallic Wiring. v\lhere Type PVC conduit, Type RTRC conduit, or cable with a n onmetallic sheath is used, an equipment grounding conductor shall be included to provide for elecu-ical continuity of the raceway system and for grounding of non-current-carrying metal parts.

5 15.9 Sealing. Sealing requirements shall apply to horizon tal as well as to vertical boundaries of the defined Class I locations. Buried raceways and cables under defined Class I locations shall be considered to be within a Class I, Division 1 or Zone 1 location. 515.10 Special Equipment - Gasoline Dispensers. v\lhere gasoline or other volatile flammable liquids or liquefied flammable gases are dispensed at bulk stations, the applicable provisions of Article 514 shall apply. 515.16 Grounding and Bonding. All metal raceways, the metal armor or metallic sheath on cables, and all non-currentcarrying metal parts of fixed or portable e lectrical equipment, regardless of voltage, shall be grounded and bonded. Grounding and bonding in Class I locations shall comply with 501.30 for Class I, Division I and 2 locations and 505.25 for Zone 0, 1, and 2 locations. Informational Nole: For information on grounding for static protection, see 6.5.4 of NFPA 30-2018, flammable and Combustible Liquids Code.

NATIONAL ELECTRICAL CODE

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ARTICLE 515-BULKSTORAGE PLANTS

515.16

Table 515.3 Electrical Area Classifications Location

Division

Indoor equipment installed where flammab le vapor-air mixtures can exist under normal operation (see I nformational Note)

2

Outdoor equipment installed where flammab le vapor-air mix tures can exist under nonnal operation

2

Tank storage installations inside b uild ings

Zone

Extent of Classified Are a

0

The entire area associated with such equipment where flammable gases or vapors are present continuously or for long periods of time

2

0

The e ntire area associated with such equipment where flammable gases or vapors are present continuously or for long pe1i ods of ti me

l

Arca within 900 mm (3 f t) of any edge of such equipment, exte nding in all directions Area between 900 mm (3 ft) and 2.5 m (8 ft) of any edge of such equipment, extending in all d irections; also, space up to 900 mm (3 ft) above floor or grade level within 900 mm to 3.0 m (3 ft to IO ft) horizontally from any edge of such equipment

2

I

2

2 0 1

Tank - abovegrou nd, fixed roof

2

2 0 I

2 Tank - abovegrou nd, floating roof With fixed outer roof With no fixed outer roof

Area within 1.5 m (5 ft) of any edge of such equipment, extending in all d irections Area between 1.5 m and 2.5 m (5 ft and 8 ft) of any edge of such equipment, extending in all directions; also, space up to 900 mm (3 ft) above floor or grade level within I .5 m to 7.5 m (5 fi: to 25 ft) horizontally from any edge of such equipment'

2

0 l

All equipment located below grade level Any equipment located at or above grade level Inside fixed roof tank Area inside d ike where d ike height is greater than the d istance from the tank to the d ike for more than 50 percen t of the tank circumference With in 3.0 m (IO ft) from shell, ends, or roof of tank; also, area inside d ike to level of top of dike wall Area inside of vent piping or opening With in 1.5 m (5 f t) of open end of vent, extending in all d irections Area between 1.5 m and 3.0 m (5 f t and l 0 f t) from open end of vent, extending in all d irections Area between the floatin g and fixed roof sections and with in the shell Area above the floating roof and within the shell

Tank vault - interior

Entire interior volume, if Class I liq uids arc stored within

Undergrou nd tank fi ll opening

Any pit, box, or space below grade level, if any part is within a Division 1 or 2, or Zone 1 or 2 classified location Up to 450 mm ( 18 in.) above grade level within a horizontal radius of 3.0 m (10 f t) from a loose fi ll connection, and \1~ th i n a horizontal radius of l .5 m (5 ft) from a tight fi ll connection

Vent - d ischarging upward

Drum and container fi lling indoors

2

2

]

0

]

1

2

2

outdoors or

Pumps, bleeders, withdrawal fittings Indoor

Area inside of vent piping or opening 'With in 900 mm (3 fr) of open end of vent, extending in all d irections Area between 900 mm and 1.5 m (3 ft and 5 ft) of open end of vent, extending in all d irections

0

Area inside the drum or container

l

With in 900 mm (3 ft) ofvent and fill openings, extending in all directions Area between 900 mm and 1.5 m (3 ft and 5 ft) from vent or fill opening, extending in all d irections; also, up tO 450 mm (18 in.) above floor or grade level \~thin a horizontal radius of 3.0 m (10 ft) from vent or fiJl opening

2

2

2

2

Within 1.5 m (5 ft) of any edge of such d evices, extending in all directions; also, up to 900 mm (3 ft) above floor or grade level within 7.5 m (25 ft) horizontally from any edge of such de1~ces (continues)

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ARTICLE 515-BULKSTORAGE PLANTS

515.16 Table 515.3

Continued Location

O utdoor

Division

Zone

2

2

Within 900 mm (3 ft) of any edge of such de,~ccs, extending in all directions. Also, up to 450 mm (18 in.) above grade level within 3.0 m (10 ft) horizontally fro m any edge of such devices

1

Entire area with in a pit or sump if any part is within a Division 1 or 2 or Zone l or 2 classified location Entire area within a pit or sump if any part is within a Division 1 or 2 or Zone l or 2 classified location Entire pit or sump

Pits and sumps Without mechan ical ventilation

Extent of Classified Area

With adequate mechan ical ventilation

2

2

Containing valves, fittings, or piping, and not with in a Dh~si on l or 2 or Zone l or 2 classified location

2

2

2

2

Area up to 450 mm (18 in.) above ditch, separator, or ba~i n; also, area up to 450 mm (18 in.) above grade \\~ th i n 4.5 m (15 ft) horizontally from any edge Same a~ pits and sumps

1

0 1

2

2

Area inside of the tank With in 900 mm (3 ft) of edge of dome, exte nding in a ll d irections Area between 900 mm and 4.5 m (3 ft and l 5 ft) from edge of dome, extending in all d irections

l

0

2

2

l

1

2

2

Area between 900 mm and 4.5 m (3 ft and 15 ft) from open end of vent, extending in all d irections; also, within 900 mm (3 ft) of edge of dome, extending in all d irections

Loading through closed dome \\~th vapor control

2

2

Bottom loading with vapor control or any bottom un loading

2

2

With in 900 mm (3 ft) of point of connection of both fi ll and vapor lines extending in all d irections Within 900 mm (3 fr) of point of connections, extending in all directions; also up to 450 mm ( 18 in.) above grade within a horizontal radius of 3.0 m (10 ft) from p oint of connections

Storage and repair garage for tan k vehicles

l

]

2

2

Drainage ditches, separators, impo u nding basins Outdoor

Indoor Tank vehicle and tank car2 Loading through open dome

Loading through bottom connections \\~ th atmosphe1i c ven ting

Loading through closed dome \~ th a tmosphe ric venti ng

Garages for other than tank vehicles

Unclassified

O utdoor drum storage

Unclassified

Inside rooms or storage lockers used for the storage of Class I liquids

2

2

Area inside of the tank Within 900 mm (3 fr) of point of venting to atmosphere, extending in all d irections Arca between 900 mm and 4.5 m (3 ft and 15 ft) from point of venting to atmosphere, extending in all directions; also, up to 450 mm (18 in.) above grade with in a horizontal radius of3.0 m (10 ft) from point of loading connection Withi n 900 mm (3 ft) of open end of vent, extending in all d irections

All pits or spaces below floor level Arca up to 450 mm (18 in .) above floor or grade level for en tire storage or repair garage If there is any opening to these rooms within the extent of an outdoor classified location, the enti re room shall. be classified the same as the area classification at the point of the opening.

E n tire room or locker (continues)

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516.1

ARTICLE 516-SPRAY APPLICATION, DIPPING, COATING, AND PRINTING PROCESSES Table 515.3

Continued Location

Division

Extent of Classified Area

Zone

Indoor warehousing where there is no flammable liquid transfer

Unclas.sified

Office and rest rooms

Unclassified

If there is any opening to these rooms within the extent of an indoor

classified location, the classified location shall extend through the opening to the same exten t as if the wall, curb, o r partition d id not exist. If there is any opening to these rooms within the exten t of an indoor

classified location, the room shall be classified the same as if the wall, curb, or partition did not exist. See Figure 515.3.

Piers and wharves 1

The release of Class I liquids can genernte vapors to the extem that the entire building, and possibly an area surrounding it, should be considered a Class I, Division 2 or Zone 2 location. 2 When classifying extent of area, consideration shall be given to the fact that tank cars or tank vehicles can be spotted at varying points. Therefore, d1e extremities of the loading or unloading positions shal l be used. [30:Table 7.3.3] Informational Note: See Section 7.3 of NFPA 30-2018, Fla111111able and Combustibil: Liquids Code, for additional information.

50 ft

-----..j

j+-2s ft ~

r---soft ft _, r-25

T

25 ft

_l_ Open sump in deck for draining lines and hose

Key:

D

!+--soft I

2ft

FIGURE 515.3

Division 1

~ Division 2

D

Nonclassified

Notes: (1) For SI units, 1 in.= 25 mm: 1 ft = 0.3 m. (2) The ' source of vapor' is the operating envelope and stored position of the outboard flange connection of the loading arm (or hose). (3) The berth area adjacent to tanker and barge cargo tanks is to be Division 2 to the following extent: (a) 25 ft (7.6 m) horizontally in all directions on the pier side from the portion of the hull containing cargo tanks. (b) From the water level to 25 ft (7.6 m) above the cargo tanks at their highest position. (4) Additional locations can be classified as required by the presence of other sources of flammable liquids on the berth, or by Coast Guard or other regulations.

~

Area Oassification for a Marine Terminal Handling Flammable Liquids. [30:Figure 29.3.22]

ARTICLE 516 Spray Application, Dipping, Coating, and Printing Processes Using Flammable or Combustible Materials

I nformational Note No. 1: For furmer information regarding safeguards for mese processes, such as fire protection, posting of warning signs, and maintenance, see NFPA 33-2018, Slandardfor Spray Apj1liwtion Using Flamnuww or Coml.mstibil: Malerials, and NFPA 34-2018, Standard for DijJjJing, Coating, and Printing Processes Using Hammabk or Combustibk Liquids. For additional information regarding ventilation, see NFPA 91-2015, Standard for Exhaust Sys/ems for Air Conveying of VajJOrs, Gases, Mists, and Particttlat,e Solids.

Part I. General 516.1 Scope. T his article covers the regular 01- frequent application of flammable liquids, combustible liquids, and combustible powders by spray operations and the application of flammable liquids or combustible liquids at temperanires above their flashpoint by spraying, dipping, coating, printing, or other means.

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Informational Note No. 2: Text mat is followed by a reference in brackets has been extracted from NFPA 33-2018, Standard for S/Jrrt)' A/JjJlication Using Fla111111able or Comlmslibk Malerials, or NFPA 34-2018, Standard/or Dipj1ing, Coating, and Printing Processes Using Flammabil: or Combttslibk Liquids. Only editorial changes were made to the extracted text to make it consistent with mis Code.

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516.3

ARTICLE 5 16- SPRAY APPLICATION, DIPPING, COATING, AND PRINTING PROCESSES

516.3 Class I Locations. Where the term Class I is used with 1·espect to Zone classifications within this article of the Code, it shall apply to Zone 0, Zone 1, and Zone 2 designations. Informational Note: The term Class /was originally included as a prefix 10 Zone 0, Zone I, and Zone 2 locations and references as an identifier for flammable gases, vapors, or liquids to differentiate from Class U and Class lll locations. Zone 0, Zone I, and Zone 2 only apply 10 flammable ga~es, vapors, or liquids so the Class I prefix is redundant and has been deleted, except for text that is extracted from other documents or to remain consistent throughout this article.

Part II. Open Containers 516.4 Area Classification. For open containers, supply containers, waste containe1·s, spray gun cleaners, and solvent distillation units that contain Class I liquids that are located in venti lated areas, area classification shal.I be in accordance with the following:

(1)

(2)

(3)

(4)

(5)

The area within 915 mm (3 ft) in all directions from any su ch container or equipment and extending to the floor or grade level shall be classified as Class 1, Division 1 or Class I, Zone 1, whichever is applicable. [33:6.5 .5.1 l The area extending 610 mm (2 ft) beyond the Division 1 or Zone 1 location shall be classified as Class I, Division 2 or Class 1, Zone 2, whichever is applicable . [33:6 .5.5.1 ] The area extending 1525 mm (5 ft) horizontally beyond the area described in 516.4(2) up to a height of 460 mm (18 in.) above the floor or grade level shall be classified as Class 1, Division 2 or Class 1, Zone 2, whichever is applicable. (33:6.5.5.1 ] The area inside any tank or container shall be classified as Class 1, Division l or Class 1, Zone 0, whichever is applicable. (33:6.5.5.1 ] Sumps, pits, or below grade channels within 3 .5 m (10 ft) horizontally of a vapor source shall be classified as Class 1, Division 1 or Zone 1. If the sump, pit, or chan nel extends beyond 3.5 m (10 ft) from the vapor source, it shall be provided with a vapor stop or it shall be classified as Class I, Division l or Zone 1 for its entire length.

For the purposes of electrical area classification, the Division system and the Zone system shall not be intermixed for any given source of release. (33:6.2.3]

915mm

.·._· ..

~-.-

""1~---3050 mm---J>Jo.11

i...l~c----3050 mm~ ( 1O ft)

(10 ft)

l..!:.._Ll

Class I, Division 1 or Zone 0 (e.g., vapor space in container)

D

Class I, Division 1 or Zone 1

ro-:i

Pit or trench

1?ZtJ Class I, Division 2 or Zone 2 FIGURE 516.4 Electrical Area Classification for Class I Liquid Operations Around Open Containers, Supply Containers, Waste Containers, Spray Gun Cleaners, and Solvent Distillation Units. [33:Figure 6.5.5.2]

(2) (3) (4) (5)

A Class I, Division 1 location shall be permitted to alternatively classified as a Class I , Zone 1 location. A Cla5s I, Division 2 location shall be permitted to alternatively classified as a Class I, Zone 2 location. A Class II, Division 1 location shall be permitted to alternatively classified as a Zone 21 location . A Class II, Division 2 location shall be permitted to alternative ly classified as a Zone 22 location . (33:6.2.2]

be be be be

(2) Classification Systems. For the purposes of electrical area classification, the Division system and the Zone system shall not be intermixed for any given somce of release. (33:6.2.3]

In instances of areas within the same facility classified separately, Class I, Zone 2 locations shall b e permitted to abut, but not overlap, Class 1, Division 2 locations. Class I, Zone 0 or Zone 1 locations shall not abut Class I, Division 1 or Division 2 locations. (33:6.2.4]

Elecu·ical wiring and utilization equipment installed in these areas shall be suitable for the location, as shown in Figure 516.4. (33:6.5 .5 .2]

(3) Equipment. Open flames, spark-producing equipment or processes, and equipment whose exposed surfaces exceed the autoignition temperature of the m aterial be ing sprayed shall not be located in a spray area or in a n y surrounding area that is classified as Division 2, Zone 2, or Zone 22. [33:6.2.5]

Part III. Spray Application Processes

Exception: This requirement shall not apply to d1ying, curing, m· fusing apparatus.

516.5 Area Classification. For spray application processes, the area classification is based on quantities of flammable vapo1·s, combustible mists, residues, dusts, or deposits that are present or might be present in quantities suffic ient to produce ignitable or explosive mixtures with a ir.

Any utilization equipment or apparatus that is capable of producing sparks or particles of hot meta l and th at is located above or adjacent to either the spray area or the surrounding Division 2, Zone 2, or Zone 22 areas shall be of the totally enclosed type or shall be constructed to prevent the escape of sparks o r particles of hot metal. (33:6.2.61

(A) Zone Classification of Locations. (1) Classification of Locations. The Zone system of electrical area classification shall be applied as follows: ( 1)

The inside of closed containers or vessels shall be considered a Class I, Zone 0 location.

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516.5

ARTICLE 516-SPRAY APPLICATION, DIPPING, COATING, AND PRINTING PROCESSES (B) Class I, Division 1 or Class I, Zone 0 Locations. The inte1-ior of any open or closed container 01- vessel of a flammable liquid shall be considered Class I, Division 1, or Class 1, Zone 0, as applicable. I nformational Note: For additional guidance, see Chapter 6 of NFPA 33-2018, Standard for SjJray Aj1plicalion Using Harmnable or Cornbustible Materials.

(C) Class I, Division l ; Class I, Zone I ; Class II, Division I; or Zone 21 Locations. The foll owing spaces shall be considered Class I, Division l; Class I, Zone l; Class II, Division l; or Zone 21 locations, as applicable:

(1) (2) (3) (4)

(5)

(6)

The interior of spray booths and rooms except as specifically provided in 516.5( D). The interior of exhaust ducts. Any area in the direct path of spray operations. Sumps, pits, or below grade channels within 7620 mm (25 ft) horizontally of a vapor source. If the sump, pit, or channel extends beyond 7620 mm (25 ft) from the vapor source, it shall be provided with a vapor stop or it shall be classified as C lass I, Division 1 for its entire length. (34:6.4.1] All space in all directions outside of but within 900 mm (3 ft) of open containers, supply containers, spray gun cleaners, and solvent distillation units containing flammable liquids. For limited finish ing workstations, the area inside the cmtains m partitions. [SeeFigwre516.5(D)(5).]

(D) Class I, Division 2; Class I, Zone 2; Class II, Division 2; or Zone 22 Locations. The spaces listed in 5 16.5(D )( l ) through (D)(5) shall be conside1-ed Class I, Division 2; Class I, Zone 2; Class II, Division 2; or Zone 22 as applicable . (1) Unenclosed Spray Processes. Elecu-ical wi ring and utilization equipment located outside but within 6100 mm (20 ft) horizontally and 3050 mm (10 ft) vertically of an enclosed spray area and not separated from the spray area by partition$ extending to the boundaries of the a1-ea designated as Division 2, Zone 2 or Zone 22 in Figure 516.5(D)( l ) shall be suitable for Class 1, Division 2; Class I, Zone 2; Class II, Division 2; or Zone 22 locations, whichever is applicable. [33:6.5.1 ] [See Figure 516.5(D)(l).] (2) Closed-Top, Open-Face, and Open-Front Spray Booths and Spray Rooms. If spray application operations are conducted within a closed-top, open-face, or open-front booth or room, as shown in Figure 5 16.5(D )(2), any electrical wiring or utilization equipment located outside of the booth or room but within 915 mm (3 ft) of any opening shal l be suitable for Cla5s I, Division 2; Class I, Zone 2; Class II, Divisio n 2; or Zone 22 locations, whic hever is applicable. The Class I, Division 2; Class I, Zone 2; CJa5s II, Division 2; or Zone 22 locations shown in Figure 516.5(D) (2) shall extend from the edges of the open face or open fro nt of the booth or room . (3) Open-Top Spray Booths. For spraying operations conducted within an open top spray booth, the space 915 mm (3 ft) vertically above the booth and within 915 mm (3 ft) of other booth openings shall be considered Class I, Division 2; Class I, Zone 2; Class II, Division 2; or Zone 22 whichever is applicable. [33:6.5.3]

2020 Edition

NATIONAL ELECTRICAL CODE

TOP (PLAN}

3050mm ( 10 ft)

Spray area

--

--

........

FRONT (ELEVATION}

I I Class I, Division 1; Class I, Zone 1; L___J Class II, Division 1; or Zone 21

17777J1 Class I, Division 2; Class I, Zone 2; ~ Class II, Division 2; or Zone 22

FIGURE 516.5(D)(l) Electrical Area Classification for Unenclosed Spray Areas. [33:Figure 6.5.1]

915mm (3 ft) radius

915mm (3 ft) radius

915 mm (3 ft) radius 915 mm (3 ft) radius

915 mm (3 ft) radius 915 mm (3 ft) radius

Open face

FIGURE 516.5(D)(2) Class I , Division 2; Class I, Zone 2; Class II, Division 2; or Zone 22 Locations Adjacent to a Closed Top, Open Face, or Open Front Spray Booth or Room. [33:Figure 6.5.2]

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516.5

ARTICLE 516- SPRAY APPLICATION, DIPPING, COATING, AND PRINTING PROCESSES

(4) Enclosed Spray Booths and Spray Rooms. For spray application operations confined to an enclosed spray booth or room, electrical area classification shall be as follows: (1)

(2)

(3)

(4)

The area within 915 mm (3 ft) of any opening shall be classified as Class I, Division 2; Class I, Zone 2; Class II, Division 2; or Zone 22 locations, whichever is applicable, as shown in Figure 516.5( D) (4) . '!\'here automated spray application equipment is used, the area out5ide the access doors shal l be unclassified provided the door interlock prevents the spray application operations when the door is open . "''here exhaust air is permitted to be recirculated, both of the following shall apply: a . T he interior of any recirculation path from the secondary particulate filters up to and including the air supply plenum shall be classified as Class I, Division 2; Class I, Zone 2; Class II, Division 2; or Zone 22 locations, whichever is applicable. b . The interior of fresh air supply ducts shall be unclassified. "''here exhaust air is not recirculated, the interior of fresh air supply ducts and fresh a ir supply plenums shall be unclassified.

drying apparan1s if the ai r temperanrre in the limited finish ing workstation exceeds the maximum discharge-air temperature allowed b y the standard that the h eater is listed to or 93°C (200°F), whichever is less. f33:14. 3.7.l ] (h) A means shall be provided to show that the limited finishing workstation is in the drying or cw-ing mode of operation and that the limited fin ishing workstation is to be unoccupied. [33:14.3.7.2] (i) Any containers of flammable or combustible liquids shall be removed from the li mited finishing workstation before the drying apparan1s is e nergized. f33:14.3.7.3] U) Portable spot-drying, curi ng, or fusion apparan1s shall be permitted to b e used in a limited finishing workstation, provided that it is not located within the hazardous (classified) location defined in 14.3.5 of NFPA 33 when spray application operations are being conducted. (33:14. 3.8] (k) Recirculation of exhaust air shall be permitted when the provisions of516.5(D )(4)(3) are both met. [33:14.3.9] 516.6 Wiring and Equipment in Class I Locations. (A) Wiring and Equipment - Vapors. All e lectrical wiring and equipment with in the Class I location (containing vapor only - not residues) defined in 516.5 shall comply with the applicable provisions of Article 501 or Article 505, as applicable .

f33:6.5.4l (5) Limited Finishing Workstations. (a) For limited finishing workstations, the area inside the 915 mm (3 ft) space horizontally and vertically beyond the volwne enclosed by the outside smface of the cmtains or partitions shall be classified as Class I, Division 2; Class I, Zone 2; Class II, Division 2; or Zone 22, as shown in Figure 516.5(D)(5) . (b) A limited finishing workstation shall be designed and constructed to have all of the following: ( 1) (2) (3) (4)

A dedicated make-up air supply Curtains or partitions that are noncombustible or limited combustible A dedicated mechanical exhaust and filu-ation system An approved automatic extinguishing system [33:14.3.1 ]

915 mm (3 ft) radius 915mm (3 ft) radius

r.===:!.~:IZZ~~===============;i

Enclosed spray booth or room (Class I, Division 1; Class I, Zone 1; Class II. Division 1; or Zone 21 within)

Informational Note: For limited combustible curtains or partitions see NFPA 701-2019, Sumdm·d Methods ofFire TeslSfor Flam'! Propagation of Textiles and Films.

(c) Th e amount of material sprayed in a limited finishing workstation shall not exceed 3.8 L (1 gal) in any 8-hour period . f33:14.3.2l (d) Curtains or partitions shall be fully closed during any spray operations. f33:14.3 .4l (e) The equipment within the limited finishing workstation shall be interlocked such that the spray application equipment cannot be operated unless the exhaust ventilation system is operating and functioning properly and spray application is automatically stopped if the exhaust venti lation system fails. (f) Any limited finishing workstation used for spray application operations shall not be used for any operation that is capable of producing sparks 01- particles of hot metal or for operations that involve open flames or elecu-ical utili zation equipment capable of producing sparks or particles of hot metal. f33:1 4.3.6l (g) ~ere industrial air heaters are used to e levate the a ir temperature for drying, curing, or fusing operations, a high limit switch shall be provided to automatically shut off the

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Extent of Class I, Division 2; Class I, Zone 2; Class II, Division 2; or Zone 22 area

915mm (3 ft) radius TOP VIEW AT CEILING LEVEL 915mm (3 ft) radius

915 mm (3 ft) radius 915mm (3 ft) radius

~

~

~"=================================='~

\

~

~

ELEVATION

For automated spray operations See 6.5.4(2)

FIGURE 516.5(D)(4) Class I, Division 2; Class I, Zone 2; Class II, Division 2; or Zone 22 Locations Adjacent to an Enclosed Spray Booth or Spray Room. [33:Figure 6.5.4] NATIONAL ELECTRICAL CODE

2020 Edi tion

ARTICLE 516-SPRAY APPLICATION, DIPPING, COATING, AND PRINTING PROCESSES

516.6

Dedicated mechanical exhaust system

,,/~

Air supply plenum

',

H. . . . . . . 1\

Curtains

1 1 ' ..... I I '

,,, ,,, ,, I I

'.!....... 915 mm (3 ft)

.................... ',

',>'',,,

Extent of Class I, Division 2; Class I, Zone 2; Class 11, Division 2 area; or Zone 22

I

''!...,

---- --

915mm (3ft)

915mm (3 ft)

TOP VIEW AT CEILING LEVEL

SIDE ELEVATION

END ELEVATION

FIGURE 516.5(D)(5) Class I, Division 2; Class I , Zone 2; Class II, Division 2; or Zone 22 Locations Adjacent to a Limited Finishing Workstation. [33:Figure 14.3.5.l] (B) Wiring and Equipment - Vapors and R esidues. Unless specifically listed for locations containing deposit5 of dangerous quantities of flamma ble or combustible vapors, mists, residues, dusts, or deposits (as applicable), there shall be no elecu·ical equipment in any spray area as herein defined whereon deposits of combustible residue could readily accumulate, except wiring in rigid metal conduit, intermediate metal conduit, Type MI cable, or in metal boxes or fittings containing no taps, splices, 01· te1·mina l connections. [33:6.4.21

(3)

(C) Illumination. Luminaires shall be permitted to be installed as fo llows:

(1)

(2)

Luminaires, like that shown in Figure 516.6(C) (a ), that are attached to the wal ls or ceiling of a spray area but that a1·e outside any classified area and are separated from the spray area by g lass panels shall be suitable for use in unclassified locations. Such fixtures shall be serviced from outside the spray a1·ea. f 33: 6.6.1] Luminaires, like that shown in Figure 516.6(C)(a), that are attached to the walls or ceiling of a spray area; that

2020 Edition

NATIONAL ELECTRICAL CODE

(4)

are separated from the spray area by glass panels and that are located within a Class I, Division 2; a C lass I, Zone 2; a Class II, Division 2; or a Zone 22 location sha ll be suitable for such location. Such fixtures shall be serviced from outside the spray area. f33:6 .6.2] Luminaires, like that shown in Figure 516.6(C)(b), that are an integral part of the walls or ceiling of a spray area sha ll be perm itted to be separated from the spray area by g lass panels that a1·e a n integral pa rt of the fixture. Such fixnires sha ll be listed for use in Class I, Division 2; Class I, Zone 2; Class II, Division 2; or Zone 22 locations, whichever is applicable, and a lso shall be listed for accumulations of deposits of combustible residues. Such fixtures shall be permitted to be serviced from inside the spray area. f33:6.6.3 ] Glass panels used to separate luminaires from the spray area or that are an integ ral part of the lumina ire shall meet the following requirements:

70-427

516.6

ARTICLE 5 16 - SPRAY APPLICATION, DIPPING, COATING, AND PRINTING PROCESSES a. Panels for light fixtures or for observation sha ll be of heat-u-eated glass, la minated glass, wired glass, or hammered-wired glass and shall be sealed to confine vapors, mists, residues, dusts, and deposits to the spray area. [33:5.5.1 l

Exterior of spray area

...

''

\

,l

,,,/~Hinged glass

b. Pane ls for light fixtures shall be separated from the fixnire to prevent the surface temperanire of the panel from exceeding 93°C (200°F). [33:5.5.2] c. The panel frame and method of attachment shall be designed to not fa il under fire exposure before the vision panel fails. [33:5.5.3)

Exception No. 1: Where portable el.ectric luminaires are required for operations in spaces not readily illuminated by fixed lighting within the spraying area, they shall be of the type identified for Class I, D ivision 1 or Class 1, Zone 1 locations where readily ignitible residues wuld be present. [33:6.9 Exception]

... ...

,, ,,

Exception: L isted spray booth assemblies that have vision panels constructed of other materials shall be pe1mitted.

(D) Portable Equipment. Poi-table e lectric luminaires or other utilization equipment shall not b e used in a spray area during spray operations.

Interior of spray area

f

Fixture mounted behind

f'

panel

Opening for fixture Mounting gasket

.Exception No. 2: Where portable electric drying apparatus is used in spray booths and the following requirements are met: (1)

(2) (3) (4)

The apparatus and its el.ectrical connections are not wcated within the spray enclosure during spray operations. Electrical equipment within 450 mm (18 in.) of the floor is identified for Class I, D ivision 2 or Class I, Zone 2 locations. All metallic parts of the d1)•ing apparatus are electrically bonded and grounded. Interlocks are provided to prevent the operation of spray equipment whil.e drying apparatus is within the spray enclosure, to allow for a 3-minute pinge of the enclosure bejore energizing the d1)1ing apparatus and to shut off drying apfJaratus on failure of ventilation system.

FIGURE 516.6(C)(b) Example of a Luminaire that is an Integral Part of the Spray Area and is Serviced from Inside the Spray Area. [33:Figure 6.6.3]

(E) Electrostatic Equipment. Elecu-ostatic spraying or detearing equipment shall b e installed and used only as provided in 516.10. Informational Note: For further information, see NFPA 33-2018,

Standard for Spray Application Using Flammable or CornbttStibk Materials.

Removable panel

(F) Static Electric Discharges. All persons a nd all elecu-ically conductive objects, including a ny metal parts of the process equipment 01- apparatus, containe rs of materia l, exhaust ducts, and piping systems that convey flammable or combustible liquids, shall be electrically grounded. (34:6.8.1]

516.7 Wiring and Equipment Not Within Classified Locations. (A) Wiring. All fixed wiring above the Class I and II locati ons shall be in metal raceways, Type PVC conduit, Type RTRC conduit, or electrical nonmetallic tubing; wh ere cables are used, they shall be Type MI, Type TC, or Type MC cable. Cellular me tal floor raceways sha ll o nly be permitted to supply ceiling outlets 01- as extensions to the area be low th e fl oor of a C lass I or II location . vVhe re cellula r metal raceways are used, they sha ll not have connections leading into or passing through the Class I or II location unless suitable seals a1·e provided. FIGURE 516.6(C)(a) Example of a Luminaire that is Mounted Outside of the Spray Area and is Serviced from Outside the Spray Area. [33:Figure 6.6.l] 70-428

NATIONAL ELECTRICAL CODE

2020 Edi tion

516.10

ARTICLE 516-SPRAY APPLICATION, DIPPING, COATING, AND PRINTING PROCESSES (B) Equipment. Equipment that could produce arcs, sparks, or particles of hot metal, such as lamps and lampholders for fixed lighting, cutouts, switches, receptacles, motors, or other equipment having make-and-break or sliding contacts, where installed above a classified location or a bove a location where freshly finished goods are handled, shal l be of the totally enclosed type or be constructed so as to prevent the escape of sparks or hot metal particles.

(6) Grounding. All elecu-ically conductive objects in the spray area, except tl10se objects required by the process to be at high voltage, shall be adequately grounded. This requirement shall apply to paint containers, wash cans, guards, hose conn ectors, b rackets, and any other elecu-ically conductive objects or devices in the a rea. Informational Nore: For more information on grounding and bonding for static electricity purposes, see NFPA 33-2018, Standani for Spray Ajplication Using Flmmnable or Combustible Materials; NFPA 34-201 8, Standard for Di/1/Ji'lig, Coating, and Printing Pmcesses Using Flammable or Combustible Liquids; and NFPA 77-2019, Recommended Practice on Static Electricity.

516.10 Special Equipment. (A) Fixed Electrostatic Equipment. This section shall apply to any equipment using elecu-ostatically charged e lements for the atomization, charging, and/ or precipitation of hazardous materials for coatings on articles or for other similar purposes in which the charging or atomizing device is attached to a mechanical support or manipulator. This shall include robotic devices. This section shall not a pply to devices that are held or manipulated by hand. Where robot or progrnmming procedures involve manual manipulation of the robot arm while spraying with the high voltage on, the provisions of 516.lO (B) shall apply. The installation of electrostatic spraying equipment shall comply with 516.lO(A)(l) through (A)(lO). Spray equipment shal.l be listed. All automatic electrostatic equipment systems shall comply with 516.6(A) through (F) .

( 1) Power and Control Equipment. Transformers, hig h-voltage supplies, control apparatus, and all other e lectrical portions of the equipment shall be installed outside of the Class I location or be of a type identified for the location.

l!.xception: High-voltage grids, electrodes, electrostatic atomizing heads, and their connections shall be permitted within the Class I location. (2) Electrostatic Equipment. Electrodes and e lecu-ostatic atomizing heads shall be adequately supported in permanent locations and shall be effectively insulated from ground. Electrodes and elecu-ostatic atomizing heads that are permanently attached to their bases, supports, reciprocators, or robots shall be deemed to comply with this section. (3) High-Voltage Leads. High-voltage leads sha ll be properly insulated and protected from mechanical damage o r exposure to desnuctive che mi cals. Any exposed e lement at hig h voltage shall be effectively and permanently supported on suitable insulators and shall be effectively guarded against accidental contact or grounding. (4) Suppor t of Goods. Goods being coated using this process shall be supported on conveyors or hangers. The conveyors or hangers shall be arranged (1) to ensure that the parts being coated are elecu-ically connected to ground with a resistance of 1 megohm or less and (2) to prevent parts from swinging. (5) Automatic Controls. Electrostatic apparntus shall be equipped with automatic means that will rapidly de-energize the hig h-voltage elements under any of the following conditions: (l) (2)

(3) (4)

Stoppage of ventilating fans or failure of ventilating equipment from any cause Stoppage of the conveyor carrying goods tl1rough the high-voltage field unless stoppage is required by the spray process Occurrence of excessive current leakage at any point in the high-voltage system D e-energizing the primary voltage input to the power supply

2020 Edition

NATIONAL ELECTRICAL CODE

(7) Isolation. Safeguards such as adequate booths, fencing, railings, interlocks, or other means shall be placed about the equipment or in corporated therein so that they, either by their location, character, or both, ensure that a safe separation of the process is maintained. (8) Signs. Signs shall be conspicuously posted to convey the following: (1) (2) (3)

Designate the process zone as dangerous with regard to fire and accident Identify the grounding requirements for all e lecu-ically conductive objects in the spray area Resu-ict access to qualified personnel only

(9) Insulators. All insu lators shall be kept clean a nd dry. (10) Other Than Nonincendive Equipment. Spray equipment that cannot be cla~sified as nonincendive shall comply with 516.lO(A)(lO)(a) and (A)( lO)( b) . (a) Conveyors, hangers, and application equipment shall be arranged so that a minimum separation of at least twice the sparking distance is maintained between the workpiece or material being sprayed and e lecu-odes, electrostatic atomizing heads, or charged conductors. Warnings defining this safe distance shall be posted. [33:11.4.1] (b) The equipment shall provide an automatic means of rapidly de-energizing the high-voltage elements in the event the distance between the goods being painted and the electrcr des or elecu-ostatic atomizing heads falls below that specified in 516.lO (A)(lO)(a) . [33:11 .3.8] (B) Hand-Spraying Electrostatic Equipment. This section shall apply to any equipment using e lecu-ostatically charged elements for the atomization, charging, or precipitation of flammable and combustible materials for coatings on articles, or for other sim ilar purposes in whi ch the c ha rging or atomizing device is hand-held and manipulated during the sprayi ng operation. Elecu-ostatic hand-spraying equipment and devices used in connection with paint-spraying operations shall be of listed types and shall comply with 516.lO (B)(l) through (B) (5) .

(1) General. The high-voltage circuits sha ll be designed so as not to produce a spark of sufficient intensity to ignite the most readily ig ni tible of those vapor-ai1- mixtures likely to be encountered or result in appreciable shock hazard upon coming in contact with a grounded object under all norma l operating conditions. The elecu-ostatically charged exposed elements of the handgun shall be capable of being energized only by an actuator that also controls the coating material supply. (2) Power Eq uipmen t. Transformers, power packs, conu-ol apparatus, and a ll other e lectrical portions of the equipment

70-429

516.10

ARTICLE 5 16- SPRAY APPLICATION, DIPPING, COATING, AND PRINTING PROCESSES

shall be located outside of the Class I location or be identified for the location. Exception: The handgun itself and its connections to the power supply shall be permitted within the Class I l.ocation.

(3) Handle. The handle of the spraying gun shall be elecu·ically connected to ground by a conductive material and be consu·ucted so that the operator in normal operating position is in elecu·ical contact with the grounded handle with a 1·esistance of not more than 1 megohm to prevent buildup of a static charge on the operator's body. Signs indicating the necessity for grounding other persons entering the spray area shall be conspicuously posted. (4) Electrostatic Equipment. All electrically conductive objects in the spraying area, except those object5 1·equired by the process to be at high voltage shall be electrically connected to ground with a resistance of not more than 1 megohm . This 1·equirement shal l apply to paint containers, wash cans, and any other elecu-ical conductive objects or devices in the area. The equipment shall carry a prominent, permanently installed warning regarding the necessity for this grounding feature. Informational Note: For more information on grounding and bonding for static electricity purposes, see NFPA 33-2018, Slandanl for Sj1my Aj1plicalion Using Hammable or Combuslible Malerials; NF'PA 34-2018, Slandard for Dipping, Coaling, and Prinling Processes Using flammable or Combuslible Liquids; and NFPA 77-2019, Recommended Practice on Slalic Elec11icil)'·

(5) Support of Objects. Objects being painted shall be maintained in elecu·ical contact with the conveyor or other grounded support. Hooks shall be regularly cleaned to ensure adequate grounding of 1 megohm or less. Areas of contact shall be sharp point~ or knife edges where possible. Point~ of suppon of the obj ect shall be concealed from random spray where feasible, and, where the objects being sprayed are supported from a conveyor, tl1e point of attachment to the conveyor shall b e located so as to not collect spray material during normal operation. (C) Powder Coating. This section shall apply to processes in which combustible dry powders are applied. The hazards associated with combustible dust5 are present in such a process to a degree, depending on the chemical composition of the mate1·ial, particle size, shape, and distribution .

(1) Electrical Equipment and Sources of Ignition. Electrical equipment and other sources of ignition shall comply with the 1·equirements of Article 502. Portable electric luminaires and otl1er utilization equipment shall not be used within a Class II location during operation of the finishing processes. V\There such luminaires or utilization equipment are used during cleaning or repairing operations, they shall be of a type identified for Class II, Division 1 locations, and all exposed metal parts shall be connected to an equipment grounding conductor.

(2) Fixed Electrostatic Spraying Equipment. The provisions of 516.lO(A) and 516.lO (C) (1) shall apply to fixed elecu-ostatic spraying equipment. (3) Electrostatic Hand-Spraying Equipment. The provisions of 516.lO(B) and 516.lO(C)( l ) shall apply to elecu·ostatic handspraying equipment. (4) Electrostatic Fluidized Beds. Elecu-ostatic fluidized beds and associated equipment shall be of identified types. The high-voltage circuits shall be designed such that any discharge produced when the charging electrodes of the bed are approached or contacted by a grounded object shall not be of sufficient intensity to ignite any powder-air mixture likely to be encountered or to result in an appreciable shock hazard. (a) Transformers, power packs, control apparatus, and all other elecu-ical portions of the equipment shall be located outside the powder-coating area or shall otherwise comply with the requirements of 516. lO(C) (1). Exception: The charging e!.ectrodes and their connections to the power supply shall be permitted within the powder-coating area.

(b) Ali elecu·ically conductive objects within the powdercoating area shall be adequately grounded. The powdercoating equipment shall carry a prominent, permanently installed warning regarding the necessity fo1· grounding these objects. Informational Note: For more information on grounding and bonding for static electricity purposes, see NF'PA 33-2018, Slandanl for Spray Af1jllicalion Using Flammable or Combustible Materials, NF'PA 34-2018,, Slandard for Dif>jJing, Coaling, and Prinling Processes Using Hmnmable or Combuslible Liquids; and NF'PA 77-2019, Recommended Praelice on Slalic Eleelricily.

(c) Objects being coated shall be maintain ed in electrical contact (less than 1 megohm) with th e conveyor or other support in order to ensure proper grounding. Hangers shall be regularly cleaned to ensure effective electrical contact. Areas of e lecu-ical contact shall be sharp points or knife edges where possible. (cl) The elecu·ical equipment and compressed a ir supplies shall be interlocked with a ventilation system so that tile equipment cannot be operated unless the ventilating fans are in operation . f33:Chapter 15] 516.16 Grounding. All metal raceways, the metal armors 01· metallic sheath on cables, and all non-current-carrying metal parts of fixed or portable electrical equipment, regardless of voltage, shall be grounded and bonded. Grounding a nd bonding shall comply with 501.30, 502.30, or 505.25, as applicable.

Exception: YI/here portable elect1ic luminaires are required for operations in spaces not readily illuminated by fixed lighting within the spraying area, they shall be of the type listed for Class II, Division 1 locations where readily ignitible residues may be present.

70-430

NATIONAL ELECTRICAL CODE

2020 Edition

ARTICLE 5 16-SP RAY APPLICATION, DIPPING, COAT ING, AND P RINTING PROCESSES Part IV. Spray Application Operations in Membrane Enclsures

sures. See also NFPA 70 1-2019, Standard Methods of Fire Tests for Flame Proj;ag(ition of Textiles and Films, Test Method 2 for construction information.

516.18 Area Classification for Temporary Membrane Enclosures. Electrical area classification shall be as follows: ( 1) (2)

T he area with in the membrane enclosme shall be considered a Class I, Division 1 a rea, as shown in Figure 516.18. A 1.5 m (5 ft) zone o u tside of the membrane enclosure shall be considered Class I, Division 2, as sh own in Figure 5 16.18.

Informational Note No. 1: The risks to people and property are unique when spray painting within the confined spaces of temporary membrane enclosures. See NFPA 33-2018, Standard for Sj;ray Application Using Flmnmabk or Combustibk Malcrial~, for information on occupancy, ventilation, fire protection, and permitting for spray application operations in membrane enclosures. NFPA 33-2018 limits spray application operations within both outdoor and indoor temporary membrane enclosures, as well as use and time constraints. lnformarional Note No. 2: Section 18.6 of NFPA 33-2018, Standard for Sf;ray Af;f;lication Using Jilammable or Conwustibk Materials, limits material used in a vertical p lane for membrane enclo-

516.23

Informational Note No. 3: See 18.3.2.l.l of NFPA 33-2018, Standanl for Sj;ray Application Using Flmnmabk or Combusti.bk Mauria~, for membrane installation beneath sprinklers. See a lso 8.15.1.5 of NFPA 13-2019, Standard for the Installation of Sprinkler Systems, for protection of membrane strucmres.

516.23 Electrical and Other Sources of Ignition. Electrical wiring and utilizatio n equipm ent used within d1e classified areas inside and o utside of me m bran e enclosures d u ring spray painting shall be suitable for the location a nd shall com ply wiili all of the following: (1) (2) (3) (4)

All power to lie workpiece sha ll be re moved during spray painting. Workpieces shall be grounded . Spray paint eq uipment shall b e grounded. Scaffolding shall be bonded to th e workpiece and grounded by an approved method.

PLAN VIEW

ELEVATION

FIGURE 516.18 Electrical Classifications for Temporary Outdoor Membrane Enclosures [33:Figure 18.7.1.1] 2020 Edition

NATIONAL ELECTRICAL CODE

70-431

516.29

ARTICLE 5 16- SPRAY APPLICATION, DIPPING, COATING, AND PRINTING PROCESSES

Part V. Printing, Dipping, and Coating Processes 516.29 Classification of Locations. Classification is based on quantities of flammable vapors, combustible mists, residues, dust5, or deposit5 that are present or might be present in quantities sufficient to produce ignitable or explosive mixtures with air. Electrical wiring and electrical utilization equipment located adjacent to open processes shall comply with the requirements as follows. Examples of these requirements are illuSU"ated in Figure 516.29(a), Figure 516.29(b), Figure 516.29(c), and Figure 516.29(d) . Informational Note: For additional guidance, see Chapter 6 of NFPA 33-2018, Standard for SjJray AjJpliwtion Using Flarmnable or CornbtlSlible Maurials, and Chapter 6 of NFPA 34-WlS, Standard for DijJ/Jing, Coating, and Printing Processes Using Flamrnable or Combustible Liquids.

(I )

(2)

(3)

(4)

Electrical wiring and electrical utilization equipment located in any sump, pit, or below grade channel that is within 7620 mm (25 ft) hmizontally of a vapor source, as defined by this standard, shall be suitable for Class I, Division 1 or Class I, Zone 1 locations. If the sump, pit, or channel extends beyond 7620 mm (25 ft) of the vapor source, it shall be provided with a vapor stop, or it shall be classified as Class I, Division 1 or Class I, Zone 1 for it5 entire length. f 34:6.4. l l Electrical wiring and electrical utilization equipment located within 1525 mm (5 ft) ofa vapor source shall be suitable for Class I, Division 1 or Class I, Zone 1 locations. The space inside a d ip tank, ink fountain, ink reservoir, or ink tank shall b e classified as Class I, Division 1 or Class J, Zone 0, whichever is applicable. Electrical wiring and electrical utilization equipment located within 915 mm (3 ft) of the Class I, Division 1 or Class I, Zone 1 location shall be suitabl e for Class I, Division 2 or C lass I, Zone 2 locations, whichever is applicable. The space 915 mm (3 ft) above the floor and extending 6100 mm (20 ft) horizontally in all directions from the Class I, Division 1 or Class I, Zone 1 location shall be clas-

(5)

sified as Cla5s I, Division 2 or Class I, Zone 2, and electrical wiring and elecu·ical utilization equipment located within this space shall be suitable for Class I, Division 2 or Class I, Zone 2 locations, whichever is applicable. This space shall be permitted to be nonclassified for purposes of electrical installations if the surface area of the vapor source does not exceed 0.5 m 2 (5 ft2 ), the contents of the dip tank, ink fountain, ink reservoir, 01· ink tank do not exceed 19 L (5 gal), and the vapor concentration during operating and shutdown periods does not exceed 25 percent of the lower flammable limit.

516.35 Areas Adjacent to Enclosed Dipping and Coating Processes. Areas adjacent to enclosed dipping and coating processes are illustrated by Figure 5 16.35 and shall be classified as fo ll ows: (1)

(2)

(3)

The interim· of any enclosed dipping or coating process or apparatus shall be a Class I, Division 1 or Class I, Zone 1 location, and electrical wiring and electrical utilization equipment located within this space shal l be suitable for Class I, Division 1 or Class I, Zone 1 locations, whichever is applicable. The area inside the dip tank shall be classified as Class I, Division 1 or Class I, Zone 0, whichever is applicable. The space within 915 mm (3 ft) in all directions from any opening in the enclosure and extending to the floor 0 1· grade level shall be classified as Class I, Division 2 or Class I, Zone 2, and elecu·ical wiring and elecu·ical utilization equipment located within this space shall be suitable for Class I, Division 2 locations o r Class I, Zone 2 locations, whichever is applicable . All other spaces adjacent to an enclosed d ipping 01· coating process or apparatus shall be classified as nonhazardous for purposes of electrical installations.

516.36 Equipment and Containers in Ventilated Areas. Open containers, supply containers, waste containers, and solvent distillation units that contain Class I liquids shall be located in areas ventilated in accordance with 516.4.

Conveyor rail 915 mm (3ft)

915 mm (3ft)

1525 mm (5ft)

915mm (3 ft)

915mm~ (3 ft) 6100 mm (20 ft)

c:::::::::;J

ill 1525mm 1525 mm (5 ft)

(5 ft)

915 mm (3 ft)

Fl

1525 mm (5 ft) +--- 6100 mm (20 ft)

Class I, Division 1 or Zone 0

c=I Class I, Division 1 or Zone 1 IZZll!

Class I, Division 2 or Zone 2

FIGURE 516.29(a) Electrical Area Classification for Open Dipping and Coating Processes Without Vapor Containment or Ventilation. [34:Figure 6.4(a)] 70-432

NATIONAL ELECTRICAL CODE

2020 Edition

ARTICLE 516-SPRAY APPLICATION, DIPPING, COATING, AND PRINTING PROCESSES

516.38

Saturated vapor blanket

Peripheral vapor ventilation

Exhaust plenum Vapor· condensing coils

Ventilation inlet at floor level

CZ]

Class I, Division 1 or Zone O

D

Class I, Division 1 or Zone 1

Pit

D

Class I, Division 1 or Zone O

D

Class I, Division 1 or Zone 1

IZQI Class I, Division 2 or Zone 2 FIGURE 516.29(d) Electrical Area Classification for a Typical Printing Process. [34:Figure 6.4(d)]

~ Class I. Division 2 or Zone 2 Definitions Freeboard: The distance from the maximum solvent or coating material level to the top of the tank Freeboard ratio: The freeboard height divided by the smaller of the interior length or interior width of the tank

FIGURE 516.29(b) Electrical Area Classification for Open Dipping and Coating Processes with Peripheral Vapor Containment and Ventilation - Vapors Confined to Process Equipment. [34:Figure 6.4(b)]

516.37 Luminaires. For printing, coating, and dipping equipment where the process area is enclosed by g lass panels that are sealed to confine vapors a nd mists to the inside of the enclosure, luminaires that are attached to the walls or ceilings of a process enclosw-e and that are located out5ide of a n y classified area shall be permitted to be of general purpose construction. Such luminaires shall be serviced from outside the enclosure. Luminaires that are attached to the walls or ceilings of a process enclosure, are located within the Class I, Division 2 or Class I, Zone 2 location, and are separated from the process area by glass panels that are sealed to confine vapors and 1nists shall be suitable for use in that location. Such fixtures shall be serviced from outside the enclosure. 516.38 Wiring and Equipment Not Within Classified Locations. (A) Wiring. All fixed wiring above the Class I and II locations shall be in metal raceways, Type PVC conduit, Type RTRC conduit, or e lectrical nonmetallic tubing; where cables are used, they shall be Type MI, Type TC, or Type MC cable . Cellular metal floor raceways sha ll only be permitted to supply ceiling outlets or as extensions to the area below the floo1- of a Class I or II location. '!\There cellular metal raceways are used, they shall not have connections leading into or passing through the Class I or II location unless suitable seals are p1-ovided.

I!.' .(j Class I, Division 1 or Zone O

D

Class I, Division 1 or Zone 1

(B) Equipment. Equipment that is capable of producing arcs, sparks, or particles of hot metal, such as lamps and lampholders for fixed lighting, cutouts, switches, receptacles, motors, o r other equipment having make-and-break or sliding contact5, where installed above a classified location or above a location where freshly finished goods are handled, shall be of the totally enclosed type or be constructed so as to prevent the escape of sparks or hot metal particles.

~ Class I, Division 2 or Zone 2

FIGURE 516.29(c) Electrical Area Classification for Open Dipping and Coating Processes with Partial Peripheral Vapor Containment and Ventilation - Vapors NOT Confined to Process Equipment. [34:Figure 6.4(c)]

2020 Edition

NATIONAL ELECTRICAL CODE

70-433

ARTICLE 517 - HEALTH CARE FACILITIES

516.40

Vapor confined to enclosed tunnel

Enclosed vapor/drain tunnel

Oven

915 mm+-.J~='I====" (3ft)

Vapor space

Classification of interior of oven governed by NFPA 86

[::::::;] Class I, Division 1 or Zone 0 915mm 915mm (3ft) (3ft)

FIGURE 516.35 [34:Figure 6.5]

[=:=J Class I, Division 1 or Zone 1 ~ Class I, Division 2 or Zone 2

Electrical Area Classification Around Enclosed Dipping and Coating Processes.

516.40 Static Electric Discharges. All persons and all electrically conductive objects, including any metal parts of the process equipment or apparatus, containers of material, exhaust ducts, and piping systems that convey flammable or combustible liquids, shall be electrically grounded. Provision shall be made to dissipate static electric charges from all nonconductive substrates in printing processes. Informational Note: For add itional guidance on reducing the risk of ignition from electrostatic discharges, see NFPA 77-2019,

Recomnumded Practice on Static Electricity.

changes were made with this Corle.

tO

the extracted text

tO

make it consistent

517.2 Definitions. The defin itions in this section shall apply only within this article. Alternate Power Source. One or more generator sets, or battery systems where permitted, intended to provide power during the interruption of the normal electrical service; or the public utility electrical service intended to provide power during interruption of service normally provided by the generating facilities on the premises. r99:3.3.4] Ambulatory Health Care Occupancy. An occupancy used to provide services or treaunent simultaneously to four or more patients that provides, on an outpatient basis, one or more of the following:

ARTICLE 517 Health Care Facilities

Part I. General 517.1 Scope. This article applies to electrical construction and installation criteria in health care facilities that provide services to human beings. The requirements in Parts II and III not only apply to singlefunction buildings but are also intended to be individually applied to their respective forms of occupancy within a multifunction building (e.g., a doctor's examining room located within a limited care facility would be required to meet 517.10). Informational Note No. l : For information concerning performance, maintenance, and testing criteria, refer to the appropriate health care facilities documenrs. Info rmational Note No. 2: Text that is followed by a reference in brackets has been extrncted from NFPA 99-2018, Health Care Facilities Code, and NFPA 101-2018, Life Safety Code. Only editoria l

70-434

(1)

Treatment for patients that renders the patients incapable of taking action for self-preservation under emergency conditions with out the assistance of others. (2) Anesthesia that renders the patients incapable of taking action for self-preservation under emergency conditi ons without the assistance of others. (3) Treatment fo1· patients who, due to the nature of the ir injury or illness, are incapable of taking action for selfpreservation under emergency conditions \vithout the assistance of others. [101:3.3.196.1 J Anesthetizing Location. Any area of a faci lity that has been designated to be used for the administration of any flammable or nonflammable inhalation anesthetic agen t in the course of examination or u·eatment, including the use of such agent5 for relative analgesia. Battery-Powered Lighting Units. Individual unit equipment for backup illumination consisting of the following: (1)

(2)

Rechargeable battery Battery-charging means

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ARTICLE 51 7 - HEALTH CARE FAGILITIES (3) (4)

Provisions for one or more lamps mounted on the equipment, or with terminals for remote lamps, 01· both Relaying device arranged to energize the lamps automatically upon failure of the supply to the unit equipment

Critical Branch. A system offeeder·s and branch circuits supplying power for task illumination, fixed equipment, select receptacles, and select power circuit5 serving areas and functions related to patient care that are automatically connected to alternate power sources by one or more u-ansfer switches during interruption of the normal power source. r99:3.3 .30l

Monitor Hazard Current. The hazard current of the li ne isolation monitor alone. (99:3.3.70.21 'Total Hazard Current. The hazard current of a g iven isolated system with all devices, including the line isolation monitor, connected. [99:3 .3.70.3 ] Health Care Facilities. Buildings, portions of buildings, or mobile enclosures in which human medi cal, dental, psychiau-ic, nursing, obsteu-ical, or smgical care is provided. [ 99:3 .3.71] Informational Note: Examples of health care facilities include, but are nor limited to, hospitals, nursing homes, limited care facilit.ies, clinics, medical and dental offices, and ambulatory care centers, whether permanent or movable.

Dental Office. A building or part thereof in which the following occur: (1)

Examinations and minor u·eatments/ procedures performed under the continuous supervision of a dental professional; (2) Use of limited to minimal sedation and treatment or procedures that do not render the patient in capable of self~p re servation under emergency conditions; and (3) No overnight stays fo1· patient5 or 24-hom operations. r99:3.3 .38l Electrical Life-Support F.quipment. Elecu-ically powered equipment whose continuous operation is necessary to maintain a patient's life. [99:3.3.45) Equipment Branch. A system of feeders and branch circuits arranged fo1· delayed, automatic, or manual connection to the alternate power source and that serves primarily 3-phase power equipment. [99:3 .3.491 Essential Electrical System. A system comp1·ised of alternate sources of power and all connected disu·ibution systems and ancillary equipment, designed to ensure continuity of electrical power to designated areas and functions of a health care facility during disruption of normal power sources, and also to minimize disruption within the internal wiring system. [99:3.3.51] Exposed Conductive Surfaces. Those surfaces that are capable of carrying elecu·ic current and that are unprotected, uninsulated, unenclosed, or unguarded, permitting personal contact. r99:3.3.53J Informational Note: Paint, anodizing, and similar coatings are not considered suitable insulation, unless they are listed for such use.

Fault Hazard Current. See Hazard Current. Flammable Anesthe tics. Gases or vapors, such as fluroxene, cyclopropane, divinyl ether, ethyl chloride, ethyl ether, and ethylene, which may form flammable or explosive mi.xttn-es with air, oxygen, or reducing gases such as niu-ous oxide. Flammable Anesthetizing Location. Any area of the facility that has been designated to be used for the adminisu-ation of any flammable inhalation anesd1etic agents in the normal course of examination or u-eatment. Hazard Current. For a g iven set of connections in an isolated power system , the total current that would flow through a low impedance if it were connected between either isolated conductor and ground. r99:3.3.70J

Fault Hazard Ci1rrent. The hazard current of a given isolated power system with all devices connected except the line isolation monito1·. f99:3.3.70. l ]

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517.2

Health Care Facility's Governing Body. The person or persons who have the overall legal responsibility for the operation of a health care facility. [99:3.3.72] Hospital. A building or portion thereof used on a 24-hour basis for the medical, psychiau·ic, obstetrical, or surgical care of four or more inpatient5. [101:3.3.150] Invasive Procedure. Any procedure that peneu-ates the protective surfaces of a patient's body (i.e ., skin, mucous membrane, cornea) and that is performed with an aseptic field (procedural site). [Not included in m is category are placement of peripheral intravenous needles or catheters used to administer fluids and/ or medications, gasu·ointestinal endoscopies (i .e ., sigmoidoscopies), insertion of urethral catheters, and o ther similar procedures.] [99:3.3.871 Isolated Power System. A syste m comprising an isolating transformer or its equivalent, a line isolation monitot~ and its ungrounded circuit conductors. [99:3.3 .891 Isolation Transformer. A transfo1·mer of the multiple-winding type, with the primary and secondary windings physically sepac rated, that inductively couples its ungrounded secondary winding(s) to the grounded feeder system that energizes its primary winding(s) . [99:3 .3 .90) Life Safety Branch. A system of feeders and branch c ircuits supplying power for lighting, receptacles, and equipment essential for life safety drnt is automatically connected to a lternate power sources by one or more transfer switches during i nterruption ofd1e normal power somce . [99:3.3 .931 Limited Care Facility. A building or portion thereof used o n a 24-hour basis for the housing of four or more persons who are incapable of self-preservation because of age; physical limitation due to accident or illness; or limitations such as inte llectual disabi lity/ developmental disabil ity, mental illness, o r chemical dependency. Line Isolation Monitor. A test insu·ument designed to continually check the balanced and unbalanced impedance from each line of an isolated circuit to ground and equipped wi th a builtin test circuit to exercise the alarm without adding to the leakage current hazard. [99:3.3.951 Medical Office. A building or part thereof in whi ch the fo llowing occur: (1)

Examinations and mi.nor treaunent5/ procedtu-es are performed under the continuous supervision of a medical professional;

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ARTICLE 517 - HEALTH CARE FACILITIES

The use of limited to minimal sedation and treaunent or procedures that do not rende1· the patient incapable of self-preservation tmder emergency conditions; and (3) No overnight stays for patients or 24-hour operations. [99:3.3.1061 (2)

Monitor Hazard Current. See Hazard Current. Nurses' Stations. Areas intended to provide a center of nursing activity for a group of nurses serving bed patients, where the patient calls are received, nurses are dispatched, nurses' notes written, inpatient charts prepared, and medications prepared for disu·ibution to patients. Whe1·e such activities are carried on in more than one location within a nursing unit, all such separate areas are considered a part of the nurses' station. Nursing Home. A building or portion of a building used on a 24-hour basis for the housing and nursing care of four or more persons who, because of mental or physical incapacity, might be unable to provide for their own needs and safety without the assistance of another person . [JOI :3.3.148.2]

Categ01y 4 (Supp01·t) Space. Space in which failu re of equipment or a system is not likely to have a physical impact on patient care. (99:3.3.136.4) Informational Note: Category 4 spaces were formerly known as support rooms. Examples of support spaces include, but are nor limited to, anesthesia work rooms, sterile supply, laboratories, morgues, waiting rooms, utility rooms, and lounges. [99:A.

3.3.136.4)

Patient Care Vicinity. A space, within a location intended foithe examination and treatment of patients, extending 1.8 m (6 ft) beyond the normal location of the bed, chair, table, u-eadmill, or other device that supports the patient during examination and treatment and extending vertically to 2.3 m (7 ft 6 in.) above the floor. [99:3.3.1 39] Patient Equipment Grounding Point. A jack or terminal that serves as the collection point for redundant grounding of e lectric appliances serving a patient care vicinity or for grounding other items in order to el iminate e lectromagnetic interference problems. [99:3.3.140)

Patient Bed Location. The location of a patient sleeping bed, or the bed or procedtffe table of a Category 1 (critical care) space. (99:3.3.135]

Psychiatric Hospital. A building used exclusively for the psychiatric care, on a 24-hour basis, of four or more inpatients.

Patient Care Space. Any space of a health care facility wherein patients are intended to be examined or treated. [99:3.3.1 36]

Reference Grounding Point. The ground bus of the panelboard or isolated power syste m panel supplying the patient care room. [99:3.3.154)

Informational Note No. l: The health care facility's governing body designates patient care space in accordance with the type of patient care anticipated. Informational Note No. 2: Business offices, corridors, lounges, clay rooms, dining rooms, or similar areas typically are not classified as patient care spaces. [99:A.3.3. l36]

Category 1 (Critical Care) Space. Space in which failure of equipment or a system is likely to cause major injury or death of patients, staff, or visito1·s. [99:3.3.1 36.1 ] Informational Note: Category 1 spaces, formerly known as critical care rooms, are typically where patients are intended to be subjected to invasive procedures and connected to lineoperated, patient care-related appliances. Examples include, but are not limited to, special care patient rooms used for critical care, intensive care, and special care treatment rooms such as angiography laboratories, cardiac catheterization laboratories, delivery rooms, operating rooms, post-anesthesia care units, trauma rooms, and other similar rooms. [99:A.3.3.136. l]

Category 2 (General Care) Space. Space i.n which failure of equipment or a system is likely to cause minor injury to patients, staff, or visitors. (99:3.3.1 36.21 Informational Note: Category 2 spaces were formerly known a~ general care rooms. Examples include, but are nor limited to, inpatient bedrooms, dialysis rooms, in vitro fertilization rooms, procedtu-al rooms, and similar rooms. [99:A.3.3.1 36.2]

Category 3 (Basic Care) Space. Space in which failure of equipment or a system is not likely to cause irtjury to the patients, staff, or visitors but can cause patient discomfort. (99:3.3 .1 36.3] Informational Nore: Category 3 spaces, formerly known as basic care rooms, are typically where basic medical or dental care, treatment, or examinations are performed. Examples include, but are not limited to, examination or tream1enr rooms in clinics, medical and dental offices, nursing homes, and limited care facilities. [99:A.3.3.136.3)

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Relative Analgesia. A state of sedation and partial block of pain perception produced in a patient by the inhalation of concentrations of nitrous oxide insufficient to produce loss of consciousness (conscious sedation). Selected Receptacles. A minimal number of receptacles selected by the health care facility's governing body as necessary to provide essential patient care and facility services during loss of normal power. (99:3.3.160] Task Illumination. Provisions for the minimum lighting required to carry out necessary tasks in the areas described in 517.34, including safe access to supplies and equipment and access to exits. [99:3.3.1731 Wet Procedure Location. The area in a patient care space where a procedure is perfo1·med that is normally subject to wet conditions while patients are present, including standing fluids on the floor or drenching of the work area, either of which condition is intimate to the patient or staff. [99:3.3.1831 Informational Note: Routine housekeeping procedures and incidental spillage of liquids do not define a wet procedure location. [99:A.3.3.183]

X-Ray Installations, Long-Time Rating. A rating based on an operating interval of 5 minutes 01· longei-. X-Ray Installations, Mobile. X-ray equipment mounted on a permanent base wid1 wheels, castei·s, or a combination of both to facilitate moving the equipment while completely assembled. X-Ray Installations, Momentary Rating. A rating based on an operating interval that does not exceed 5 seconds. X-Ray Installations, Portable. X-ray equipment designed to be hand carried. X-Ray Installations, Transportable. X-rny equipment to be conveyed by a vehicle or that is readily disassembled for transport by a vehicle.

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ARTICLE 51 7 - HEALTH CARE FAGILITIES Part II. Wiring and Protection

517.10 Applicability. (A) Applicability. Part II shal l apply to patient care space of all health care facilities. (B) Not Covered. Part II shall not apply to the following: (l)

(2 )

(3)

Business offices, corridors, waiting rooms, and the like in clinics, medical and dental offices, and outpatient facilities Areas of nursing homes and limited care facilities wired in accordance with Chapters 1 thrnugh 4 of this Code where these areas are used exclusively as patient sleeping rooms Areas used exclusively for any of the following purposes: a. b. c. d.

Intramuscular iruections (immunizations) Psychiauy and psychotherapy Alternative medicine Optom etry

Informational Note: See NFPA 101-2018, Life Sa/el)' Code.

517.11 General Installation Construction Criteria. The purpose of this article is to specify the installation criteria a nd wiring methods that minimize elecu·ical hazards by the maintenan ce of adequately low potential differences only between exposed conductive surfaces that are likely to become energ ized and could be contacted by a patient. Informational Note: In a health care facility, it is d ifficult to prevent the occurrence of a conductive or capacitive path from the patient's body to some grounded objecr, because that path may be established accidemally or through instrumentation directly connected ro the patient. Other e lectrical ly conductive surfaces that may make an additional comact with the patienr, or instruments d1at may be connected to d1e patient, d1en become possible sources of e lectric currents th at can traverse the patiem·s body. The hazard is increased as more apparatus is associated with the patient, and, d1erefore, more intensive precautions a re needed. Control of electric shock hazard requires the li mitation of electric current that might flow in an electrical circuit involving the patient's body by raising the resistance of the conductive circuit that includes the patient, or by insulating exposed surfaces that might become energized, in addition to reducing the potential difference that can appear between exposed conductive surfaces in the patient care vic inity, o r b y combinations of these methods. A special problem is presented by the patient with an externalized di rect conductive path to the heart muscle. The patient may be eleCLrocuted at current levels so low drnt additional protection in the design of appliances, insulation of the cad1eter, and control of medical practice is required.

517.16

(B) Insulated Equipment Grounding Conductors and Insulated Equipment Bonding Jumpers.

(1) General. The followi ng shall be directly connected to an insulated copper equipment grounding conductor that is clearly identified along its entire le ngth by green insulation and installed with the branch circuit conductors in the wiring methods as provided in 517.1 3(A) : (1) (2) (3)

(4)

The grounding terminals of a ll receptacles other than isolated ground receptacles Metal outlet boxes, metal device boxes, or metal ender su res All non-current-canying conductive surfaces of fixed electrical equipment like ly to become energ ized that are subject to personal contact, operating at over 100 volts Metal faceplates, by means of a metal mounting screw(s) securing the face plate to a metal yoke or strap of a receptacle or to a metal outlet box

Exception No. 1: For other than isolated ground receptacles, an insulated equipment bonding jumper that directly connecl5 to the equipment grounding conductor is permitted to connect the box and receptacl.e(s) to the equipment grounding conductor. Isolated ground receptacles shall be connected in accordance with 517.16. Exception No. 2: Luminaires more than 2.3 m (7 1/i ft) above the floor and switches located outside of the patient care vicinity shall be permitted to be connected to an equipment grounding return path complying with 517.13(A) or (B).

(2) Sizing- Equipment grounding conductors and equipment bonding jumpers shal l be sized in accordance with 250.1 22. 517.14 Panelboard Bonding. The equipment grounding terminal buses of t11e no1·mal and essential branch-circuit panelboards serving the same ind ividual patient care vicinity shall b e connected together with an insulated continuous coppe1· conductor n ot sma lle 1· than 10 AWG. Where two or more panelboards serving the same individual patient care vicinity are served fro m separate transfer switches on the essent ia l elecu·ical system, the equipme nt grounding terminal buses of those panelboards sha ll be connected together with a n insulated continuous copper conductor not smaller than 10 AV•lG. This conductor shall be permitted to be broken in o rder to terminate on the equipment grounding terminal bus in each panelboard. 517.16 Use of Isolated Ground Receptacles- An isolated ground receptacle, if used, sha ll not defeat the purposes of the safety features of the grounding systems detailed in 517.13. [99:6.3.2.2.5(A)]

517.12 Wiring Methods. Except as modified in this article, wiring methods shall comply with Cha pters 1 through 4 of this Code.

(A) Inside of a Patient Care Vicinity. An isolated ground receptacle shall not be installed within a patient care vicinity. r99:6. 3.2.2.5(B)]

517.13 Equipment Grounding Conductor for Receptacles and Fixed Electrical Equipment in Patient Care Spaces. Wiring in patient care spaces shall comply with 517.1 3(A) and (B) .

(B) Outside of a Patient Care Vicinity. Isolated ground receptacle(s) installed in patient care spaces outside ofa patient care vicini ty(s) shal l comply with 5 17.1 6( B) (1) and (B) (2) .

(A) Wiring Methods. All branch ci1·cuits serving patient care spaces shall be provided with an effective ground-fault current path by installation in a metal raceway syste m or a cable having a metallic armo1· or sheath assembly. Th e metal raceway system, metallic cable armor, or sheath assembly sha ll itself qualify as an equipment grounding conductor in accordance with 250.118 .

(1) The equipment grow1ding termina ls of isolated ground receptacles installed in b ranch circui ts for patient care spaces shall be connected to an insulated equip m ent grounding conductor in accordance with 250.146(0) installed in a wiri ng method described in 517.1 3(A) .

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The equipment grow1ding conductor connected to the equipment grounding termina ls of isolated ground receptacles

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ARTICLE 517 - HEALTH CARE FACILITIES

in patient care spaces shall be clearly identified along the equipment grounding conductor's entire length by green insulation with one or more yellow stripes. (2) The insulated equipment grounding conductor required

in 517.13(B)(l) shall be clearly identified along its entire length by green insulation, with no yellow stripes, and shall not be connected to the grounding terminals of isolated equipment ground receptacles but shall be connected to the box or enclosure indicated in 517.13(B)(l)(2) and to non-currentcarrying conductive surfaces of fixed e lectrical equipment indicated in 517.13(B) (1) (3) . Informational Note No. 1: This type of installation is typically used where a reduction of electrical noise (electromagnetic interference) is necessary, and parallel grounding paths are to be avoided. Informational Note No. 2: Care shou ld be taken in specifying a system containing isolated ground receptacles, because the impedance of the effective ground-fault current path is dependent upon 1he equipment grounding conduc!Or(s) and does not benefit from any conduit or building structure in parallel with the equipment grounding conductor.

517.17 Ground-Fault Protection of Equipment. (A) Applicability. The requirements of 517 .1 7 shall apply to buildings or portions of buildings containing health care facilities with Category 1 (critical care) spaces or utilizing electrical life-support equipment, and buildings that provide the required essential utilities or services for the operation of Category 1 (critical care) spaces or electrical Life-support equipment. (B) Feeders. Where ground"fault protection of equipment is provided for operation of the service disconnecting means or feeder disconnecting means as specified by 230.95 or 215.1 0, an additional step of ground-fault protection shall be provided in all next level feeder disconnecting means downstream toward the load. Such protection shall consist of overcurrent devices and current transformers or other protective equipment that shall cause the feeder disconnecting means to open .

The additional levels of ground-fault protection of equipment shall not be installed on the load side of an essential electrical system transfer switch . (C) Selectivity. Ground-fault protection of equipment for operation of the se1vice and feeder disconnecting means shall be fully selective such that the feeder device, but not the service device, shall open on ground faults on the load side of the feeder device . Separation of ground"fault protection timecurrent characteristics shall conform to manufacturer's recommendations and shall consider all required tolerances and disconnect operating time to achieve 100 percent selectivity. Informational Note: See 230.95, Informational Note, for transfer of alternate source where ground-faul t protection is applied.

(D) Testing. When ground-fault protection of equipment is first installed, each level shall be performance tested to ensure compliance with 517.1 7(C) . This testing shall be conducted by a qualified person(s) using a test process in accordance with the instruction provided with the equipment. A written record of this testing shall be made and shall be available to the authority having jurisdiction.

517.18 Category 2 (General Care) Spaces. (A) Patient Bed Location. Each patient bed location shall be supplied by at least two branch circuits, one from the critical branch and one from the normal system. All branc h c ircuit5 from d1e normal system shall originate in the same panelboa1·d. The electrical receptacles or the cover plate for d1e e lectrical receptacles supplied from the critical bra nch shall have a distinctive color or marking so as to be readily identifiable and shall also indicate the panelboard and branch-circuit number supplying them.

Branch circuits servi ng patient bed locations shall not be part of a multiwire branch circuit. Exception No. 1: Branch circuits serving only special pmpose outlets or recef1tacles, such as portabf£ X-ray millets, shall not be required to be served from the same distribution panel or panels. Exception No. 2: The requiremenL5 of 517.1 B(A) shall not apply to patient bed locations in clinics, medical and dental offices, and outpatient facilities; psychiatric, substance abuse, and rehabilitation hospitals; sleeping rooms of nursing homes; and limited care facilities meeting the requirements of517. JO(B)(2). Exception No. 3: A Category 2 (general care) patient bed l.ocation served from two separate transfer switches on the critical branch shall not be required to have circuits from the normal system. Exception No. 4: Circuits served by Type 2 essential electrical systems shall be permitted to be fed by the equipment fJranch of the essential electriatl system. (B) Patient Bed Location Receptacles.

(1) Minimum Number and Supply. Each patient bed location shall be provided with a minimum of eight receptacles. (2) Receptacle Requirements. The receptacles required in 517.lS(B)(l) shall be permitted to be of d1e single, duplex, or quadruplex type or any combination of the three. All 1-eceptacles shal l be Listed "hospital g rade" and sha ll be so identified. The grounding terminal of each receptacle shall be connected to an insulated copper equipmen t grounding conductor sized in accordance with Table 250.1 22. Exception No. 1: The requirements of 517.IB(B)(l) and (B)(2) shall not apply to psychiatric, substance abuse, and rehabilitation hospitaL5 meeting the requirements of517. JO(B)(2). Exception No. 2: Psychiatric security romns shall not be required to have receptacf£ outleL5 installed in the room. Informational Note: It is not intended that there be a total, immediate replacement of existing non-hospital grade receptacles. It is intended, however, that non-hospital grade receptacles be replaced with hospital grade receptacles upon modification of use, renovation, or as existing receptacles need replacement.

(C) Designated Category 2 (General Care) Pediatric Locations. Receptacles that are located within patient rooms, bathrooms, playrooms, and activity rooms of pediatric units or spaces with similar risk as determined by the health care facility's governing body by conducting a risk assessment, other than infant nurseries, shall be listed and identified as "tamper-resistant" o r shall employ a listed tamper-resistant cover. f99: 6.3.2.2. l (D ) l

517.19 Category 1 (Critical Care) Spaces. (A) Patient Bed Location Branch Circuits. Each patient bed location shall be supplied by at least two branch circuits, one or

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ARTICLE 51 7 - HEALTH CARE FAGILITIES

517.20

more from the critical branch and one or more circuits from the normal system. At least one branch circuit from the critical branch shall supply an outlet(s) only at that bed location.

patient equipment grou nding point. The bonding conductor shall be permitted to be an-anged cenu·ically or looped as convenient.

The electrical receptacles or the cover plates for the electrical receptacles supplied from the life safety and critical branches shall have a d istinctive color or marking so as to be readily identifiable. [ 99:6 .7 .2 .3 .5(B)]

I nformational Nore: Where there is no patient equipment grounding poim, it is imponam that the distance between the reference grounding point and the patient care vicinity be as shon as possible to minimize any potential differences.

All branch circuits from the normal system shall be from a single panelboard. Critical branch receptacles shall be identified and shal l also indicate the panelboard and circuit number supplying them . The branch circuit serving patient bed locations shall not be part of a multiwire branch circuit. Exception No. 1: Branch circuits serving only special-purpose receptacles m· equipment in Categmy 1 (critical care) spaces shall he permitted to he served by other panelboards.

(E) Equipment Grounding and Bonding. Where a grounded electrical disU·ibution syste m is u sed and metal feeder raceway or Type MC or MI cable that qualifies as an equipment grounding conductor in accordance with 250.11 8 is installed, grounding of enclosures and equipment, su ch as panelboards, switchboards, and switchgear, shall be ensured by one of the follow ing bonding means at each termination or junction point of the metal raceway or Type MC m MI cable:

(1)

Exception No. 2: Category 1 (critical care) spaces served from two separate critical /Jranch transfer switches shall not he required to have circuits from the normal system.

(2)

(B) Patient Bed Location Receptacles.

(3)

(1) Minimum Number and Supply. Each patient bed location shall be provided with a minimum of 14 receptacles, at least one of which shall be connected to either of the following: (1) (2)

The normal system branch circuit required in 517.1 9(A) A critical branch circuit supplied by a different transfer switch tl1an the other receptacles at the same patient bed location

(2) Receptacle Requirements. The receptacles 1·equired in 517. l 9(B) (1) shall be permitted to be single, duplex, or quadrnplex type or any combination thereof. All receptacles shall be listed "hospital grade" and shall be so identified. The grounding terminal of each receptacle shall be connected to the reference grounding point by means of an insulated copper equipment grounding conductor. (C) Operating Room Receptacles.

(1) Minimum Number and Supply. Each operating room shall be provided with a minimum of 36 receptacles divided between at lea.st two branch c ircuits. At lea.st 12 receptacles, but no more than 24, shall be connected to either of the following: (1) (2)

The normal system branch circuit required in 517.1 9(A) A critical branch circuit supplied by a different transfer switch than the other receptacles at the same location

(2) Receptacle Requirements. The receptacles shall be permitted to be of the locking or non locking type, single, duplex, or quadruplex types or any combination of the three. All nonlocking-type receptacles shall be listed hospital grade and so identified. The grounding terminal of each receptacle shall be connected to the reference grounding point by means of an insulated copper equipment grounding conductor. (D) Patient Care Vicinity Grounding and Bonding (Optional). A patient care vicinity shall be pennitted to have a patient equipment grounding point. The patient equipment grounding point, where supplied, shall be permitted to contain one or more listed grounding and bonding jacks. An equipment bonding jumper not smaller than 10 AWG shall be u sed to connect the grounding terminal of all grounding-type receptacles to the

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NATIONAL ELECTRICAL CODE

A grounding bushing and a continuous copper bonding jumper, sized in accordance with 250.122, with the bonding jumper connected to the junction e nclosure or the ground bus of the panel Connection offeeder raceways or Type MC 01· MI cable to threaded hubs or bosses on terminating enclosures Other approved devices su ch as bonding-ty pe locknut..~ or bush ings. Standard locknuts shall not be used fo1· bonding.

(F) Additional Protective Techniques in Category 1 (Critical

Care) Spaces (Optional). Isolated power systems shall be permitted to be u sed for Category 1 (critical care) spaces, and, if used, the isolated power system equipment shall be listed as isolated power equipment. The isolated power system shall be designed and installed in accordance with 5 17.160. Exception: The audible and visual indicatm·s of the line isolation monitor shall be permitted to he located at the nursing station for the area being served.

(G) Isolated Power System Equipment Grounding. Where an isolated ungrounded power source is used and limits the firstfault current to a low magnitude, the equipment grounding conductor associated with the secondary circuit shall be penn.itted to be run outside of the enclosure of the power conductors in the same circuit. Informational Nore: Although it is permined to run the equipmem grounding conductor outside of the conduit, it is safer to run it with the power conductors to provide better protection in case ofa second ground fault.

(H) Special-Purpose Receptacle Grounding. The equipment grounding conductor fo1· s pec ial-purpose 1·eceptacles, such as the operation of mobile X-ray equipment, shall be extended to the reference grounding poin ts of b ranch circuits for all locations likely to be senred from such receptacles. '.\'here such a circuit is served from an isolated ungrounded system , the equipment grounding conductor shall not be required to be run with the power conductors; however, the equipment grounding terminal of the specia l-purpose receptacle shall be connected to the reference grounding point. 517.20 Wet Procedure Locations. (A) Receptacles and Fixed Equipment. Wet procedure locations shall be provided with special protection against electric shock. [99:6.3.2.3.1 l This special protection shal l be provided as follows:

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ARTICLE 517 - HEALTH CARE FACILITIES

Power distribution syste m that inherently limits the possible ground-fault current due to a first fault to a low value, without interrupting the power supply (2) Power distribution system in which the power supply is interrupted if the ground-fault current does, in fact, exceed tl1e trip value of a Class A GFCI. (99:6.3.2.3.2]

(1)

l'.xception: Branch circuits supplying only listed, fixed, therapeutic and diagnostic equipment shall be perrnitted to be supplied from a grounded service, single- or 3-phase system, provided that (1) (2)

Informational Note No. l: For additional information, see NFPA l 10-2019, Standard for Emergency and Standby Power Sys/Jims. I nformational Note No. 2: For additional information, see 517.29 and NFPA 99-2018, Health Care Facilities Code.

517.29 Type I Essential Electrical Systems. Informational Note: Type l essential electrical systems are comprised of tl1ree separate branches capable of supplying a limited amount of lighting and power service that is considered essential for life safety and effective facility operation during the time the normal electrical service is interrupted for any rea~on. These tl1ree separate branches are the life safety, critical, and equipment brai1ches. [99:A.6.7.2.3)

Wiring for grounded and isol.ated circuits does not occupy the same raceway, and All conductive sU?faces of the equipment are connected to an insulated copper equipment grounding conduct01:

(B) Isolated Power Systems. v\There an isolated power system is utilized, the isolated power equipment shall be listed as isolated power equipment, and the isolated power system shall be designed and installed in accordance with 517.160. Informational Note: For requiremenL~ for instal lation of therapeutic pools and nibs, see Pan VI of Article 680.

517.21 Ground-Fault Circuit-Interrupter Protection for Personnel in Category 2 (General Care) and Category I (Critical Care) Spaces. Receptacles shall not be required in bathrooms or toilet rooms. [99:6.3.2.2.2(D)] Receptacles located in patient bathrooms and toilet rooms in Category 2 (general care) spaces shall have ground-fault circuit-interrupter protection in accordance with 210.S(B) ( 1) . Ground-fault circuit-interrupter protection for personnel shall not be required for receptacles installed in those Category 2 (general care) and Category 1 (critical ca1-e) spaces where a basin, sink, or other similar plumbing fixture is installed in the patient bed location. Informational Note: For information on the supply connection of life-support equipment to circuits providing ground-fault circuit-interrupter (GFCI) protection of personnel at outlets, see ANSI/ UL 943-20 18, Ground-Fault Cirettil-lnlernt/Jlers, Annex E, and, in accordance with 110.3(B) , the manufacturers' installation instructions of listed ground-fault circuit interrupters.

Part III. E.ssential Electrical System (EES)

517.25 E.ssential Electrical Systems for Health Care Facilities. Type 1 and Type 2 essential elecu-ical systems (EES) for health care facilities shall com prise separate branches capable of supplying a limited amount of lighting and power service, wh ich is considered essential for life safety and orderly cessation of procedures during the time normal electrical service is interrupted for any reason. Informational Note: For information on tl1e need for an essential electrical system, see NFPA 99-2018, Heallh Care Facilities Code.

517.26 Application of Other Articles. The life safety branch of the essential electrical system shall meet the requirements of Article 700, except as amended by Article 517. (1) (2) (3)

( 4)

Section 700.4 shall not apply. Section 700.lO(D) shall not apply. Section 700 .17 shall be replaced with the following: Branch circ uits that supply emergency lighting shall be installed to provide service from a source complying with 700.1 2 when normal supply for lighting is interrupted or

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where single circuits supply luminaires containing secondary batteries. Section 700.32 shall not apply.

(A) Applicability. The requirements of Part III, 517.29 tl1rough 517.35, shall apply to Type 1 essential electrical systems. Type 1 systems shall be required fo1· Category 1 (critical care) spaces. Type 1 systems shall be permitted to serve Category 2 (general care), Category 3 (basic care), and Category 4 (support) spaces. Informational Note No. l: For performance, maintenance, and testing requirements of essential electrical systems in hospitals, see NFPA 99-2018, Health Care Facilities Code. For installation of centrifugal fire pumps, see NFPA 20-2019, Standard for lhe Inslallalion of Slalionmy Pttmps for Fire Protection.

Informational Note No. 2: For additional information on Type l and Type 2 essential electrical systems, see NFPA 99-2018, Health Cm-eFacilities Code, 6.7.5 and 6.7.6.

(B) Type I E.ssential Electrical Systems. Category 1 (critical

care) spaces shall be se rved by a Type 1 essential e lectrical syste1n. [99:6.4.1] Category 1 spaces shall not be served by a Type 2 EES. [99:6.4.21 517.30 Sources of Power. (A) Two Independent Power Sources. Essential electrical systems shall have a minimum of the following two independent sources of power: a normal source generally supplying the entire electrical system and one or more alternate sources for use when the normal somce is interrupted . (99:6.7.1.2.2] (B) Types of Power Sources.

(1) Generating Units. \0rary wiring. All cords or cables shall be install.ed in a single laye1: A permanent sign shall be attached to the cable tray at intervals not to exceed 7.5 m (25 ft). The sign shall read CABLE TRAY FOR TEMPORARY WIRING ONLY (C) Emergency Systems. Control of emergen cy systems shall comply with Ai-tide 700.

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ARTICLE 520 -THEATERS, MOTION PICTURE & TELEVISION STUDIOS, & SIMILAR LOCATIONS 518.4 Wiring Methods. (A) General. The fixed wiring methods shall be metal raceways, flexible metal raceways, nonmetallic raceways encased in not less than 50 mm (2 in.) of concrete, Type MI, MC, or AC cable. The wiring method shall itself qualify as an equipment grounding conductor according to 250.11 8 or shall contain an equipment grounding conductor sized in accordance with Table 250.122. Exception: Fixed wiring methods shall be as provided in the following: ( 1)

Audio signal processing, amplification, and reproduction equipment - Article 640 Communications systems - Chapter 8 Class 2 and Class 3 remote-control and signaling circuits Article 725 Fire alarm circuits - Article 760

(2) (3) (4)

(B) Nonrated Construction. In addition to the wiring methods of 518.4(A), nonmetallic-sheathed cable, electrical nonmetallic tubing, and rigid nonmetallic conduit shall be permitted to be installed in those buildings or portions thereof that a1·e not required to be of fire-rated construction by the applicable building code. Informational Nore: Fire-rared consrruction is the fire-resistive classification used in building codes.

(C) Spaces with Finish Rating. Electrical norunetallic tubing and rigid nonmetallic conduit shall be permitted to be installed in club rooms, conference and meeting rooms in hotels or motels, couru·ooms, dining facilities, restatmmts, mortuary chapels, museums, libraries, and places of religious worship where the following apply:

(1)

(2)

The elecu-ical nonmetallic tubing or rigid nonmetallic conduit is installed concealed within walls, floors, and ce ilings where the walls, floo1·s, and ceilings provide a thermal barrier of material that has at least a l !:>-minute finish rating as identified in listings of fire-rated assemblies. The elecu·ical nonmetallic tubing or rigid nonmetallic conduit is installed above suspended ceilings where the suspended ceilings provide a thermal barrier of material that has at least a 1!:>-minute finish rating as identified in listings of fire-rated assemblies.

Electrical nonmetallic tubing and rigid nonmetallic conduit are not recognized for use in other space used for environmental air in accordance with 300.22(C) . Informational Note: A finish rating is established for assemblies containing combustible (wood) supports. The finish rating is defined as the time at which the wood stud or wood joist reaches an average temperature rise of 121 °C (250°F) or an individual temperature rise of 163°C (325°F) as measured on the plane of the wood nearest the fire. A finish rating is not intended to represent a rating for a membrane ceiling.

518.5 Supply. Portable switchboards and portable power disu·ibution equipment shall be supplied only from listed power outlets of sufficient voltage and ampere rnting. Such power outlets shall be protected b y overcurrent devices. Such overcurrent devices and power outlets shall not be accessible to the general public. Provisions for connection of an equipment grounding conductor shall be provided. The netmal conductor of feeders supplying solid-state phase conu·ol, 3-phase, 4-wire dimmer systems shall be conside1·ed a current-carrying conductor for purposes of ampacity adjustment. The neutral conduc-

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520.2

tor of feeders supplying solid-state sine wave, 3-phase, 4-wire dimming systems shall not be considered a current-carrying conductor for purposes of ampacity adjustment. Exception: The neutral conductor offeeders supplying systems that use or are capable of using both phase-control and sine-wave dimmers shall be considered as current-canying for purposes of ampacity adjustment. Informational Nore: For definitions of solid-state dimmer types, see 520.2.

518.6 Illumination. Illumination shall be provided for all working spaces about fixed service equipment, switchboa1·ds, switchgear, panelboards, or motor control centers installed outdoors that serve assembly occupancies. Conu-ol by automatic means only shall not be permitted. Additional lig hting outlets shall not be requi red where tl1e workspace is illuminated by an adjacent light source .

ARTICLE520 Theaters, Audience Areas of Motion Picture and Television Studios, Performance Areas, and Similar Locations Part I. General 520.1 Scope. This article covers all buildings or that part of a building or su·ucture, i ndoor or outdoor, designed or u sed fo r presentation, dramatic, musical, motion picture projection, or similar purposes and to specific audience seating areas within motion picture or television studios. 520.2 Definitions. The definitions in this section shall apply only with in this article. Adapter. A device used to adapt a circuit from one configuration of an attachment plug or receptacle to another configuration with the same current rating. Border Light. A permanently installed overhead strip Light. Breakout Assembly. An adapter used to connect a multipole connector containing two or more branch circuits to multiple individual branch-circuit connectors. Bundled. Cables or conductors that are tied, wrapped, taped, or otherwise periodically bound together. Connector Strip. A metal wireway containing pendant or flush receptacles. Drop Box. A box containing pendant- or flush-mounted receptacles attached to a multiconducto1· cable via strain relief or a multi pole connector. Footlight. A border light installed on or in the stage . Grouped. Cables or conductors positioned adjacent to one another but not in conti nuous contact with each other. Performance Area. The stage and audience seating a rea associated with a temporaqr stage structure, wh etl1e1· indoors or outdoors, constructed of scaffolding, u-uss, platforms, or similar devices, that is used for the presentation of theau-ical or musical productions or for public presentations.

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520.3

ARTICLE 520 -THEATERS, MOTION PICTURE & TELEVISION STUDIOS, & SIMILAR LOCATIONS

Portable Equipment. Equipment fed with portable cords or cables intended to be moved from one place to another. Portable Power Distribution Unit. A power distribution box containing receptacles and overcurrent devices. Proscenium. The wall and arch that separates the stage from the auditorium (house). Solid-State Phase-Control Dimmer. A solid-state dimmer where the wave shape of the steady-state cun-ent does not follow the wave shape of the applied voltage, such that the wave shape is nonlinear. Solid-State Sine Wave Dimmer. A solid-state dimmer whe1-e the \\lave shape of the steady-state current follows the wave shape of the applied voltage such that the \\lave shape is linear. Stage Equipment. Equipment at any location on the premises integral to the stage production including, but not limited to, equipment for lighting, audio, special effects, rigging, motion control, projection, or video. Stage Lighting Hoist. A motorized lifting device that contains a mounting position for one or more luminaires, with wiring devices for connection of luminaires to branch circuits, and integral flexible cables to allow the luminaires to travel over the lifting range of the hoist while energized. Stage Switchboard. A permanently installed switchboard, panelboard, or rack containing dimmers or relays with associated overcurrent protective devices, or overcurrent protective devices alone, used primarily to feed stage equipment. Stage Switchboard, Portable. A portable rack or pack containing dimmers or relays with associated overcurrent protective devices, or overcurrent protective devices alone that are used to feed stage equipment. Stand Lamp (Work Light). A portable stand that contains a general-purpose luminaire or lampholder with guard for the purpose of providing general Lllumination on the stage or in the auditorium . Strip Light. A luminaire with multiple lamps arranged in a row. Two-Fer. An assembly containing one male plug and t\vo female cord connectors used to connect two loads to one branch circuit. 520.3 Motion Picture Projectors. Motion picture equipment and its installation and use shall comply with Article 540. 520.4 Audio Signal Processing, Amplification, and Reproduction Equipment. Audio signal processing, amplification, and reproduction equipment and its installation shall comply with Article 640 .

(B) Portable Equipment. The wi ring for portable switchboards, stage set lighting, stage effects, and other wiring not fixed as to location shall be permitted with approved flexible cords and cables as provided elsewhere in Article 520. Fastening such cables and cords by uninsulated staples or nailing shall not be permitted. (C) Nonrated Construction. Nonmetallic-sheathed cable, Type AC cable, electrical nonmetallic u1bing, and rigid nonmetalli c conduit shall be permitted to be installed in those buildings or portions thereof that are not required to be of fire-rated construction by the applicable building code.

520.6 Number of Conductors in Raceway. The number of conductors permitted in any metal conduit, rigid nonmetallic conduit as permitted in this article, or electrical metallic u1bing for circuits or for remote-control conductors shall not exceed tl1e percentage fill shown in Table 1 of Chapter 9. Where contained within an auxiliat')' gutter or a wire\\lay, the sum of t11e cross-sectional areas of a ll contained conductors at any cross section shall not exceed 20 percent of the interior crosssectional area of the auxiliat')' gutter or wi1-e\\lay. The 30conductor limitation of 366.22 and 376.22 shall not apply. 520. 7 Enclosing and Guarding Live Parts. Live part5 shall be enclosed or guarded to prevent accidental contact by persons and o bjects. AJl switches shall be of tl1e externally operable LJ'Pe. Dimmers, including rheostat5, shall be placed in cases or cabinets that enclose all live parts. 520.8 Emergency Systems. Control of emergency systems shall comply with Article 700. 520.9 Branch Circuits. A branch circuit of any size supplying one or more receptacles shall be permitted to supply stage set lighting. The voltage rating of t11e receptacles shall be not less than the circuit voltage. Re ceptacle ampere ratings and branchcircuit conductor ampaciLy shall be not less than the branchcircuit overcurrent device ampere rating. Table 210.21 (B) (2) and 210.23 shall not apply. The requirements in 210.S(B) , ot11er tl1a.11 210.8(B)(4), shall apply. 520.10 Portable Equipment Used Outdoors. Portable stage and studio lighting equipment a nd portable power d isu-ibution equipment not identified for outdoor use shal l be permitted for temporary use outdoors, provided the equipment is supervised by qualified personnel while e nergized and ban-iered from the general public.

Part II. Fixed Stage Switchboards 520.21 General. Fixed stage switchboards shall comply with 520.21(1) tluough (4): (1)

520.5 Wiring Methods. (A) General. The fixed wiring method shall be metal raceways, nonmetallic race\\laYS encased in at least 50 mm (2 in.) of concrete, Type MI cable, MC cable, or AC cable containing an insulated equipment grounding conductor sized in accordance with Table 250.122. Exception: Fixed wiring methods shall he as provided in Article 640 for audio signal processing, amplification, and reproduction equipment, in Article 805 for communications circuits, in Article 725 for Class 2 and Class 3 remote-control and signaling circuits, and in Article 760 for fire alarm circuits.

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(2)

(3)

( 4)

Fixed stage s\vitchboards shall be listed. Fixed stage switchboards shall be readily accessible but shall not be required to be located on or adjacent to t11e stage . Multiple fixed stage switchboards shall be permitted at different locations. A fixed stage S\vitchboard shall con tain overcurrent protective devices for all branch circuits supplied b y tl1at S\vi tch board. A fixed stage S\vitchboard shall be permitted to supply bot11 stage and non-stage equipment.

520.25 Dimmers. Dimmers through (C) .

shall

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520.25(A)

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520.42

ARTICLE 520 -THEATERS, MOTION PICTURE & TELEVISION STUDIOS, & SIMILAR LOCATIONS (A) Disconnection and Overcurrent Protection. Where dimme1-s are installed in ungrow1ded conducto1-s, each dimmer shall have overcurrent protection not greater than 125 percent of the dimmer rating and shall be disconnected from all ungrounded conductors when the master or individual switch or circuit breaker supplying such dimmer is in the open position . (B) Autotransformer-Type Dimmers. The circuit supplying an autotransformer-type dimmer shall not exceed 150 volts between conductors. The grounded conductor shall be common to the input and output circuits. Informational Note: See 210.9 for circuits derived from autotransformers.

(C) Solid-State-Type Dimmers. The circuit supplying a solidstate dimmer shall not exceed 150 volts between conductors unless the dimmer is listed specifically for higher voltage operation . Where a grounded conductor supplies a dimmer, it shall be common to the input and output circuits. Dimmer chassis shall be connected to the equipment grounding conductor.

520.26 Type of Switchboard. A stage switchboard shall be either one or a combination of the types specified in 520.26(A), (B), (C),and (D) . (A) Manual. Dimmers and switches are operated by handles mechanically linked to the control devices.

(B) Remotely Controlled. Devices are operated electrically from a pilot-type conu-ol console or panel. Pilot control panels either shall be part of the switchboard or shal l be permitted to be at another location. (C) Interme diate. A stage switchboard with circuit interconnections is a secondary svvitchboard (patch panel) or panelboard remote to the primary stage switchboard. It shall contain overcurrent protection. 'i\There the required branch-circuit overcurrent protection is provided in the dimmer panel, it shall be permitted to be omitted from the intermediate switchboard.

(D) Constant Power. A stage switchboard containing only overcurrent protective devices and no control e lements. 520.27 Stage Switchboard Feeders. (A) Type of Feeder. Feeders supplying stage switchboards shall be one of the types in 520.27(A)(l) through (A)(3) . (I) Single Feeder. A single feeder disconnected by a single disconnect device. (2) Multiple Feeders to Intermediate Stage Switchboard (Patch Panel). Multiple feeders of unlimited quantity shall be permitted, provided that all multiple feeders are part of a single system. Where combined, neutral conductors in a given race\vay shall be of sufficient ampacity to carry the maximum unbalanced current supplied by multiple feeder conductors in the same raceway, but they need not be greater than the ampacity of the neutral conductor supplying the primary stage switchboard. Parallel neutral conductors shall comply with 3 10.l O(G) . (3) Separate Feeders to Single Primary Stage Switchboard (Dimmer Bank). Instal lations with separate feeders to a single primary stage switchboard shall have a disconnecting means for each feeder. The primary stage switchboard shall have a permanent and obvious label stating the number and location of

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disconnecting means. If the d isconnecting means are located in more than one d isu-ibution switc hboard, the primary stage switchboard shall be provided with barriers to correspond with these multiple locations. (B) Neutral Conductor. For the purpose of ampacity adjustment, the following shall apply:

(1)

(2)

(3)

The neutral conductor of feeders supplying solid-state, phase-control 3-phase, 4-wire dimming syste ms shall be considered a c urrent-carrying conductor. The neutral conductm- of feeders supplying solid-state, sine \vave 3-phase, 4-wire dimming systems shall not be considered a current-carrying conductor. The neutral conductor of feeders supplying systems that use or are capable of using both phase-control and sine \vave dimmers shall be considered as current-carrying.

(C) Supply Capacity. For the purposes of calculating supply capacity to switchboards, it shall be permissible to consider the maximum load that the switchboard is intended to control in a given installation, provided that the following apply:

(1)

(2)

All feeders supplying the switchboard shall be protected by an overcurrent device with a rating not greater than the ampacity of the feeder. The opening of the overcurrent device shall not affect the proper operation of the eg1-ess or emergency lig hting systems. Informational Note: For calculation of stage switchboard feeder loads, see 220.40.

Part III. Fixed Stage Equipment Other Than Switchboards 520.40 Stage Lighting Hoists. Where a stage lighting hoist is listed as a complete assembly and contains an integral cablehandling syste m and cable to connect a moving wiring device to a fixed junction box for connection to permanent wiring, the exu-a-hard usage 1-equirement of 520.44(C) (1) shall not apply. 520.41 Circuit Loads. (A) Circuits Rated 20 Amperes or Less. Footlights, bo1-der lights, and proscenium sidelights shall be arranged so that no branch circuit supplying such equipment carries a load exceeding 20 amperes. (B) Circuits Rated Greater Than 20 Amperes. v\There only heavy-duty lampholders are used, such circuits shall be permitted to comply with Article 210 for c ircuits supplying heavy-duty lampholders.

520.42 Conductor Insulation. Foot, border, proscenium, or portable su-ip Lights and connector strips shall be wired with conductors that have insulation suitable for the temperature at which the conductors are operated, but not less than 125°C (257°F). The ampacity of the 125 °C (257°F) conductors sha ll be that of 60°C (14Q°F) conductors. All drops from connector su-ips shall be 90°C (194°F) wire sized to the ampacity of 60°C (140°F) cords and cables wit11 no more than 150 mm (6 in.) of conductor extending into the connector strip. Section 310.1 5(C) (1) shall not apply. Informational Note: See Table 310.4(A) for conductor types.

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520.43

ARTICLE 520 - THEATERS, MOTION PICTURE & TELEVISION STUDIOS, & SIMILAR LOCATIONS

520.43 Footlights. (A) Metal Trough Construction. Whe1-e metal trough construction is employed for footlights, the u-ough containing the circuit conductors shall be made of sheet metal not lighter than 0.81 mm (0.032 in.) and treated to prevent oxidation. Lampholder terminals shall be kept at least 13 mm (Y; in. ) from the metal of the trough . The circuit conductors shall be soldered to the lampholder terminals. (B) Other-Than-Metal Trough Construction. \'\There the metal trough construction specified in 520.43(A) is not used, footlights shall consist of individual outlets with lampholders wired with rigid metal conduit, intermediate metal conduit, or flexible metal conduit, Type MC cable, or mineral-insulated, metalsheathed cable . The c ircuit conductors shall be soldered to the lampholder terminals. (C) Disappearing Footlights. Disappea1-ing footlight5 shall be arranged so that the current supply is automatically disconnected when the footlights are replaced in the storage recesses designed for them.

520.44 Borders, Proscenium Sidelights, Drop Boxes, and Connector Strips. (A) General. Borders and proscenium sidelights shall be as follows: (1) (2) (3)

Constructed as specified in 520.43 Suitably stayed and supported Designed so that the flanges of the reflectors or other guards protect the lamps from mechanical damage and from accidental contact with scenery or other combustible material

(B) Connector Strips and Drop Boxes. Connector strips and drop boxes shall be as follows: ( 1) (2)

Suitably stayed and supported Listed as stage and studio wiring devices

(C) Cords and Cables for Border Lights, Drop Boxes, and Connector Strips.

(1) General. Cords and cables for supply to border lights, drop boxes, and connector strips shall be listed for extra-hard usage. The cords and cables shall be suitably supported. Such cords and cables shal l be employed only where flexible conductors are necessary. Ampaci ty of the conductors shall be as provided in 400.5. (2) Cords and Cables Not in Contact with Heat-Producing Equipment. Listed multiconductor extra-hard-usage-type cords and cables not in direct contact with equipment containing heat-producing e lements shall be permitted to have their ampacity determined by Table 520.44(C)(2) . Maximum load current in any conducto1- with an ampacity determined by Table 520.44(C) (2) shall not exceed the values in Table 520.44(C) (2) .

Table 520.44(C)(2) Ampacity of Listed Extra-Hard-Usage Cords and Cables with Temperature Ratings of 75°C (l67°F) and 90°C (194°F) [Based on Ambient Temperature of 30°C (86°F)] Temperature Rating of Cords and Cables Size (AWG)

75°c (l67°F)

90°C (194°F)

Maximum Rating of Overcurrent Device

24 32 41 57 77 IOI 133

28 35 47 65 87 ll4 152

15 20 25 35 45 60 80

14 12 10 8 6 4 2

Note: Ampacity shown is the ampacity for multiconductor cords and cables where only three copper conductors are current-carrying as described in 400.5. If d1e number of current-carrying conductors in a cord or cable exceeds three and the load diversity is 50 percent or less, d1e ampacity of each conductor shall be reduced as shown in the following table:

Table 520.44(C)(3) Ampacity Adjustment Factors for More Than Three Current-Carrying Conductors in a Cord or Cable Where Load Diversity Is 50 Percent or Less

Number of Conductors

4-6 7-24 25-42 43 and above

Percent of Ampacity Value in Table 520.44(C)(3) 80 70 60 50

Note: Ultimate insulation temperature. ln no case shall conductors be associated toged1er in such a way wid1 respect to the kind of circuit, the wiring med1ocl used, or the mm1ber of conductors such that d1e temperature limit of d1e conductors is exceeded. A neuu·al conductor that carries only the unbalanced cu rrent from od1er conductors of d1e same circuit need not be considered as a current-carrying conductor. In a 3-wire circuit co nsisting of two-phase conductors and the neutral conductor of a 4-wire, 3-phase, wye-connected system, the neutral conductor carries approximately d1e same current as the line-to-neutral cw-rents of the od1er conductors and shall be considered to be a current-carrying conductor. On a 4-wire, 3-phase wye circuit where the major portion of the load consists of nonlinear loads, there are harmonic currents in t he neutral conductor. TI1erefore, the neutral conductor shall be considered to be a current-carrying conductor. Informational Note: For the purposes of Table 520.44 (C) (3), load diversity is the percentage of the total c urrent of all simultaneously energized circuits foci by the cable to d1e sum of the ampacity of all circuits in that cable.

(3) Identification of Conductors in Multiconductor ExtraHard-Usage Cords and Cables. Neuu·al conductors sha ll be white without stripe or shall be identified by a distinctive white marking at their terminations. Equipment grow1ding conductors shall be green \\Tith or \'lithout yellow su-ipe or shall be identified by a distinctive green marking at their terminations.

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ARTICLE 520 -THEATERS, MOTION PICTURE & TELEVISION STUDIOS, & SIMILAR LOCATIONS 520.45 Receptacles. Receptacles for eleca-ical equipment on stages shall be rated in amperes. Conductors supplying receptacles shall be in accordance with Articles 310 and 400. 520.46 Connector Strips, Drop Boxes, Floor Pockets, and Other Outlet Enclosures. Receptacles for the connection of portable stage-lighting equipment shall be pendant or mounted in pockets or enclosures and shall comply with 520.45. Supply cables for connector strips and drop boxes shall be as specified in 520.44(C) . 520.47 Backstage Lamps (Bare Bulbs). Lamps (bare bulbs) installed in backstage and ancillary areas where they can come in contact with scenery shall be located and guarded so as to be free from physical damage and shall provide an air space of not less than 50 mm (2 in.) between such lamps and any combustible material. l!.xception: Dewrative !,amps installed in scenery shall not be considered to be backstage lamps for the purpose of this section.

520.48 Curtain Machines. Curtain machines shall be listed. 520.49 Smoke Ventilator Control. v\There stage smoke ventilators are relea5ed by an electrical device, the circuit operating the device shall be normally closed and shall be controlled by at least t\vo externally operable switches, one switch being placed at a 1-eadily accessible location on stage and the other where designated by the authority having jurisdiction. The device shall be designed for the full voltage of the circuit to which it is connected, no resistance being inserted. The device shall be enclosed in a metal box having a door that shall remain closed except during service to the equipment.

Part IV. Portable Switchboards on Stage 520.50 Road Show Connection Panel (A Type of Patch Panel ). A panel designed to allow for road show connection of portable stage switchboards to fixed lig hting outlets by means of permanently installed supplementary circuits. The panel, supplementary circuits, and outlets shall comply with 520.50(A) through (D) . (A) Load Circuits. Ci1-cuits shall ongmate from groundingtype polarized inlets of current and voltage rating that match the fixed-load receptacle.

of ampacity adjustment, the requirements of 520.27(B) shall apply. 520.52 Overcurrent Protection for Branch Circuits. Portable switchboards shall contain overcurrent protection for branch circuits. The requirements of 210.23 shall not apply. 520.53 Construction. Portable stage switchboards shall be listed and shall comply with 520.53(A) through (E) . (A) Pilot Light. A pilot light shall be provided for each ungrounded conductor feed ing the swi tchboard. The pilot light(s) shall be connected to the in coming feeder so that operation of the main overcmTent protective device or master switch shall not affect the operation oftl'le pilot light(s) . (B) Neutral Terminal. I n portable switchboard equipment designed for use with 3-phase, 4-wire with ground supply, the current rating of the supply neutral terminal, and the ampacity of its associated busbar or wiring, or both, shall have an ampacity equal to at least twice the ampacity of the largest ungrounded supply terminal. Exception: Where portable switchboard equipment is specifically constructed and identified to be internally converted in the field, in an approved manner, from use with a balanced 3-phase, 4-wire with grmmd supply to a balanced single-phase, 3 -wire with ground supply, the supply neutral terminal and its associated lnlSbar, wiring, or both, shall have an amf1acity equal to at least that of the largest ungrounded single-phase supply terminal (C) Single-Pole Separable Connectors. 'W here single-pole portable cable connectors are used on a portable stage switchboard, tl'ley shall be listed and of the locking type. Sections 406 .7 and 406.8 shall not apply to listed si ngle-pole separable connectors and single-conductor cable assemblies utilizing listed single-pole separable connectors. v\lhere paralleled sets of current-carrying, single-pole separable connectors are provided as input devices, they shall be promin ently labeled wim a warning indicating the presence of internal parallel connections. The use of single-pole separable connectors shall comply with at least one of the fo llowing conditions:

(1)

(2)

(B) Circuit Transfer. Circuits that are transferred benveen fixed and portable switch boards shall have all circuit conductors transferred simultaneously. (C) O vercurrent Protection. The supply devices of these supplementary circuits shal l be protected by branch-circuit overcurrent protective devices. Each supplementary circuit, witl'lin the road show connection panel and theater, shall be protected by branch-circuit overcurrent protective devices installed within the road show connection panel.

(D) Enclosure. Panel construction shall be in accordance with Article 408 . 520.51 Supply. Portable switchboards shall be supplied only from power outlets of sufficient voltage and ampere rating. Such power outlets shall include only externally operable, enclosed fused switches or circuit breakers mounted on stage or at the permanent switchboard in locations readily accessible from the stage floor. Provisions for connection of an equipment grounding conductor shall be provided. For the purposes

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520.53

(3)

Connection and disconnection of connecto1-s are possible only where the supply connectors are interlocked to the source, and it is not possible to connect or disconnect connectors when the supply is energized. Line connectors are of the listed sequential-interlocking type so that load connectors shall be connected in the following sequence : a. Equipment grounding conductor connection b. Grounded c ircuit conductor conne ction, if provided c. Ungrounded conductor connection, and that disconnection shall be in the reverse order A caution notice shal l be provided adjacent to the line connectors indicating that plug connection shall be in the following order: a. Equipment groundi ng conductor connectors b. Grounded c ircuit conductor connectors, if provided c. Ungrounded conductor connectors, and that disconnection shall be in the reverse order

The warning sign (s) o r label(s) shall comply with 110.21 (B) . (D) Supply Feed-Through. Where a portable stage switchboard contains a feed-through outlet of the same rating as its supply inlet, the feed-through outlet shall not require overcurrent protection in the switchboard.

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ARTICLE 520 -THEATERS, MOTION PICTURE & TELEVISION STUDIOS, & SIMILAR LOCATIONS

(E) Interior Conductors. All conductors other than busbars within the switchboard enclosure shall be stranded.

(5)

Conductors shall be continuous \'lithout splices or connectors. Conductors shall not be bundled. Conductors shall be supported above the floor in an approved manner.

520.54 Supply Conductors.

(6) (7)

(A) General. The supply to a portable stage switchboard shall be by means of listed extra-hard usage cords or cables. The supply cords or cables shall terminate within the switchboard enclosure i.n an externally operable fused master switch or circuit b1-eaker or in an identified connector assembly. The supply cords or cable (and connector assembly) shall have current ratings not less than the total load connected to the switchboard and shall be protected by overcurrent devices.

(E) Supply Conductors Not Over 6 m (20 ft) Long. \'\'here supply conductors do not exceed 6 m (20 ft) in length between supply and S\'litch board or supply and a subsequent overcurrent protection device, the supply conductors shall be permitted to be reduced in size where all of the follm'ling conditions are met:

(B) Conductor Sizing. The power supply conductors for portable stage switchboards utilizing solid-state phase conu-ol dimme1-s shall be sized conside1-ing the neuu-al conductor as a current-carrying conductor for ampacity adjustment purposes. The power supply conductors for portable stage switchboards utilizing only solid-state sine wave dimmers shall be sized considering the neuu-al conductor as a non-current carrying conductor for ampacity adjusunent purposes. (C) Single-Conductor Cables. Single-conductor portable supply cable sets shall be not smaller than 2 AWG conductors . The equipment grounding conductor shall not be smaller than fi AWG conductor. Single-conductor grounded neuu-al cables for a supply shall be sized in accordance with 520.54(J) . Where single conductors are paralleled for increased ampacity, the paralleled conductors shall be of the same length and size. Single-conductor supply cables shall be grouped together but not bundled. The equipment grounding conductor shall be permitted to be of a different type, provided it meets the other requirements of this section, and it shall be permitted to be reduced in size as permitted by 250.1 22. Grounded (neuu-al) and equipment grounding conductors shall be identified in accordance with 200.6, 250.119, and 310.6. Grounded conductors shall be permitted to be identified by marking at least the first 150 mm (6 in. ) from both ends of each length of conductor with white or gray. Equipment grounding conductors shall be permitted to be identified by marking at least the first 150 mm (6 in.) from both ends of each length of conductor \vi th green or green \'lith yellow stripes. Where more than one nominal voltage exi.st5 within the same premises, each ungrounded conductor shall be identified by system.

(D) Supply Conductors Not Over 3 m (10 ft) Long. Where supply conductors do not exceed 3 m (10 ft) in length between supply and w.ritchboard or supply and a subsequent overcurrent device, the supply conductors shall be permitted to be reduced in size where all of the following conditions are met: (1)

(2)

(3)

(4)

The ampacity of the supply conductors shall be at least one-quarter of the current rating of the supply overcurrent protective device. The supply conductors shall terminate in a single overcurrent protective device that will limit the load to the ampacity of the supply conductors. This single ove1-current device shall be permitted to supply additional overcurrent devices on its load side. The supply conductors shall not peneu-ate walls, floors, or ceilings or be run through doors or traffic areas. The supply conductors shall be protected from physical damage. The supply conductors shall be suitably terminated in an approved manner.

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(1 ) (2)

(3)

( 4) (5)

(6) (7)

The ampacity of the supply conductors shall be at least one-half of the cmTent rating of the supply overcurrent protective device. The supply conductors shall terminate i.n a single overcurren t protective device that limits the load to the ampacity of the supply conductors. This single overcurrent device shall be permitted to supply additional overcurrent devices on its load side. The supply conductors shall not penetrate walls, floors, or ceilings or be run through doors or u-a.ffic a reas. The supply c onductors shall be adequately protected from phys ical damage. The supply conductors shall be suitably terminated in an approved manner. The supply conductors shall be supported in an approved manner at least 2.1 m (7 ft) above the floor except at terminations . The supply conductors shall not be bundled. Tap conductors shall be in unbroken lengths.

(F) Supply Conductors Not Reduced in Size. Supply conduc-

tors not reduced in size under 520.54(0) or (E) shall be permitted to pass through holes in walls specifically designed for the purpose. If peneu-ation is throug h the fit-e-1-esi.stantrated wall, it shall be in accordance with 300.21 . (G) Protection of Supply Conductors and Connectors. All supply conductors and connectors shall be protected against physical damage by an approved means. This protection shall not be required to be raceways. (H) Number of Supply Interconnections. Where connectors are used in a supply conductor, there shall be a maximum number of three interconnections (mated connector pairs) where the total le ngd1 from supply to switchboard does not exceed 30 m (100 ft) . In cases wh ere the total length from supply to switchboard exceeds 30 m (100 ft), one additional interconnection shall be permitted for each additional 30 m (100 ft) of supply conductor.

(I) Single-Pole Separable Connectors. \'\'here single-pole portable cable com1ectors a1-e used, they shall be listed and of the locking type. Sections 406.7 and 406.8 shall n ot apply to listed single-pole separable connectors and single-conductor cable assemblies utilizing listed single-pole separable connecto1-s. (J) Supply Neutral Conductor. Supply neuu-al conductors shall comply with 520.54(J)( l ) and (J) (2) .

(l) Marking. Grounded neutral conducto 1-s shall be permitted to be identified by marking at least the first 150 mm (fi in. ) from both ends of each length of conductor \vi th wh ite or gray. (2) Conductor Sizing. Where single-conductor feeder cables not installed in raceways are used o n multiphase circuits feed-

NATIONAL ELECTRICAL CODE

2020 Edition

ARTICLE 520 -THEATERS, MOTION PICTURE & TELEVISION STUDIOS, & SIMILAR LOCATIONS ing portable stage switchboards containing solid-state phasecontrol dimmers, the grounded neuu·al conducto1· shall have an ampacity of at least 130 percent of the ungrounded circuit conductors feeding the portable stage switchboard. Where such feeders are supplying only solid-state sine wave dimmers, the grounded neutral conductor shall have an ampacity of at lea5t 100 percent of the ungrounded circuit conductors feeding the portable stage switchboard. (K) Qualified Personnel. The routing of portable supply conductors, the making and breaking of supply connectors and othe1· supply connections, and the ene1·gization and deenergization of supply services shall be performed by qualified personnel, and portable switchboards shall be so marked, indicating this requirement in a permanent and conspicuous manner. Exce/>tion: A portable switchboard shall be permitted to be connected to a permanently installed supply receptacle by other than qualified personnel provided that the supply receptacle i5 protected for its current rating by an overcurrent device of not greater than 150 amperes, and where the receptacle, interconnection, and switchboard comply with all of the following: ( 1) (2) (3)

They employ listed multipok connectors for every supply interconnection. They prevent access to all supply connections by the general public. They employ li5ted extra-hard usage multiconductor cords or cables with an ampacity not less than the load and not less than the amfJere rating of the connectors.

Part V. Portable Stage Equipment Other Than Switchboards 520.61 Arc Lamps. Arc lamps, including enclosed arc lamps and associated ballasts, shall be listed. Interconnecting cord sets and interconnecting cords and cables shall be extra-hard usage type and listed. 520.62 Portable Power Distribution Units. Portable power distribution unit5 shall comply with 520.62(A) through (F) . (A) Enclosure. The construction shall be such that no currentcarrying part will be exposed. (B) Receptacles and Overcurrent Protection. Receptacles shall comply with 520.45 and shall have branch-circuit overcurrent protection in the box. Fuses and circuit breakers shall be protected against physical damage. Flexible cords or cables supplying pendant receptacles or cord connectors shall be listed for extra-hard usage. (C) Busbars and Terminals. Busbars shall have an ampacity equal to the sum of the ampere ratings of all the circuits connected to the busbar. Lugs shall be provided for the connection of the master cable.

(D) Flanged Surface Inlets. Flanged surface inlets (recessed plugs) that are used to accept the power shall be rated in amperes. (E) Cable Arrangement. Cables shall be protected where they pass through enclosures and be arranged so that tension on the cable is not transmitted to the terminations. (F) Single-Conductor Feeders. Portable power disu·ibution equipment fed by single-conductor feeder systems shall comply with 520.53(C) and (D) and 520.54.

2020 Edition

NATIONAL ELECTRICAL CODE

520.68

520.63 Bracket Fixture Wiring. (A) Bracket Wiring. Brackets for use o n sce ne1·y shall be wired internally, and the fixture stem shall be carried through to the back of the scenery where a bushing shall be placed o n the end of the stem. Externally wired brackets or other fixtures shall be permitted where wired with cords designed for hard usage that extend through scenery and without joint or splice in canopy of fixture back and te1·minate in an approved-type stage connector located, where practical, with in 450 mm (18 in. ) of the fixture. (B) Mounting. Fixtures shall be securely fastened in place.

520.64 Portable Strips. Portable strips shall be consu·ucted in accordance with the requirements fo r border lights and proscenium sidelights in 520.44(A) . The supply cable shall be protected by bush ings where it passes through metal and shall be arranged so that tension on the cable will not be transmitted to the connections. I nformational Note No. I: See 520.42 for wiring of portable Strips. Informational Note No. 2: See 520.68(A)(4) for insu lation types required on single conductors.

520.65 Festoons. Join ts in festoon wiri ng shall be staggered. Where such lampholders have terminals of a type that puncture the insulation and make contact with the conductors, they shall be attached only to cond uctors of the stranded type. Lamps enclosed in lanterns or similar devices of combustible material shall be equipped with guards. 520.66 Special Effects. Electrical devices used for simulati ng lightning, waterfalls, a nd the like shall be constructed and located so that flames, sparks, or hot pa1·ticles can not come in contact with combustible material. 520.67 Multipole Branch-Circuit Cable Connectors. Multipole branch-ci1-cuit cable cormectors, male and female, for flexible conductors shall be constructed so that tension on the cord o r cable is not transmitted to the connections. The female half shall be attached to the load e nd of the power supply cord 01· cable. The connector shall be rated in amperes and designed so that differently rated devices cannot be connected together; however, a 20-ampere T-slot receptacle shall be permitted to accept a 15-ampere attachment plug of the same voltage rating. Alternating-current multipole connectors shall be polarized and comply with 406.7 and 406.10. Informational Note: See 400.14 for pull at terminals.

520.68 Conductors for Portables. (A) Conductor Type. (1) General. Flexible conductors, including cable extensions, used to supply portable stage equipment shall be listed extrahard usage cords or cables. (2) Protected Applications. Listed, hard usage Uunior hard service) cord or cable shall be permitted where all of the following conditions are met: (1)

The cord or cable is protected from physical damage by attachment over its entire leng th to a pipe, tower, truss, scaffold, or other substantial support structure, or installed in a location that inherently prevents physical damage to the cord.

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520.68 (2)

(3)

ARTICLE 520 -THEATERS, MOTION PICTURE & TELEVISION STUDIOS, & SIMILAR LOCATIONS

The cord or cable is connected to a branch circuit protected by an overcurrent protective device rated at not over 20 a mperes. The cord or cable does not exceed 30 m (100 ft) in length.

(3) Stand Lamps. Listed, hard u sage cord shall be permitted

(C) Overcurrent Protection. Overcurrent protection conductors for portables shall comply with 240.5.

of

520.69 Adapters. Adapters, nvo-fers, and other single- and multiple-circuit outlet devices shall comply with 520.69(A), (B), and (C) .

to supply stand lamps where the cord is not subject to physical damage and is protected by an overcurrent device rated at not over 20 amperes.

(A) No Reduction in Current Rating. Each receptacle and its corresponding cable shall have the same current and voltage rating as the plug supplying it. It shall n ot be utilized in a stage circuit with a greater current rating.

(4) Luminaire Supply Cords. Listed hard usage supply cord s shall be permitted to supply luminaires when all of the following conditions are met:

(B) Connectors. AJI connectors shall be wired in accordance with 520.67.

(1) (2)

(3) (4) (5)

The supply co1·d is not longer than 2.0 m (6.6 ft) . The supply cord is attached at one end to the luminaire or a luminaire-specific listed connector that mates with a panel-mowlted inlet on the body of the luminaire. The supply cord is protected by an overcurrent protective device of not more than 20 amperes. The luminaire is listed. The supply cord is not subject to physical damage.

(5) High-Temperature Applications. A special assembly of

conductors in sleeving not longer than 1.0 m (3 .3 ft) shall be permitted to be employed in lieu of flexible cord if the individual wires are stranded and rated not less than 125°C (257°F) and the outer sleeve is g lass fiber with a wall thickness of at least 0.635 mm (0.025 in.). Portable stage equipment requiring flexible supply conductors with a higher temperature rating where one end is permanently attached to the equipment shall be permitted to employ alternate conductors as determined b y a qualified testing laboratory and recognized test standards. (6) Breakouts. Listed, hard usage Uunior hard service) cords shall be permitted in breakout assemblies where all of the following conditions are met:

(1)

(2) (3)

(4)

The cords are utilized to connect benveen a single multipole connector containing nvo or more b1·anch circuit5 and multiple 2-pole, 3-wire connectors. The longest cord in the breakout assembly does not exceed 6.0 m (20 ft). The breakout assembly is protected from physical damage by attachment over its entire length to a pipe, u·uss, tower, scaffold, or other substantial suppon su·u cture. All branch c ircuits feeding the breakout assembly are protected by overcurrent devices rated at not over 20 amperes.

(B) Conductor Ampacity. The ampacity of conductors shall be as given in 400.5, except multiconductor, listed, extra-hard usage portable cords that are not in di1·ect contact with equipment containing heat-producing elements shal l be permitted to have their ampacity determined by Table 520.44(C) (2) . Maximum load current in any conductor with an ampacity determined by Table 520 .44(C) (2) shall not exceed the values in Table 520.44(C) (2) . '1\'here the ampacity adjustment factors of Table 520.44(C)(3) are applied fm more than three currentcarrying conductors in a portable cord, the load diversity shall be 50 percent or less .

(C) Conductor Type. Conductors for adapters and nvo-fers shall be listed extra-hard u sage or listed hard usage Uunior hard service) cord. Hard u sage Uw1 ior hard se rvice) cord shall be restricted in overall length to 2 .0 m (6.6 ft) .

Part VI. Dressing Rooms, Dressing Areas, and Makeup Areas. 520.71 Pendant Lampholders. Pendant lampholders s hall not be installed in dressing or makeup rooms. 520.72 Lamp Guards. AJI exposed lamps in dressing or makeup areas including rooms where they are less than 2 .5 m (8 ft) from the floor shall be equipped with open-end guards riveted to the outlet box cover or otherwise sealed or locked in place. Recessed lamps shall not be required to be equipped with guards. 520.73 Switches Required. All luminaires, lampholders, and any receptacles adjacent to the mirror(s) and above the dressing or makeup counte1·(s) installed in dressing or makeup rooms shall be controlled by wall swi tches installed in the d ressing or makeup room(s) . Other outlets installed in the dressing or makeup rooms shall not be required to be switched. 520.74 Pilot Lights Required. Each switch required in 520.73 shall be provided with a p ilot light located outside of and adjacent to the doo1· of the room be ing controlled to indicate when the circuit is energized. Each p ilot light shall be permanently identified indicating a description of the c ircuit controlled. Pilot lights shall be neon, LED, or other extended-life lamp. Pilot lights shall be recessed or provided with a mechanical guard.

Part VII. Equipment Grounding Conductor 520.81 Equipment Grounding Conductor. All metal raceways and metal-sheathed cables shall be connected to an equipment grounding conductor. The metal frames and enclosures of all equipment, including border lights and ponable luminaires, s hall be connected to an equipment grounding conductor.

Exception: \tWiere alternate conductors are allowed in 520.68(A)(5), their arnpacity shall be as given in the appropriate table in thi5 Code for the types of conductors employed.

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NATIONAL ELECTRICAL CODE

2020 Edition

ARTICLE 522- CONTROL SYSTEMS FOR PERMANENT AMUSEMENT ATTRACTIONS

ARTICLE 522 Control Systems for Permanent Amusement Attractions Part I. General 522.1 Scope. This article covers the installation of control circuit power sources and control circuit conductors for electrical equipment, including associated conu·ol wiring in 01· on all structures, that are an integral part of a permanent amusement am-action . 522.2 Definitions. The definitions in this section shall apply only within this article. Entertainment Device. A mechanical or electromechanical device that provides an entertainment experience. Informational Note: These devices may include animated props, show action equipment, animated figures, and special effects, coordinated with audio and lighting to provide an entertainment experience.

Permanent Amusement Attraction. Ride devices, entertainment devices, or combination thereof, that are installed so that portability or relocation is impracticable. Ride Device. A device or combination of devices that carry, convey, or direct a person (s) over or through a fixed or restricted course within a defined area for the primary purpose of amusement or entertainment. 522.5 Voltage Limitations. Control voltage shal l be a maximum of 150 volts, nominal, ac to ground or 300 volts de to ground. 522.7 Maintenance. The conditions of maintenance and supe1·vision shall ensure that only qualified persons service the permanent amusement attraction.

Part II. Control Circuits 522.10 Power Sources for Control Circuits.

522.23

not exceed 10,000 volt-amperes. These ratings shall be determined with any overcurrent-protective device bypassed. (B) Non-Power-Limited Control Circuits. Non-power-limited control circuits shall not exceed 300 volt~. The power output of d1e source shall not be requi1·ed to be limited.

(1) Control Transformers. Transformers used to supply nonpower-limited control circuits shall comply with the applicable sections within Parts I and II of Article 450. (2) Other Non-Power-Limited Control Power Sources. Nonpower-limited control power sources, other than transformers, shall be protected by overcurrent devices rated at not more than 125 percent of the volt-ampere rating of the source divided by the rated voltage. The fusible overcurrent devices shall not be interchangeable with fusible overcurrent devices of higher ratings. The overcurrent device shall be permitted to be an integ ral part of d1e power source.

Part III. Control Circuit Wiring Methods 522.20 Conductors, Busbars, and Slip Rings. Insulated control c ircuit conductors shall be copper and shall be permitted to be stranded or solid. Listed multiconductor cable assemblies shall be permitted. Exception No. 1: B-usbars and slip rings shall be permitted to be materials other than coppe1: Exception No. 2: Conducton used as specific-pmpose devices, such as thermocouples and resistive thermal devices, shall be permitted to be materials other than coppn:

522.21 Conductor Sizing. (A) Conductors Within a Listed Component or Assembly. Conductors of size 30 AWG or larger shall be permitted within a listed component or as part of the wiring of a I isted assembly. (B) Conductors Within an Enclosure or Operator Station. Conductors of size 30 AWG or larger shall be permitted in a listed and jacketed multico nductor cable within an enclosure or operator station. Conductors in a non-jacketed multiconductor cable, such as ribbon cable, s hall not be smaller than 26 AWG. Single conductors shall not be smaller than 24 AWG.

(A) Power-Limited Control Circuits. Power-limited control circuits shall be supplied from a source that has a rated output of not more than 30 volts and 1000 volt-amperes.

Exception: Single conductors 30 fl WG or larger shall be permitted for jumpers and special wiling applications.

(1) Control Transformers. Transformers used to supp ly powerlimited control circuits shall comply with the applicable sections within Parts I and II of Article 450.

(C) Conductors Outside of an Enclosure or Operator Station. The size of conductors in a listed and jacketed, multiconductor cable shall not be smaller than 26 AWG. Single conductors shall not be smaller than 18 AWG and shall be installed only where part of a recognized wiring method of Chapter 3.

(2) Other Power-Limited Control Power Sources. Powerlimited conu-ol power sources, other than transformers, shall be protected b y overcurrent devices rated at not more than 167 percent of the volt-ampere rating of the source divided b y the rated voltage. The fusible overcurrent devices shall not be interchangeable with fusible overcurrent devices of higher ratings. The overcurrent device shall be permitted to be an integral part of the power sotu-ce . To comply with the 1000 volt-ampere limitation of 522.l O(A), the maximum output of powe1· sources, other than transformers, shall be limited to 2500 volt-amperes, and the product of the maximum current and maximum voltage shall

2020 Edition

NATIONAL ELECTRICAL CODE

522.22 Conductor Ampacity. Ampacities for conductors sized 16 AWG and smalle r shall be as specified in Table 522.22. 522.23 Overcurrent Protection for Conductors. Conductors 30 AvVG through 16 AV•l G shall have overcurrent protection in accordance with the appropriate conducto1· ampacity in Table 522.22. Conductors larger than 16 AWG shall have ove rcurrent protection in accordance with the appropriate conductor ampacity in Table 310.1 6.

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522.24

ARTICLE 525 - CARNIVALS, C IRCUSES, FAIRS, AND SIMlLAR EVENTS

Table 522.22 Conductor Ampacity Based on Copper Conductors with 60°C and 75°C Insulation in an Ambient Temperature of 30°C Ampacity

Conductor Size (AWG)

(1 )

60°C

30 28

26 22

2 3

20 18 16

5 7 10

24

522.25 Ungrounded Control Circuits. Separately derived ac circuits and systems 50 volts or greater and 2-wire d e c ircuits and systems 60 vol ts or greater shall be permitted to be ung rounded, provided that a ll the following conditions a re met:

75°C 0.5 0.8 1 2

3 5 7

(2)

Continuity of control power is required for orderly shutdown. Ground detectors are installed on the control system.

522.28 Control Circuits in Wet Locations. v\The re wet contact is likely to occw~ ungrounded 2-wire direct-current conu·ol circuits shall b e limited to 30 volts maximum for continuous de or 12.4 volts peak for direct current tha t is interrupted at a rate of 10 to 200 Hz.

10

Notes: l. For ambient temperarures other than 30°C , use temperature correction factors provided in 310.lS(B) (1). 2. Ampacity for conductors with 90°C or greater insulation shall be based on ampacities in the 75°C column.

ARTICLE525 Carnivals, Circuses, Fairs, and Similar Events

522.24 Conductors of Different Circuits in the Same Cable, Cable Tray, Enclosure, or Raceway. Control circuits sha ll be permitted to be installed with other c ircuits as specified in 522.24(A) and (B) .

Part I. General Requirements

(A) Tho or More Control Circuits. Control circ uits sha ll be permitted to occupy the same cable, cable u·ay, enclosure, or raceway without regard to whether the individual circuits are alternating current or direct current, provided all conductors are insulated fo1· the maximum voltage of any condu ctor in the cable, cable u·ay, enclosure, or raceway.

525.2 Definitions. The defin itions in this sectio n shall a pply only within this article.

(B) Control Circuits with Power Circuits. Conu·ol circuits shall be permitted to be installed with power conductors as specified in 522.24 (B) (1) through (B) (3) . (I) In a Cable, Enclosure, or Raceway. Control circuits and power circuits shall be permitted to occupy the same cable, enclosure, or raceway o nly wh ere the equipment powered is functionally associated. (2) In Factory- or Field-Assembled Control Centers. Control circuits and power c ircuits shall be permitted to be installed in factory- or field-assembled control centers. (3) In a Manhole. Conu·ol circuits and power circui ts shall be permitted to be installed as underground conductors in a manhole in accordance with one of the following: (1)

(2)

(3)

(4)

The power or control circuit conductors are in a metale nclosed cable or Type U F cable The conductors are pe rman ently separated from the power conductors by a continuous fixed nonconductor, such as flexible tubing, in addition to the insulation on the wire The conductors are permanently and effectively separated from tl1e power conductors and secure ly fasten ed to racks, insulators, or other approved supports In cable u·ays, where the conu·ol circ uit conductors and power cond uctors not functionally associated witl1 them are separated by a solid fixed barrier of a material compatible with the cabl e tray, or where t11e power or control c ircui t conductors are in a metal-enclosed cable

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525.l Scope. This article covers the installation of portable wiring and equipment for carnivals, circuses, fairs, and simila r functions, including wiring in or on a ll stru ctures.

Operator. The individual 1·esponsible for starting, stopping, and controlling an amusement ride or supe rvising a concession. Portable Structures. Units designed to be moved including, but not limited to, amusement rides, atu·actions, concessions, tents, trailers, trucks, and similar units. 525.3 Other Articles. (A) Portable Wiring and Equipment. Wherever the requirements of othe r articles of this Code and Article 525 differ, the requirements of Article 525 sha ll apply to t11 e portable wiring and equipment. (B) Permanent Structures. Articles 518 a nd 520 shall a pply to wiring in permanent strucnires. (C) Audio Signal Processing, Amplification, and Reproduction Equipment. Article 640 sha ll apply to the wiring and installat ion of audio signal processing, a mplification, a nd reproduction equipment.

(D) Attractions Utilizing Pools, Fountains, and Similar Installations with Contained Volumes of Water. This equipment shall be installed to comply with the applicable requirements of Article 680. 525.5 Overhead Conductor Clearances. (A) Vertical Clearances. Conductors sha ll have a vertical clearance to ground in accordance with 225.1 8. These clearances shall apply only to wiring installed outside of tents and concessions.

NATIONAL ELECTRICAL CODE

2020 Edi tion

ARTICLE 525 - CARNIVALS, C IRCUSES, FAIRS, AND SIMILAR EVENTS (B) Clearance to Portable Structures. (1) 600 Volts (or Less). Portable structures shall be maintained not less than 4.5 m (15 ft) in any direction from overhead conductors operating at 600 volts or less, except for the condu cto1·s supplying the portable structure. Porta ble structures included in 525.3(D ) shall comply with Table 680.9(A) . (2) Over 600 Volts. Portable structures shall not be located under or within a space that is located 4.5 m (15 ft) horizontally and extending vertically to grade of conductors operating in excess of 600 volts. 525.6 Protection of Electrical Equipment. Elecu·ical equipment and wiring methods in or on portable structures shall be provided with mechanical protection where such equipment or \vising methods are subject to physical damage.

525.22

(E) Cord Connectors. Cord connectors shall not be la id on the ground unless listed for wet loca tions. Connectors and cable connections shall not be placed in audie nce u·affic paths or within areas accessible to the public unless guarded. (F) Support. Wi1·ing for an amusement ride, attraction, tent, or similar su·ucture shall not be supported by a n y other ride or structure unless specifically designed for the purpose.

(G) Protection. Flexible cords or cables accessible to the public shall be arranged to minimize the tripping hazard and sha ll be permitted to b e covered with nonconductive matti ng secured to the walkway surface or protected with another approved cable protection m ethod, provided that the matting or other protection method does not constitute a greater u·ipping hazard than the uncovered cables. Burying cables shall be permitted. The require men ts of 300.5 shall not apply. (H) Boxes and Fittings. A box or fittin g shall be instal led at

Part II. Power Sources

each connection point, outlet, switchpoint, 0 1·jtmction point.

525.10 Services. Services shall comply with 525.l O(A) and (B) .

525.21 Rides, Tents, and Concessions.

(A) Guarding. Service equipment shall not be installed in a location that is accessible to unqualified persons, unless the equipment is lockable .

(A) Disconnecting Means. A means to disconnect each portable structure from a ll ungrounded conductors shall be provided. The disconnecting mean s shall be located with in sig h t of and within 1.8 m (6 ft) of the operator's station. The disconnecting means shall be readily accessible to th e operator, including when the ride is in operation. Where accessible to unqualified persons, the disconnecting m eans shall be lockable. A shunt trip device tha t opens the fused disconnect or circu it breaker when a switch located in the ride operator's console is closed shall be a permissible method of opening the c ircuit.

(B) Mounting and Location. Service equipment shall be secu rely fastened to a solid backing and be installed so as to be protected from the weather~ unless of weatherproof construction. 525.11 Multiple Sources of Supply. Where multiple services or separately derived systems, or both, supply portable structures, the equ ipment grounding conductors of all the sou rces of supply that serve such structw·es separated by less than 3.7 m ( 12 ft) shall be bonded together at the portable structures. The bonding conductor shall be copper and sized in accordance with Ta ble 250.122 based on the largest overcurrent device supplying the portable structures, but not smaller than 6 AWG.

Part ill. Wiring Methods 525.20 Wiring Methods. (A) Type. \!\There flexible cords or cables a.re used, they shall be listed for extra-hard usage. Where fle xi ble cords or cables are used and a re not subject to physical damage, they sha ll be permitted to be listed for ha.rd usage. Where used outdoors, flexible cords and cables shall also be listed for wet locations and shall be sunlight resistant. Extra-hard usage flexible cords or cables shall be permitted for use as permanent wiring on portable amusement rides and attractions where not subject to physical damage. (B) Single-Conductor. Single-conductor cable shall be permitted only in sizes 2 AWG or larger.

(B) Portable Wiring Inside Tents and Concessions. Elecu·ical wiring for lighting, where installed inside of tents a nd concessions, shall be securely installed and, where subject to physical damage, shall be provided with mechanical protection. All la mps for general illumination shall b e protected from accidental breakage by a luminaire or lampholder with a guard. 525.22 Portable Distribution or Termination Boxes. Portable distribution or termination boxes shall comply with 525.22(A) through (D) . (A) Construction. Boxes sha ll be designed so that no live parts are exposed except when necessary for examination, adjustment, servicing, or maintenance by qualified pe1·sons. \!\There installed outdoors, the b ox sha ll be of weatherproof consnuction and mounted so that the botto m of the enclosure is not less than 150 mm (6 in.) above the ground. (B) Busbars and Terminals. Busbars shall have an a mpere rating not less than the overcurrent device supplying the feeder supplying tl1e box. Where conductors terminate directly on busbars, busbar connectors sha ll be provided.

(C) Open Conductors. Open conductors shall be prohibited except as part of a listed assembly 01· festoon lighting installed in accordance with Article 225.

(C) Receptacles and Overcurrent Protection. Receptacles shall have overcurrent protection installed within tl1e box. The overcurrent protection shall not exceed the ampere rating of the receptacle, except a5 permitted in Article 430 for motor loads.

(D) Splices. Flexible cords or cables shall be conti nuous without splice or tap between boxes or fittings.

(D) Single-Pole Connectors. \!\There single-pole connectors are used, they shall comply with 530.22.

2020 Edition

NATIONAL ELECTRICAL CODE

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525.23

ARTICLE 530 - MOTION PICTURE AND TELEVISION STUDIOS AND SIMILAR LOCATIONS

525.23 Ground-Fault Circuit-Interrupter (GFCI) Protection. (A) Where GFCI Protection Is Required. In addition to the requirements of210.8(B), GFCI protection for personnel shall be provided for the following: (1)

(2)

All 125-volt, single-phase, 15- and 20-ampere non-lockingtype receptacles used for disa5sembly and reassembly or readily accessible to the general public Equipment that is readily accessible to the general public and supplied from a 125-volt, single-phase, 15- or 20ampere branch circuit

The GFCI shall be permitted to be an integral part of the attachment plug or located in the power-supply cord with in 300 mm (12 in.) of the attachment plug. Listed cord sets incorporating GFCI for personnel shall be permitted. (B) Where GFCI Protection Is Not Required. Receptacles that are not accessible from grade level and that only facilitate quick disconnecting and reconnecting of electrical equipment shall not be required to be provided with GFCI protection . These 1-eceptacles shall be of the locking type.

(C) Whe re GFCI Protection Is Not Permitted. Egress Lighting shall not be protected by a GFCI. (D) Receptacles Supplied by Portable Cords. vVhere GFCI

protection is provided through the use of GFCI receptacles, and the branch circuit5 supplying receptacles utilize flexible cord, the GFCI protection shall be listed, labeled, and identified for portable use .

Part IV. Equipment Grounding and Bonding 525.30 Equipment Bonding. Th e following connected to the same source shall be bonded: (1) (2) (3)

equipment

Metal raceways and metal-sheathed cable Metal enclosmes of electrical equipment Metal frames and metal parts of portable structures, trailers, trucks, or other equipment that contain or support electrical equipment

Where the metal frames or parts of the equipment in 525.30(1), (2), or (3) are likely to become energized in the event of a fault, the equipment grounding conductor of the supply circuit shall be permitted to serve as the bonding means. 525.31 Equipment Grounding. All equipment to be grounded shall be connected to an equipment grounding conductor of a type recognized by 250.118 and installed in accordance with Parts VI and VII of Article 250. The equipment grounding conductor shall be connected to the system grounded conductor at the service disconnecting means or, in the case of a separately derived system such as a generator, at the generator or first disconnecting means supplied by the generator. The grounded circuit conductor shall not be connected to the equipment grounding conductor on the load side of the service disconnecting means or on the load side of a separately derived system disconnecting means. 525.32 Equipment Grounding Conductor Continuity Assurance. The continuity of the equipment grounding conductors shall be verified each time that portable electrical equipment is com1ected.

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ARTICLE530 Motion Picture and Television Studios and Similar Locations Part I. General 530.1 Scope. The requirements of this article shall apply to television studios and motion picture studios using either film 01- elecu·onic cameras, except as provided in 520.1, and exchanges, factories, laboratories, stages, or a portion of the building in wh ich film or tape more than 22 mm (% in. ) in width is exposed, developed, prin ted, cut, edited, rewotmd, repaired, or stored. Informational Note: For methods of protecting against cellulose niu·ate film hazards, see NFPA 40-2019, Standard for the Stomge and Handling of Cellulose Nitrate Film.

530.2 Definitions. The definitions in this section shall apply only within this article. Alternating-Current Power Distribution Box (AlternatingCurrent Plugging Box, Scatter Box). An ac distribution center or box that contains one or more grounding-type polarized receptacles that may contain overcurrent protective devices.

Bull Switch. An externally o perated wall-mounted safety switch that may or may not contain overcurrent protection and is designed for the connection of pm-table cables and co1-ds. Location (Shooting Location). A place outside a motion picture studio where a production or part of it is filmed or recorded. Location Board (Deuce Board). Portable equipment containing a lighting contactor or contactors and overcurrent protection designed for remote control of stage lighting. Motion Picture Studio (Lot). A building or group of buildings and other structures designed, constructed, or permanently altered for use by the entertainment industry for the purpose of motion picture or television production. Plugging Box. A de device consisting of one or mo1-e 2-pole, 2wire, nonpolarized, nongrounding-type receptacles intended to be used on de circuits only. Portable Equipment. Equipment intended to be moved from one place to another. Spider (Cable Splicing Block). A device that contains busbars that are insulated from each other for the purpose of splicing or disu-ibuting power to portable cables and cords that are terminated with single-pole busbar connectors. Stage Effect (Special Effect). An electrical or electromechanical piece of equipment used to simulate a distinctive visual or audible effect such as wind mac hines, lighU1ing simulators, sunset projectors, and the like . Stage Property. An article or object used as a visual element in a motion picture or television production, except painted backgrounds (scenery) and cosnunes. Stage Set. A specific area set up with temporaqr scene1y and properties designed and arranged for a particular scene in a motion picture or television production.

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ARTICLE 530 - MOTION PICTURE AND TELEVISION STUDIOS AND SIMILAR LOCATIONS

530.18

Stand Lamp (Work Light). A portable stand that con tains a general-purpose luminaire 01- lampholder with guard for the purpose of providing general illumination in the studio or stage.

530.15 Enclosing and Guarding Live Parts.

Television Studio or Motion Picture Stage (Sound Stage). A building or portion of a building usually insulated from the outside noise and natural light for use by the entertainment industry for the pm·pose of motion picture, television, or commercial production.

(B) Switches. All switches shall be of the externally operable

(C) Rheostats. Rheostats shall be placed in approved cases or cabinets that enclose all live parts, having only the operating handles exposed.

530.6 Portable Equipment. Portable stage and studio lighting equipment and poi-table power disu-ibution equipment shall be permitted for temporary use outdoors if the equipment is supervised by qualified personnel while energized and bar1·iered from the general public.

(D) Current-Carrying Parts. Current-carrying parts of bull switches, location boards, spiders, and plugging boxes shall be enclosed, guarded, 01- located so d1at persons cannot accidentally come into contact with them or bring conductive material into contact with d1em.

Part II. Stage or Set

530.16 Portable Luminaires. Portable luminaires and work lights shall be equipped with flexible cords, composition or metal-sheathed porcelain sockets, and guards.

530.11 Permanent Wiring. The permanent wmng shall be Type MC cable, Type AC cable containing an insulated equipment grounding conductor sized in accordance with Table 250.122, Type MI cable, or in approved raceways. l!,xception: Communications circuits; audio signal processing, amplification, and reproduction circuits; Class 1, Class 2, and Class 3 remotecontrol or signaling circuits and powe1~limited fire alarm circuits shall be permitted to be wired in accordance with Articles 640, 725, 760, and 805.

530.12 Portable Wiring. (A) Stage Set Wiring. The wiring for stage set lighting and othe1- supply wiring not fixed as to location shall be done with Listed hard usage flexible cords and cables. Vl'here subject to physical damage, such wiring shall be listed exu-a-hard usage flexible cords and cables. Splices or taps in cables shall be permitted if the total connected load does not exceed the maximum ampacity of the cable . (B) Stage Effects and Electrical Equipment Used as Stage Properties. The wiring for stage effects and electrical equipment used as stage properties shall be permitted to be wired with single- or multiconductor listed flexible cords 01- cables if the conductors are protected from physical damage and secured to the scenery by approved cable ties or by insulated staples. Splices or taps shall be permitted where such are made with listed devices and the circuit is protected at not more than 20 amperes. (C) Other Electrical Equipment. Cords and cables other than extra-hard usage, where supplied as a part of a listed assembly, shall be permitted.

530.13 Stage Lighting and Effects Control. Switches used for studio stage set lighting and effects (on the stages and lots and on location ) shall be of the externally operable type. V\'here contactors are used as the disconnecting means for fuses, an individual externally operable switch, suitably rated, for the control of each contactor shall be located at a distance of not more than 1.8 111 (6 ft) from d1e contactor, in addition to remote-control switches. A single externally operable switch shall be permitted to simultaneously disconnect all the contactors on any one location board, where located at a distance of not more d1an 1.8 111 (6 ft) from d1e location board. 530.14 Plugging Boxes. Each receptacle of de plugging boxes shall be rated at not less d1an 30 a111pe1-es. 2020 Edition

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(A) Live Parts. Live parts shall be enclosed or guarded to prevent accidental contact by persons and objects. type.

Exception: Portable lwninaires used as properties in a motion picture set or television stage set, on a studio stage or lot, or on location shall not be considered to be pfJrtable luminaires for the pmpose of this section.

530.17 Portable Arc Lamps. (A) Portable Carbon Arc Lamps. Arc lamps shall be provided with an enclosure designed to retain sparks and carbons and to prevent persons or materials from coming into contact with d1e arc or bare live parts. The enclosures shall be ventilated. All switches shall be of d1e externally operable type . (B) Portable Noncarbon Arc Electric-Discharge Lamps. Portable noncarbon arc lamps, including enclosed arc lamps, and associated ballasts shall be listed. Interco1rnecting cord sets and interconnecting cords and cables shall be exu-a-hard usage type and listed.

530.18 Overcurrent Protection - General. Automatic overcurrent protective devices (circuit breakers or fuses) for motion picture studio stage set lighting and d1e stage cables fo r such stage set lighting shall be as given in 530.18(A) through (G) . The maximum ampacity al lowed on a given conductor, cable, or cord size shall be as given in the applicable tables of Articles 310 and 400. (A) Stage Cables. Stage cables for stage set lighting shall be protected by means of overcurrent devices set at not more than 400 percent of d1e ampacity given in d1e applicable tables of Articles 310 and 400. (B) Feeders. In buildings used primarily for motion picture production, d1e feeders from the substations to d1e stages sha ll be protected by means of overcurrent devices (generally located in the substation) having a suitable ampere raring. The overcurrent devices shall be permitted to be multipole 01single-pole gang operated. No pole shall be required in the neuu-al conductor. The overcurrent device setting for each feeder shall not exceed 400 percent of d1e ampacity of d1e feeder, as given in the appl icable tables of Article 310. (C) Cable Protection. Cables shall be protected by bushings where d1ey pass d1rough enclosures and shall be arranged so that tension on the cable is not u-ansmitted to the connections. V\'here power conductors pass throug h metal, the requirements of 300.20 shall apply.

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530.18

ARTICLE 530 - MOTION PICTURE AND TELEVISION STUDIOS AND SIMILAR LOCATIONS

Portable feeder cables shall be permitted to temporarily peneu-ate fire-rated walls, floors, or ceilings provided that all of the following apply: ( 1)

(2) (3)

The opening is of noncombustible material. \!\'hen in use, the penetration is sealed with a temporary seal of a listed fires top material. \!\'hen not in use, the opening shall be capped with a material of equivalent fire rating.

(D) Location Boards. Overcurrent protection (fuses or circuit breakers) shall be provided at the location board~. Fuses in the location boards shall have an ampere rating of not over 400 percent of the ampacity of the cables between the location boa1-ds and the plugging boxes. (E) Plugging Boxes. Cables and cords suppl ied through plugging boxes shall be of copper. Cables and cords smaller than 8 AWG shall be attached to the plugging box by means of a plug contain ing two cartridge fuses or a 2-pole circuit breaker. The rating of the fuses or the setting of the circuit breaker shall not be over 400 percent of the ampacity of the cables or cords as given in the applicable tables of Articles 310 and 400. Plugging boxes shall not be permitted on ac systems. (F) Alternating-Current Power Distribution Boxes. Alternating-current power disu·ibution boxes used on sound stages and shooting locations shall contain connection receptacles of a polarized, grounding type.

(G) Lighting. Work lights, stand lamps, and lumina ires rated 1000 watts or less and connected to de plugging boxes shall be by means of plugs containing two cartridge fuses not larger than 20 amperes, or they shall be permitted to be connected to special outlets on circuits protected by fuses or circuit breakers rated at not over 20 amperes. Plug fuses sha ll not be used unless they are on the load side of the fuse or circuit breakers on the location boards. 530.19 Sizing of Feeder Conductors for Television Studio Sets. (A) General. It shall be permissible to apply tlle demand factors listed in Table 530.19(A) to that portion of the maximum possible connected load for sn1dio or stage set lighting for all permanently installed feeders between substations and stages and to all permanently installed feeders between the main stage switchboard and stage distribution centers or location boards. (B) Portable Feeders. A demand factor of 50 percent of maximum possible connected load shall be permitted for all portable feeders. 530.20 Equipment Grounding Conductor. Type MC cable , Type MI cable, Type AC cable containing an insulated equipment grounding condu cto1~ metal raceways, and all noncurrent-carrying metal parts of appliances, devices, and equip-

Table 530.19(A) Demand Factors for Stage Set Lighting Portion of Stage Set Lighting Load to Which Demand Factor Applied (volt-amperes) First 50,000 or less a t From 50,001 to l 00,000 at From 100,001 to 200,000 at Remaining over 200,000 at

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Feeder Demand Factor (percent)

ment shall be connected to an equipment grounding conductor. This shall not apply to pendant and portable lamps, to portable stage lighting and stage sound equipment, or to other portable and special stage equipment operating at not over 150 volts de to ground. 530.21 Plugs and Receptacles. (A) Rating. Plugs and receptacles, including cord connectors and flanged surface devices, shall be rated in amperes. The voltage rating of the plugs and receptacles sha ll not be less than the nominal c ircuit voltage. Plug and receptacle a mpere ratings for ac circuits shall not be less than the feeder 01· branch-circuit overcurrent device ampere rating. Table 210.21 (B) (2) shall not apply. (B) Interchangeability. Plugs and receptacles used in po1·table professional motion picture and television equipme n t shall be permitted to be interchangeable for ac or de use on the same p1·emises, provided they are listed for ac/ dc use and marked to identify the system to which they are connected. 530.22 Single-Pole Separable Connectors. (A) General. \i\7he1·e ac single-pole portable cable connectors are used, they shall be listed a nd of the locking type. Sections 400 .1 4, 406.7, and 406.8 shall not apply to listed single-pole sepa rable connections and single-conductor cable assemblies utilizing listed single-pole separable connectors. \!\'here paralleled sets of current-carrying single-pole separable connectors are provided as input devices, they shall be prominently labeled with a warn ing indicating the prese nce of internal paralle l connections. The use of single-pole separable connectors shall comply with at least one of the following conditions: (1)

(2)

(3)

Connection and disconnection of connectors are only possible where the supply con nectors are interlocked to tlle source and it is not possible to connect or disconnect connectors when the supply is energized. Line connectors are of the listed seque ntial-interlocking type so that load connectors shall be connected in the following sequence: a. Equipment grounding conductor con nection b. Grounded circuit conductor conne ction, if provided c. Ung1-ounded conductor connection, and tllat disconnection shall be in th e reverse order A caution notice shall be provided adjacent to the line connectors, indicating that plug connection shall be in the follow ing order: a. Equipment grounding conductor connectors b. Grounded c ircuit-conductor connectors, if provided c. Ungrounded conductor connectors, and that disconnection shall be in the reverse order

The warn ing sign(s) or label(s) sha ll comply with 110.21 (B) . (B) Interchangeability. Single-pole separable connectors u sed in portable professional motion picrure and te levision equipment shall be permitted to be interchangeable for ac or de use or for different c urrent ratings on the same premises, provided they are listed for ac/ dc use a nd marked to identify the system to which they are connected.

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ARTICLE 540- MOTION PICTURE PROJECTION ROOMS 530.23 Branch Circuits. A branch circuit of any size supplying one or more receptacles shall be permitted to supply stage set lighting load5.

540.11

(B) Circuit Breaker Frames. Frames of de circuit breakers installed on switchboards shall not be requi1·ed to be connected to an equipment grounding conductor.

The requirements in 210.S(B), other than 210.S(B) (4), shall apply.

Part III. Dressing Rooms 530.31 Dressing Rooms. Fixed wiring in dressing rooms shall be installed in accordance with the wiring methods covered in Chapter 3. Wiring for portable dressing rooms shall be approved.

Part IV. Viewing, Cutting, and Patching Tables 530.41 Lamps at Tables. Only composition or metal-sheathed, porcelain, keyless lampholders equipped with suitable m eans to guard lamps from physical damage and from film and film scrap shall be used at patching, viewing, and cutting tables.

Part V. Cellulose Nitrate Film Storage Vaults 530.51 Lamps in Cellulose Nitrate Film Storage Vaults. Lamps in cellulose n itrate film storage vaults shall be installed in rigid luminaires of the glass-enclosed and gasketed type . Lamps shall be controlled by a switch having a pole in each ungrounded conductor. This switch shall be located outside of the vault and provided with a pilot light to indicate whether the switch is on or off. This switch shall disconnect from all sources of supply all ungrow1ded conductors terminating in any outlet in the vault. 530.52 Electrical Equipment in Cellulose Nitrate Film Storage Vaults. Except as permitted in 530.5 1, no receptacles, outlets, heaters, portable lights, or other portable electrical equipment shall be located in cellulose nitrate film storage vaults. Electric motors shall be permitted, provided they are listed for the application and comply with Article 500, Class I, Division 2.

Part VI. Substations 530.61 Substations. Wiring and equipment of over 1000 volts, nominal, shal l comply with Article 490. 530.62 Portable Substations. \!\' iring and equipment in portable substations shal l conform to the sections applying to installations in permanently fixed substations, but, due to the limited space available, the working spaces shall be permitted to be reduced, provided that the equipment shall be arranged so that the operator can work safely and so that other persons in the vicinity cannot accidentally come into contact with currentcatT},jng parts or bring conducting objects into contact with them whil e they are energized. 530.63 O vercurrent Protection of Direct-Current Generators. Three-wire generators shall have ove1·current protection in accordance with 445.1 2(E) . 530.64 Direct-Current Switchboards. (A) Ge neral. Switchboards of not over 250 volt5 de between conductors, where located in substations or switchb oard rooms accessible to qualified persons only, shall not be required to be dead-front.

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ARTICLE540 Motion Picture Projection Rooms Part I. General 540.1 Scope. This article applies to motion picnire projection rooms, motion picture projectors, and associated equipment of the professional and nonprofessional types using incandescent, carbon arc, xenon, or other light sow-ce equipment that develops hazardous gases, dust, or radiation. Informational Note: For funher information, see NFPA 40-20I9, Standard for the Storage and Handling of Cellulose Nilra/£ Filrn.

540.2 Definitions. The defin itions in this section shall apply only within this a1·ticle. Nonprofessional Projector. Nonprofessional projectors are those types of projectors that do not comply with the definition of Professional-'l)pe Projector. Professional-Type Projector. A type of projector using 35- o r 70-mm film that has a minimum width of 35 mm (1 % in.) and has on each edge 212 perforations per meter (5.4 perforations per in ch), or a type using carbon arc, xenon, or o ther light source equipment that develops hazardous gases, dust, or radiation .

Part II. Equipment and Projectors of the Professional Type 540.10 Motion Picture Projection Room Required. Every professional-type projector shall be located within a projection room. Every projection room sha ll be of permanent construction, approved for the type of building in which the projection room is located. All projection ports, spotlig ht ports, viewing ports, and similar openi ngs shall be pro,,jded with glass or other approved material so as to completely close the o pening. Such rooms shall not be considered as hazardous (classified) locations as defined in Article 500. Informational Note: For further information on protecting openings in projection rooms handling cellulose nitrate motion picture film, see NFPA 101-20I8, Life Safety Code.

540.11 Location of Associated Electrical Equipment. (A) Motor Generator Sets, Transformers, Rectifiers, Rheostats, and Similar Equipment. Motor-generator sets, transformers, rectifiers, rheostats, a nd similar equipment for the supply or conu·ol of current to projection or spotlight equipment shall, where niu·ate film is used, be located in a separate room. Where placed in the projection room, they shall be located or guarded so tllat arcs or sparks cannot come in contact with film, and the commutator end 01· ends of motor-generato1· sets shall comply witl1 one of the conditions in 540.11 (A) (1) through (A) (6) . (1) Types. Be of the totally enclosed, e nclosed fan-cooled, or

enclosed pipe-ventilated Lype.

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540.11

ARTICLE 545 - MANUFACTURED BUILDINGS AND RELOCATABLE STRUCTURES

(2) Separate Rooms or Housings. Be enclosed in separate

rooms or housings built of noncombustible material constn1cted so as to exclude flyings or lint with approved ventilation from a source of clean air. (3) Solid Metal Covers. H ave the brush or sliding-contact end

of motor-generator enclosed by solid metal covers. (4) Tight Metal Housings. H ave brushes or sliding contacts enclosed in tight metal housings. (5) Upper and Lower Half Enclosures. H ave the upper half of

the brush or sliding-contact end of the motor-generator enclosed by a wire screen or perforated metal and the lower half enclosed by solid metal covers. (6) Wrre Screens or Perforated Metal. H ave wire screens or

540.20 Listing Requirements. Projectors a nd enclosures for arc, xenon., and incandescent lamps and rectifiers, u·ansfonners, rheostats, and simi lar equipment shall be listed. 540.21 Marking. Projectors and other eq uipm ent shall be marked with the manufacturer's name or u-ademark and with the voltage and current for whic h they are design ed in accordance witl1 110.21.

Part ID. Nonprofessional Projectors 540.31 Motion Picture Projection Room Not Required. Projectors of the nonprofessio nal or min iature type, where employing cellulose acetate (safety) film , shall be permitted to be operated without a proj ection room.

perforated metal placed at the commu tator of b rush ends. No dimension of any opening in the wire screen or perforated metal shall exceed 1.27 mm (0.05 in .), regardless of the shape of the opening and of the material used.

540.32 Listing Requirements. Projection equip m en t shall be listed.

(B) Switches, O vercurrent Devices, or Othe r Equipment. Switches, overcurrent devices, or other equipment not normally requi1-ed or used for proj ectors, sound reproduction, flood or other special effect lamps, or other equipment shall not be installed i n projection rooms.

Part IV. Audio Signal Processing, Amplification, and Reproduction Equipment

Exception No. 1: In projection rooms approved for use only with cellulose acetate (safety) film, the installation of appurtenant electrical eqitipment used in conjunction with the operation of the projection equipment and the control of lights, curtains, and audio equipment, and so forth, shall be permitted. In such projection rooms, a sign reading "Safety Fi.lm Only Permitted in This Room" shall be posted on the outside of each projection room door and within the projection room itself in a conspicuous location. E-.:ception No. 2: Remote-control switches for the control of auditorium lights or switches for the control ofmotors operating curtains and masking of the motion picture screen shall be permitted to be installed in projection moms. (C) Emergency Systems. Control of emergency systems shall comply with Article 700.

540.12 Work Space. Each motion picture projector, floodlight, spotlight, or similar equipment shall have clear working space not less than 750 mm (30 in. ) wide on each side and at the rear thereof. l'.xception: One such space shall be permitted between adjacent pieces of equipment.

540.13 Conductor Size. Conductors supplying outlets for arc and xenon projectors of the professional type shall not be smaller than 8 AWG and shall have an ampacity not less than the proj ector current rating. Conductors for incandescent-type proj ectors shall conform to nonnal wiring standards as provided in 210.24. 540.14 Conductors on Lamps and Hot Equipment. Insulated conductors having a i-ated operating temperature of not less than 200°C (392°F) shall be used on a ll lamps or other equipment where the a mbient temperature at the conductors as installed will exceed 50°C (122°F) . 540.15 Flexible Cords. Cords approved for hard usage, as provided in Table 400.4, shall be used on portable equipment.

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540.50 Audio Signal Processing, Amplification, and Reproductio n Equipment. Audio signa l processing, amplification, and reproduction equipment sha ll be installed as provided in Article 640.

ARTICLE545 Manufactured Buildings and Relocatable Structures Part I. General 545.1 Scope. This article covers requirements for ma nufactured buildings, building components, relocatable su-uctures, and the conductors that connect relocatabl e structures to a supply of electricity. 545.2 Definitions. The definitio ns in th is se ction sha ll apply only within this article. Building Component. Any subsystem, subassembly, or other system designed for use in or integral with or as pa rt of a su·ucture, wh ich can include structural, elecu-ical , mechanical, plumbing, and fire protection systems, and other systems affecting health and safety. Building System. Plans, specifications, and documentation for a system of manufacnired building or for a type or a system of building components, which can include su·uctural, e lectrical, mechanical, plumbing, and fire protection systems, and other systems affecting health and safety, a nd including such variat ions thereof as are specifi cally pe1·mitted by regulation, and which variations are subm itted as part of the buil d ing system o r amendment thereto. Oosed Construction. Any building, build ing com ponent, assembly, or system manufactured in suc h a man ner that a ll concealed part5 of processes of ma nufacture can not be inspected after installation at th e building site with out d isassembly, damage, or desu-uction.

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ARTICLE 545- MANUFACTURED BUILDINGS AND RELOCATABLE STRUCTURES Manufactured Building. Any building that is of closed consu·uction and is made or assembled in manufacturing facilities on or off the building site for installation, or for assembly and installation on the building site, other than manufacnired homes, mobile h omes, park trailers, or recreational vehicles. Relocatable Structure. A factory-assembled strucnire or structures transportable in one or more sections that are built on a pennanent chassis and designed to be used a5 other than a dwelling unit without a permanent fow1dation. Informational Note: Examples of relocatable su-ucrures are those unilS Lhat are equipped for sleeping purposes on ly, comractor's and other on-site offices, construction job dormitories, studio dressing rooms, banks, clinics, stores, shower facilities and resu-ooms, u-aining cemers, or for the display or demonstration of merchandise or machines.

545.24

grounding, of all exposed metals likely to become energized, in accordan ce with Article 250, Parts V, VI, a nd VII. 545.12 Grounding Electrode Conductor. Provisions shall be made to route a grounding electrode conductor from the service , feeder, or b ranch-circuit supply to the point of attachment to the grounding electrode. 545.13 Component Interconnections. Fittings and connectors that are intended to be concealed at the time of on-site assembly, where tested, ide n tified, and listed to applicable standards, sha ll be permitted for o n-site interconnection of modules o r other building compone n ts. Such fittings a nd connectors shall be equal to the wir ing method e mployed in insulation, temperature rise, and fault-current withstand and shall be capable of endu ring the vibration and minor relative motions occurring in the components of manufactured buildings.

545.4 Wiring Methods. (A) Methods Permitted. All raceway and cable wiring methods included in this Code and oth er wiring syste ms specifically intended and listed for use in manufacnired buildings shall be permitted with listed fittings and with fittings listed and identified for manufactured buildings.

Part II. Relocatable Structures

(B) Securing Cables. In closed construction, cables shall be pennitted to be secu red only at cabinets, boxes, 01· fittings where 10 AWG or smaller conductors are used and protection against physical damage is provided.

545.22 Power Supply.

545.5 Supply Conductors. Provisions shall be made to route the service-entrance condu ctors, undergrow1d service conductors, service-lateral, feeder, or b ranch-circuit supply to the service or building disconnecting means conductors. 545.6 Installation of Service-Entrance Conductors. Serviceen u·ance conductors shall be installed after erection at the building site. Exception: The service-entrance conductors shall be permitted to be installed prior to the erection at the building site where the point of attachment is known prior to manufacture. 545.7 Service Equipment. Service equipment sha ll be installed in accordance with 230 .70. 545.8 Protection of Conductors and Equipment. Protection shall be provided for exposed conductors and equipment during processes of manufacturing, packaging, in u·ansit, and erection at the building site . 545.9 Boxes. (A) Other Dimensions. Boxes of dimensions o ther than those required in Table 314.1 6(A) shall be permitted to be installed where tested, identified, and listed to applicable standards. (B) Not Over 1650 cm3 (100 in.3 ) . Any b ox not over 1650 cm3 (100 in.3 ) in size, intended for mo unting in closed construction, shall be affixed with anchors or clamps so as to p1·ovide a rigid and secure installation. 545.10 Receptacle or Switch with Integral Enclosure. A receptacle 01· switch with integral enclosure and mounting means, where tested, identified, and listed to applicable standards, shall be permitted to be installed. 545.11 Bonding and Grounding. Prewired panels and building components shall provide for the bonding, or bonding and

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545.20 Application Provisions. Relocatable structures shall comply with Part II of this article and the applicable sections of Part I.

(A) Feeder. The feeder shal l include four insulated colorcoded conductors, one of which shall be an equipment grounding conductor. The equipment grounding conductor shall be permitted to be uninsulated if part of a listed cable assembly. I nformational Note: For temporary installation of feeder conductors, see Article 590.

(B) Number of Supplies. Where two or more relocatable strucnu-es are structurally connected to form a sin g le u nit and there is a factory-installed panelboard in each relocatable sU"ucture, each panelboard shall be permitted to be supplied by a separate feeder. (C ) Identification. The identification requireme n ts in 225.37 shall not apply to relocatable strucnires strucn1ra lly connected provided the fo llowing conditions are met: (1)

(2)

The relocatable structures are located on an industrial o r commercial establishment where the conditions of ma intenance and supervision ensure qualified individuals will service the installa tion. The individual panelboard enclosures o r covers have been marked to indicate to location of their supply disconnecting means. The ma rking shall b e visible without removing the cover a nd shall be of sufficient durability to withstand the e nvironment involved.

(D) Grounding. The feeder(s) sh a ll b e grounded in accordance with Parts I, II, and III of Article 250. v\lhere two or more relocatable structures are structurally connected to form a sing le unit, and a common grounding e lectrode conductor and tap arrangement as specified in 250.64( D) (1) is utilized, it shall b e permissible to use the chassis bonding conductor specified in 545.26 as the tap conductor.

545.24 Disconnecting Means and Branch-Circuit Ove rcurrent Protection. (A) Disconnecting Means. A single disconnecting means consisting of a circuit breaker, or a switch and fuses and its

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545.24

ARTICLE 547-AGRICULTURAL BUILDINGS

accessories, shall be provided in a readily accessible location for each relocatable suucture. (B) Branch-Circuit Protective Equipment and Panelboards. Branch-circuit distribution equipment shall be installed in each 1·elocatable structure and shall include over·cmTent protection for each bran ch c ircuit consisting of either circuit brea kers or fuses. Panelboards shall be installed in a readily accessible location. 545.26 Bonding of Exposed Non-Current-Carrying Metal Parts. All exposed non-current-carrying metal parts that are likely to become energized shall be effectively bonded to the grounding terminal or enclosure of the panelboard. A bonding conductor shall be connected between the panelboard and an accessible terminal on the chassis. 545.27 Intersystem Bonding. ' !\There two or more relocatable su·uctures are structurally connected to form a sing le unit, it shall be permissible to install one communication system bonding termination in accordance with 250.94 provided all the following conditions are met: (1) (2)

(3)

There is a factory-installed panelboard in each relocatable su·ucture. The1·e is a bonding conductor between the grounding terminal in each panelboard and chassis in accordance with 545.26. There is a minimum 6 AWG copper conductor that extends from the commun ication system bonding tennination that is connected to each chassis bonding conducto1· required b y 545.26.

The communication bonding termination shall be permitted to be located in the same area as the primary protector or common communications equipment supplying the relocatable structures. 545.28 Ground-Fault Circuit-Interrupters (GFCI). In addition to the requirement5 of 210.S(B), all 1·eceptacle outlet5 installed in compartments accessible from outside the relocatable structure shall have GFCI protection for personnel.

ARTICLE 547 Agricultural Buildings 547.1 Scope . This article applies to the following ag1·icultural buildings or that part of a building or adjacent areas of similar or like nature as specified in 547.l (A) or (B) . (A) Excessive Dust and Dust with Water. Agricultural buildings where excessive dust and dust with water may accumulate, including all areas of p o ultry, livestock, and fish confinement systems, wh ere litter dust or feed dust, including mine1·al feed particles, may accmnttlate. (B) Corrosive Atmosphere. Agricultural buildings where a corrosive atmosphere exists. Such buildings include areas where the following conditions exist: (1) (2)

Poultry and animal excrement may cause corrosive vapors. Corros ive particles may combine with water.

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(3)

(4)

T he area is clamp and wet by reason of periodic washing for cleaning and sanitizing with water and cleansing agents. Similar conditions exist.

547.2 Definitions. The definitions m this section apply only within this article. Distribution Point. An electrical supply point from whic h service drops, service conductors, feeders, o r branch circuits to buildings or structures utilized under single ma nagement are supplied. Informational Note No. 1: Distribution points are also known as the center yard pole, meterpole, or the common distribution point. Informational Note No. 2: The service point as defined in Article 100 is typically at the distribution point.

Equipotential Plane (as applied to agricultural buildings). An area where wire mesh or other conductive element5 are embedded in or placed under concrete, bonded to all metal suuctures and fixed nonelectrical equipment that could beco me energized, and connected to the electrical grounding system to minimize voltage differences within the plane and betwee n the planes, the grounded equipment, and the earth. Site-Isolating Device. A disconnecting means instal led at the distribution point for the purposes of isolation, system maintenance, emergency disconnection, or con nection of optiona l standby systems. 547.3 Other Articles. For buildings and structures not having conditions as specified in 547.1 , the elecu·ical installations shall b e made in accordance with the applicable articles in thi.5 Code. 547.4 Surface Temperatures. Elecu·ical equipment or devices installed in accordance with this article shall be installed in a manner such that they will function at full rating without developing surface temperatures in excess of the specified norma l safe operating range of the equipmen t or device. 547 .5 Wiring Methods. (A) Wiring Systems. Types UF, NMC, copper SE cables, jacketed Type MC cable, rigid nonmetallic conduit, liquidtight flexible nonmetallic conduit, o r other cables or raceways suitable for the locati on, with approved termination fittings, shall be the wiring methods employed. The wiring methods of Article 502, Part II, shall be permitted for areas described in 547.l (A) . Informational Note: See 300.7, 352.44, and 355.44 for installation of raceway systems exposed to widely different temperatures.

(B) Mounting. AU cables sha ll be secured witl1in 200 mm (8 in.) of each cabinet, box, or fitting. Non metallic boxes, fittings, conduit, and cables shall be permitted to be mounted directly to any building surface cove1·ed by this article without maintaining the 6 mm (\t'.i in.) airspace in accordance with 300.6 (D).

(C) Equipment Enclosures, Boxes, Fittings.

Conduit Bodies, and

(1) Excessive Dust. Equipme nt e nclosures, boxes, conduit bodies, and fittings instal led in areas of buildin gs where excessive dust may be present shal l be designed to minimize the entrance of dust and shall have no openings (such as holes fo1·

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ARTICLE 547-AGRICULTURAL BUILDINGS attachment screws) through which dust could enter the enclosure. (2) Damp or Wet Locations. In damp or wet locations, equipment enclosures, boxes, conduit bodies, and fittings shall be placed or equipped so as to prevent moisture from entering or accumulating within the enclosure, box, conduit body, or fitting. In wet locations, including normally dry or damp locations where surfaces are periodically washed 01- sprayed with water, boxes, condttit bodies, and fittings shall be listed for use in wet locations and equipment enclosures shall be weatherproof. (3) Corrosive Atmosphere. Where wet dust, excessive moisture, corrosive gases or vapors, or other corrosive conditions may be present, equipment enclosures, boxes, conduit bodies, and fittings shall have corrosion resistance properties suitable for the conditions. Informational Nore No. I: See Table 110.28 for appropriare enclosure rype designations. Informational Note No. 2: Aluminum and magneric ferrous materials may corrode in agriculrural environmenrs.

(D) Flexible Connections. Where necessary to employ flexible connections, dusttight flexible connectors, liquidtight flexible metal conduit, liquidtight flexible nonmetallic conduit, or flexible cord listed and identified for hard u sage shall be used. (E) Physical Protection. All electrical wiring and equipment subject to physical damage shall be protected. (F) Separate Equipment Grounding Conductor. Where a sepa-

rate equipment grounding conductor, not part of a listed cable assembly, is installed underground within a location falling under the scope of Article 547, it shall be insulated. Informational Note: For further information on aluminum and copper-dad aluminum conductors, see 250.120(B).

(G) Receptacles. Ground-fault circuit-interrupter protection shall be provided as required in 210.S(B) . GFCI protection shall not be 1-equired for othe1· than 125-volt, 15- and 20ampere receptacles installed within the following areas: (1) (2) (3) (4)

Areas having an equipotential plane Outdoors Damp or wet locations Dirt confinement a1-eas for livestock

547.6 Switches, Receptacles, Circuit Breakers, Controllers, and Fuses. Switches, including pushbuttons, relays, and similar devices, receptacles, circuit breakers, contro llers, and foses, shall be provided with enclosures as specified in 547.5(C) . 547.7 Motors. Motors and other rotating electrical machinery shall be totally enclosed or designed so as to minimize the entrance of dust, moisture, or corrosive particles. 547.8 Luminaires. Luminaires shall comply with 547.S(A) through (C). (A) Minimize the Entrance of Dust. Luminaires shall be installed to minimize the entrance of dust, foreign matter, moisture, and corrosive material. (B) Exposed to Physical Damage. Luminaires exposed to physical damage shall be protected by a suitable guard.

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547.9

(C) Exposed to Water. Luminaires exposed to water from condensation, building cleansing water, or solution shall be listed for use in wet locations. 547.9 Electrical Supply to Building(s) or Structure(s) from a Distribution Point. Any agricultural building or structure for livestock located on the same premises shall be supplied from a distribution point. More than one d istribution point on the same p1-emises shall be permitted. The overhead electrical supply shall comply with 547.9(A) and (B) or with 547.9(C) . The underground electrical supply shall comply with 547.9( C) . Any existing agricultural building or structure for other than livestock and any existing buildings and structures not under the scope of Article 547 shall be permitted to be supplied in accordance with 250.32(B) (1) Exception No. l. (A) Site-Isolating Device. Site-isolating devices shall comply with 547.9(A)(l) through (A)(lO) . (1) Where Required. A site-isolating device shall be installed at the distribution point where two o r more buildings or stru ctures are supplied from the distribution point. (2) Location. The site-isolating device shall be pole-mounted and be not less than the height above grade required by 230.24 for the conductors it supplies. (3) Operation. The site-isolating device shall simultaneously disconnect all ungrounded se1vice conductors from the premises wmng. (4) Bonding Provisions. The site-isolating device enclosure shall be connected to the grounded circuit conductor and the grounding electrode system. (5) Grounding. At the site-isolating device, the system grounded conductor shall be connected to a grounding e lectrode system via a grounding electrode conductor. (6) Rating. The site-isolating device shall be rated for the calculated load as determined by Part V of Article 220. (7) Overcurrent Protection. The site-isolating device shall not be required to provide overcurrent protection. (8) Accessibility. The site-isolating device shall be capable of being remotely operated by an operating handle instal led at a readily accessible location. The operating handle of the siteisolating device, when in its highest position, shall not be more than 2.0 m (6 ft 7 in.) above grade or a working platform. (9) Series Devices. An additional site-isolating device for the premises wiring system shall not be required where a siteisolating device meeting all applicable requiremen t5 of this section is provided by the serving utility as part of their service requirements. (IO) Marking. A site-isolating device shall be permanently marked to identify it as a site-isolating device. This ma1-king shall be located on the operating handle or immediately adjacent thereto. (B) Service Disconnecting Means and Overcurrent Protection at the Building(s) or Structure(s). Where the service disconnecting means and overcurrent protection are located at the building(s) or structure(s), the requirements of 547.9(B)(l) through (B) (3) shall apply.

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ARTICLE 550- MOBILE HOMES, MANUFACTURED HOMES, AND MOBILE HOME PARKS

(I ) Conductor Sizing. The supply conductors shall be sized in accordance with Part V of Article 220.

Informational Note No. 1: Methods to establish equipotential planes are described in Ame.-ican Society of Agricultural and Biological Engineers (ASABE) EP473.2-2001 (R2015), Equipown-

(2) Conductor Installation. The supply conductors shall be installed in accordance with the requirements of Part II of Article 225.

lial Planes in Animal Conlain111enl Areas.

(3) Grounding and Bonding. For each building or structure, grounding and bonding of the supply conductors shall be in accordance with the requirements of 250.32, and the following conditions shall be met: (1)

(2)

The equipment grounding conductor is not smaller than the largest supply conductor if of the same material or is adjusted in size in accordance with the equivalent size columns of Table 250.1 22 if of different materials. The equipment grounding conductor is connected to the grounded circuit conductor and the site-isolating device enclosure at the distribution point.

(C) Service Disconnecting Means and O vercurren t Protection at the Distribution Point. The service disconnecting means and overcw-rent protection for each set of feeders or branch circuits shall be located at the distribution point. The service disconnecting means shall be installed in accordance with Part VI of Article 230. The feeders or branch circuits supplied to buildings or structures shall comply with 250.32 and Article 225, Parts I and II. Informational Note: Methods to reduce neutral-to-earth voltages in livestock facilities include supplying buildings or su-uctures with 4-wire single-phase services, sizing 3-wire single-phase service and feeder conductors to limit voltage drop to 2 percent, and connecting loads line-to-line.

(D ) Identification. Where a site is supplied by more than one

distribution point, a permanent plaque or directory shall be installed at each of these distribution points denoting the location of each of the other distribution points and the buildings or structures served b y each . 547.10 Equipotential Planes and Bonding of Equipotential Planes. The installation and bonding of equipotential planes shal l comply with 547.IO(A) and (B) . For the purposes of this section, the term livestock shall not include poultry. (A) Where Required. Equipotential planes shall be installed where required in 547.lO(A)(l) and (A)(2) . (1) Indoors. Equipotential planes shall be installed in confine-

ment areas with concrete floors where metallic equipment is located that may become energized and is accessible to livestock. (2) Outdoors. Equipotential planes shall be installed in connete slabs where metallic equipment is located that may become energized and is accessible to livestock. The equipotential plane shall encompass the area where the livestock stands while accessing metallic equipment that may become energized. (B) Bonding. Equipotential planes shall be connected to the

electrical grounding system. The bonding conductor shall be solid copper, insulated, covered or bare, and not smaller than 8 AWG. The means of bonding to wire mesh or conductive element5 shall be by p1·essure connecto1·s or clamps of brass , copper, copper alloy, or an equally substantial approved means. Slatted floors that are supported by su·uctures that are a part of an equipotential plane shall not require bonding.

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Informational Note No. 2: Methods for safe installation of livestock waterers are described in American Society of Agriculmral and Biological Engineers (ASABE) EP342.3-2010 (R2015), Safely for Ekclrically Heawd Livesloch Walerers.

Informational Note No. 3: Low grounding elecu-ode system resistances may reduce voltage differences in livestock facilities.

ARTICLE550 Mobile Homes, Manufactured Homes, and Mobile Home Parks Part I. General 550.1 Scope. This article covers the electrical conductors and equipment installed within or on mobile and manufactured homes, the conductors that con nect mobi le and manufacttu-ed homes to a supply of electricity, and the installation of electr ical wiring, lumi.nai1·es, equipment, a nd appurtenances related to elecu·ical installati ons within a mobile home park up to the mobile home service-entra nce conductors or, if none , the mobile home se1vice equipment. Informational Note: For additional information on manufactured housing see NFPA 501 -2017, Standard on Manufaclltred Housing, and Part 3280, Manufaclurerl Horne Conslrttclion and Sa/el)' Standards, of the Feder·al Department of H ousing and Urban DevelopmenL

550.2 Definitions. Appliance, Fixed. This definition shall apply only within this article. An appliance that is fastened or otherwise secured at a specific location. Appliance, Portable. This definition shall apply only within this article . An applfance that is actually moved or can easily be moved from one place to another in normal use. Informational Note: For the purpose of this article, the following major appliances, other than built-in, are considered portable if cord connected: refrigerato rs, range equipment, cloth es washers, dishwashers without booster heaters, or other similar appliances.

Feeder Assembly. This defin ition shall apply only within this article. The overhead 01· under-chassis feeder conductors, including the equipment grounding conductor, together with the n ecessary fittings and equipment or a power-supply cord listed for mobile home use, identified for the delivery of energy from the source of electrical supply to the panelboard withi n the mobile home.

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ARTICLE 550-MOBJLE HOMES, MANUFACTURED HOMES, AND MOBJLE H OME PARKS

550.10

thi.~

Park Electrical Wiring Systems. This definition shall apply only within this article.

A structure, transportable in one or more sections, which in the traveling mode is 2.4 m (8 ft) or more in width or 12.2 m (40 ft) or mo1-e in length , or when erected on site is 29.77 m 2 (320 ft2 ) or more is built on a permanent chassis and is designed to be used as a dwelling with or without a permanent foundation, whether or not connected to the utilities, and includes plumbing, heating, air conditioning, and electrical systems contained therein. The term manufactured home includes any structure that meets all the requirements of this paragraph except the size requirements and with respect to which the manufacnirer voluntarily files a certification required by the regulatory agency. Calculations used to determine the number of square meters (square feet) in a structure are based on the strucnire's exterior dimensions and include a ll expandable rooms, cabinets, and other projections containing interior space, but do not include bay windows. [501:1.2.131 For the purpose of this Code and unless otherwise indicated, the term mobile hmne includes manufactured homes and excludes park trailers defined in 552.4.

All of the electrical wi ring, luminaires, equipment, and appurtenances related to electrical installations within a mobile home park, including the mobile home service equipment.

Manufactured Home. This definition shall apply within article and throughout the Code.

Informational Note No. 1: See the applicable building code for definition of the term permanenl foundalion. Informational Note No. 2: See 24 CFR Part 3280, Manufactured Home Conslruclion and Safet)• Standards, of lhe Federal Departmenl of Homing and Urban Development, for additional information on the definition.

Mobile Home. This definition shall apply within this article and throughout the Code. A factory-assembled su-ucture or su-uctures transportable in one or more sections that are built on a permanent chassis and designed to be used as a dwelling without a permanent foundation where connected to the required utilities and that inc lude the plumbing, heating, air-conditioning, and electrical systems contained therein. For the purpose of this Code and unless od1erwise indicated, the term mobile home includes manufactured homes. Mobile Home Accessory Building or Structure. This definition shall apply only wid1in d1is article. Any awning, cabana, ramada, storage cabinet, carport, fence, windbreak, or porch established for the use of the occupant of the mobile home on a mobile home lot. Mobile Home Lot. This definition shall apply only within this article. A designated portion of a mobile home park designed for the accommodation of one mobile home and its accessory buildings or su-ucnll'es for d1e exclusive use of its occupants. Mobile Home Park. This definition shall apply only within this article. A contiguous parcel of land that is used for the accommodation of occupied mobile homes. Mobile Home Service Equipment. This definition shall apply only within this articl e. The equipment containing the disconnecting means, overcurrent protective devices, and receptacles or other means for connecting a mobile home feeder assembly.

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550.4 General Requirements. (A) In Other Than Mobile Home Parks. Mobile homes installed in other than mobile home parks sha ll comply wid1 d1e provisions of this article. (B) Connection to Wiring System. This article shall a pply to mobile homes intended for connection to a wiring system rnted 120/ 240 volts, nominal, 3-wire ac, with a grow1ded neutral conductor. (C) Listed and Labeled. All e lectrical mate1-ials, devices, appliances, fittings, and od1er equipment shall be listed and labeled by a qualified testing agency and shall be connected in an approved manner when i nstalled.

Part II. Mobile and Manufactured Homes 550.10 Power Supply. (A) Feeder. The power supply to the mobile home shall be a feeder assembly consisting of not m ore than one listed 50am pere mobile home power-supply cord or a permanently installed feeder. Exception No. 1: A mobile home that is factory equipped with gas or oilfired central heating equipment and cooking appliances shall be permitted to be provided with a listed mobile home f1owe1~supply cord rated 40 amperes. Exception No. 2: A f eeder assembly shall not be required for manufactured homes constructed in accordance with 550.32(B).

(B) Power-Supply Cord. If the mobile home has a powersupply cord, it shal l be permanently attached to d1e panelboard, or to a junction box perma nently connected to lie panelboard, wid1 the free end terminating in an attachment plug cap. Cords with adapters and pigtail ends, extension cords, and similar items shall not be attach ed to, or shipped with, a mobile home. A suitable clamp or the equivalent shall be provided a t the panelboard knockout to afford su·ain relief for the c01-d to prevent strain from being transmitted to the terminals when the power-supply cord is handled in its intended manner. The cord shall be a listed type with four conductors, one of which shall be identified by a con tinuous green color or a continuous green color \villi one or more yellow su-ipes for use as the equipment grounding conductor. (C) Attachment Plug Cap. The attachment plug cap shall be a

3-pole, 4-wire, grounding type, rated 50 amperes, 125/ 250 volts with a configuration as shown in Figure 550.lO(C) and in tended for use with the 50-ampere, 125/250-volt receptacle configuration shown in Figure 550. IO(C) . It shall be listed, by itself o r as part of a power-supply cord assembly, for the pm-pose and shall be molded to or installed on the flexible cord so that it is secured tightly to the cord at the point where the cord e nters the attachment plug cap. If a 1-ight-angle cap is used, the

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550.10

ARTICLE 550- MOBILE HOMES, MANUFACTURED HOMES, AND MOBILE HOME PARKS conductors as in 550. lO(I) (1) l. The manufacturer shall provide written installation instructions stating the proper feeder conductor sizes for the raceway and the size of the junction box to be used.

configuration shall be oriented so that the grounding member is farthest from the cord. Informational Note: Complete details of the 50-ampere p lug and receptacle configuration can be found in ANSI/ NEMA WD 6-2016, Wiring Devices - Dimensional Specijicalions, Figure 14-50.

(D) Overall Length of a Power-Supply Cord. The overall length of a power-supply cord, measured from the end of the cord, including bared leads, to the face of the attachment plug cap shall not be l ess than 6.4 m (2 1 ft) and shall not exceed 11 m (36!/.i ft) . The length of the cord from the face of the attachment plug cap to the point where the cord enters the mobile home shall not be less than 6.0 m (20 ft) . (E) Marking. The power-supply co1·d shall bear the following marking: FOR USE WITH MOBILE HOMES -

550.11 Disconnecting Means and Branch-Circuit Protective Equipment. The branch-circuit equipment shall be permitted to be combined with the d isconnecting means as a single assembly. Such a combination shall be permitted to be designated as a panelboard. If a fused panelboard is used, the maxim um fuse size for the mains shall be pla inly marked with lettering at least 6 mm (1;;1 in. ) hig h and visible when fuses are changed. Where plug fuses and fuseholders are used, they shall be tam per-resistant Type S, enclosed in dead-front fuse panelboards. Electrical panel boards contain ing circuit breakers shall also be dead-front type.

40 AMPERES Informational Note: See l l0.22 concerning identificatio n of each disconnecting means and each service, feeder, or branch circuit at the poinc where it originated and d1e type marking needed.

or FOR USE WITH MOBILE HOMES -

50 AMPERES

(F) Point of Entrance. The point of entrance of the feeder assembly to the mobile home shall be in the exterior wall, floor, or roof.

(G) Protected. '!\There the cord passes through walls or floors, it shall be protected by means of conduits and bushings or equivalent. The cord shall be permitted to be installed within the mobile home wall5, provided a continuous raceway having a maximum size of 32 mm (1 \I,; in. ) is installed from the branchcircuit panelboard to the underside of the mobile home floor. (H) Protection Against Corrosion and Mechanical Damage. Permanent provisions shall be made for the protection of the attachment plug cap of the power-supply cord and any connector cord assembly or receptacle against cotTosion and mechanical damage if such devices are in an exterior location wh ile the mobile home is in n·ansit.

(A) Disconnecting Means. A sing le d isconnecting means shall b e provided in each mobile home consisting of a c ircuit breaker, 01· a switch and fuses and its accessories installed in a readily accessible location near the point of entrance of the supply cord or conductors into the m obile home. The main circuit breakers or fuses shall be plainly marked "Main." This equipment shall contain a solde rless type of grounding connector or bar for the purposes of grounding, with sufficient terminals for all grounding conductors. The terminations of the grounded circuit conductors shall be insulated in accordance with 550 .16(A) . The disconnecting equipment shall have a rating not less than the calculated load. The distribution equipmen t, e ither circuit breaker or fused type, shall be located a minimum of 600 mm (24 in .) from the bottom of such equipment to the floor level of the mobile home. Informational Note: See 550.20(B) for information on disconnecting means for branch circuits designed to energize heating or air-cond itioning equipment, o r both, located outside the mobile home, other than room air conditione rs.

(I) Mast Weatherhead or Raceway. '11\There the calculated load exceeds 50 amperes or where a permanent feeder is used, the supply shall be by means of either of the following: (1)

(2)

One mast weatherhead installation, installed in accordance with Article 230, containing four continuous, insulated, color-coded feeder conductors, one of which shall be an equipment grounding condu ctor A metal raceway or rigid nonmetailic conduit from the disconnecting means in the mobile home to the underside of the mobile home, with provisions for the attachment to a suitable junction box or fitting to the raceway on the underside of the mobile home fwith or with out

Receptacle

~ ~ 125/250-V, 50-A, 3-pole, 4-wire, grounding type

FIGURE 550.IO(C) 50-Ampere, 125/ 250-Volt Receptacle and Attachment Plug Cap Configurations, 3-Pole, 4-Wrre, Grounding-Types, Used for Mobile Home Supply Cords and Mobile Home Parks. 70-474

A panelboard shal l be rated not less than 50 amperes and employ a 2-pole circuit breaker ra ted 40 a mperes for a 40ampere supply cord, or 50 amperes for a 50-ampere supply cord . A panelboard employing a disconnect switc h and fuses shall be rated 60 amperes and shall employ a s ingle 2-pole, 60ampere fuseholder with 40- or 50-ampere ma in fuses for 40- 01· 50-ampere supply cords, respectively. The ou tside of the panelboard shall be plainly marked with the fuse size. The panelboa1·d sh a ll be located in a n accessible location but shall not be located in a bathroom or a clothes closet. A clear working space at least 750 mm (30 in .) wide and 750 mm (30 in.) in front of the panelboard shall be provided. This space shall extend from the floor to the top of the pane lboard. (B) Branch-Circuit Protective Equipment. Branch-circuit distribution equipment shall be installed in each mobile home and shall include overcurrent protection for each branch circuit consisting of either circuit breakers or fuses.

The branch-circuit overc UtTent devices shall be rated as follows: (1)

Not more than the circuit conductors; and

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ARTICLE 550-MOBJLE HOMES, MANUFACTURED HOMES, AND MOBJLE H OME PARKS (2)

(3)

Not more than 150 percent of the rating of a single appliance rated 13.3 amperes or more that is supplied b y an individual branch circuit; but Not more than the overcurrent protection size and of the type marked on the air conditioner or other motor· operated appliance.

(C) Two-Pole Circuit Breakers. '"'here circuit breakers are provided for branch-circuit protection, 240-volt circui ts shall be protected by a 2-pole com mon o r companion trip, or by circuit breakers with identified handle ties.

receptacle outlets in the kitchen and other locations specified in 550.12(B) . (C) Laundry Area. Where a laundry area is provided, a 20ampere branch circu it shall be provided to supply the laundry receptacle outlet(s) . This circuit shall have no other outle ts. (D) General App liances. (Including furna ce, water heater, range, and central or room air conditioner, etc.) . There shall be one or more circ uits of adequate rating in accordance with the following: l nformational Nore: Fo r central air conditioning, see Article 440.

(D) Electrical Nameplates. A metal nameplate on the ou tside adjacent to the feeder assembly entrance shall read as follows: (1) IBIS CONNECTION FOR 120/ 240-VOLT, 3-POLE, 4-vVIRE, 60-HERTZ, AMPERE SUPPLY The correct ampere rating shall be marked in the blank space. Exception: }'!Jr manufactured homes, the manufacturer shall provide in its written installation instructions or in the data plate the minimum ampere rating of the feeder assembly 01; where provided, the serviceentrance conductors intended for connection to the manufactured home. 77ie rating provided shall not be less than the minimum load calculated in accordance with 550.18.

550.13

(2)

(3)

( 4)

The ampere rating of fixed appliances shall be not over 50 percent of tl1e c ircui t rating if lighting outlets (receptacles, other than kitchen , dining area, and laundty, con sidered as lighting outlets) are on the same circuit. For fixed appl iances on a circuit without lighting outlet5, the sum of rated amperes shall not exceed the branchcircuit rating. Motor loads 01- continuous loads shall not exceed 80 percent of the branc h-circuit rating. The rating of a single cord-andcplug-connected appliance on a circuit having n o other outlets shall not exceed 80 percent of the circuit rating. The rating of a range branch circuit shall be based on the range demand as specified for ranges in 550.18(B) (5 ) .

550.12 Br anch Circuits. T he number of branch circuits required shall be determined in accordance with 550.12 (A) through (E) .

(E) Bathrooms. Bathroom receptacle outlets shall be supplied by at least one 20-ampere branch circuit. Such circuits shall have no outlets other than as provided for in 550.13(E) (2) .

(A) Lighting. The number of branch c ircuits shall be based on 33 volt-amperes/m 2 (3 VA/ ft2 ) times outside dimensions of the mobile h ome (coupler excluded) divided by 120 volts to determine the number of 15- or 20-ampere lighting area circuits, for example,

550.13 Recep tacle Outlets.

[550. 12(A) ] 3 x length x width 120 x 15 (or 20) No. of15- (or 20-) ampe1-e circuits (B) Small Ap p liances. In kitchens, pantries, d ining rooms, and breakfast rooms, two or more 20-ampere small-appliance circuits, in addition to the number of circuits required elsewhere in this section, shall be provided for all receptacle outlets required by 550.13(D) in these rooms. Such circuits shall have no other outlets. Exception No. 1: Receptacle outlets installed solely for the electrical supply and support of an electric clock in any the roorns specified in 550.12(B) shall be pe1mitted. Exception No. 2: Receptacle outlets installed to provide power for supplemental equipment and lighting on gas-fired ranges, ovens, or countei~mmmted cooking units shall be permitted. Exception No. 3: A single receptacle f01· reftigeration equipment shall be permitted to be supplied from an individual branch circuit rated 15 amperes or greate1:

Countertop receptacle outlets installed in the kitchen sha ll be supplied by not less tl1an two small-appliance c ircuit branch circuits, either or b o th of which shall be permitted to supply

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(A) Grounding-Type R ecep tacle Outlets. All receptacle outlets shall comply with the following: (1 )

(2) (3)

Be of grounding type Be installed according to 406.4 Except where supplying specific appliances, be 15- o r 20ampere, 125-volt, either single or multiple type, and accept parallel-blade attachment plugs

(B) Ground-Fault Circuit Inte rrupters (GFCI) . Ground-fau lt circuit-interrupter protection shall be provided as required in 210.8(A) . GFCI protection shall not b e requi1-ed for other than 125-volt, 15- and 20-ampere receptacles installed within a mobile or manufactured home in the following areas: (l) (2) (3) (4)

(5)

Compartmen ts accessible from outside the tmit Bathrooms, including receptacles in luminaires Kitchens, where receptacles a re installed to serve counte rtop surfaces Sinks, where receptacles are installed within 1.8 m (6 fr) from the top inside edge of the sink Dishwashers Informational Note: For information on protectio n of dishwashers, see 422 .5.

(C) Co rd-Connected Fixed Appliance. A grou nding-type receptacle outlet shall be provided for each cord-co1mected fixed appliance installed . (D) Recep tacle O utlets Re quired. Except in the bath, closet, and hallway areas, receptacle outlets sha ll be installed at wall spaces 600 mm (2 ft) wide or more so that no point along the floor line is m ore than 1.8 m (6 ft) measured horizontally from an outlet in that space. In addition, a receptacle o utlet shall be installed in the following locations:

70-475

550.13 (1)

(2)

(3) ( 4)

(5) (6) (7) (8)

(9)

ARTICLE 550- MOBILE HOMES, MANUFACTURED HOMES, AND MOBILE HOME PARKS

Over or adjacent to countertops in the kitchen (at least one on each side of the sink if countertops are on each side and are 300 mm (12 in.) or over in width l . Adjacent to the refrigerator and freestanding gas-range space . A multiple-type receptacle shall be permitted to serve as the outlet for a countertop and a refrigerator. At countertop spaces for built-in vanities. At countertop spaces under wall-mounted cabinets. In the wall at the nearest point to where a bar-type counter attaches co the wall. In the wall at the neai-est point to where a fixed room divider attaches to the wall. In laundry areas within 1.8 m (6 ft) of the intended location of the laundry appliance (s) . At least one receptacle outlet located outdoors and accessible at grade level and not more than 2 .0 m (6~ ft) above grade. A receptacle outlet located in a compartment accessible from the outside of the unit shall be considered an outdoor receptacle. At least one receptacle outlet shall be installed in bathrooms within 900 mm (36 in.) of the outside edge of each basin. The receptacle outlet shall be located above or adjacent to the basin location. This receptacle shall be in addition to any receptacle that is a part of a luminaire or appliance. The receptacle shall not be enclosed within a bathroom cabinet or vanity.

(E) Pipe Heating Cable(s) Outlet. For the connection of pipe

heating cable(s), a receptacle outlet shall be located on the underside of the unit as follows: (1) (2)

(3) ( 4)

Within 600 mm (2 ft) of the cold water inlet. Cormected to an intei-ior branch circuit, other than a small-appliance branch circuit. It shall be permitted to use a bathroom receptacle circuit for this purpose. On a circuit where all of the outlets ai-e on the load side of the ground-fault circuit interrupter. This outlet shall not be considered as the receptacle required by 550.13(D) (8) .

(F) Receptacle Outlets Not Permitted. Receptacle outlets shal l not be permitted in the following locations:

(1) (2) (3)

Receptacle outlets shall not be installed within or directly over a bathtub or shower space. A receptacle shall not be installed in a face-up position in any countertop. Receptacle outlets shall not be installed above electric ba5eboard heaters, unless provided for in the listing or manufactw-er's instructions.

(G) Receptacle Outlets Not Required. Receptacle outlets shall

(B) Accessibility. Every appliance shall be accessible for inspection, service, repair, or replacement without removal of permanent conso-uction .

(C) Pendants. Listed pendant-type luminaires or pendant coi-ds shall be permitted. (D) Bathtub and Shower Luminaires. \'\'here a lum inaire is

installed over a bathtub or in a shower stall , it shall be of the enclosed and gasketed type listed for wet locations. 550.15 Wiring Methods and Materials. Except as specifically limited in this section, the wiring methods and materials included in this Code shall be used in m obile homes. Aluminum conductors, aluminum alloy conductors, and aluminum core conductors such as copper-clad aluminum shall be permitted for use where used with equipment listed fo1· aluminum conductor connections. (A) Nonmetallic Boxes. Nonmetallic boxes shall be permitted

only with nonmetallic cable or nonmetallic raceways. (B) Nonmetallic Cable Protection. Nonmetallic cable located 380 mm (15 in.) or less above the floor, if exposed, shall be protected from physical damage by covering boai-ds, guard su-ips, or raceways. Cable likely to be damaged by stowage shall be so protected in all cases. (C) Metal-Covered and Nonmetallic Cable Protection. Metalcovered and nonmetallic cables shall be permitted to pass through the centers of the wide side of 2 by 4 studs. However, they shall be protected where they pass through 2 by 2 studs 0 1at otl1er studs or frames where the cable or armor would be less than 32 mm (lY.1 in.) from the inside or outside surface of tl1e studs where the wall covering materials are in contact with the studs. Steel plates on each side of the cable, or a tube, with not less than 1.35 mm (0.053 in.) wall thickness shall be requii-ed to protect the cable. These p lates or tubes shall be securely held in place. (D ) Metal Faceplates. Where me tal faceplates are used, the

installation shall comply with 404.9(B) and 406.6(B) . (E) Installation Requirements. Where a range, clotl1es dryer, 01- other appliance is connected by metal-covered cable or flexible metal conduit, a lengtl1 of not less tlrnn 900 mm (3 ft) of unsupported cable or conduit shall be provided to service the appliance. The cable or flexible metal conduit shall be secured to the wall. Type NM or Type SE cable shall not be u sed to connect a range or dryer. This s hall not prohibit the use of Type NM or Type SE cable between t he branch-circuit overcurrent protective device and a junction box or range or dryer receptacle.

not be required in the following locations: (1) (2) (3)

( 4)

In the wall space occupied by built-in kitchen or wardrobe cabinets In tl1e wall space behind doors that can be opened fully against a wall surface In room dividers of the lattice type that are less than 2 .5 m (8 ft) long, not solid, and within 150 mm (6 in.) of the floor In the wall space affm-ded by bar-type counters

(F) Raceways. 'l\7he1-e rigid metal conduit or intermediate metal conduit is terminated at an enclosure with a locknut and bushing connection, two locknuts shall be provided, one inside and one outside of the enclosure . Rigid nonmetallic conduit, elecn-ical nonmetallic tubing, or surface raceway shall be permitted. All cut ends of conduit and tubing shall be reamed or otherwise finished to remove rough edges. (G) Switches. Switches shall be rated as fo llows:

550.14 Luminaires and Appliances.

(1)

(A) Fasten Appliances in Transit. Means shall be provided to securely fasten appliances when the mobile home is in transit. (See 550.1 6 for provisions on grounding.)

(2)

70-476

For Lighting circuits, switches shall be rated not less than 10 amperes, 120 to 125 volts, and in no case less than the connected load. Switches for motor or other loads shall comply with 404.1 4 .

NATIONAL ELECTRICAL CODE

2020 Edition

ARTI CLE 550-MOBJLE H OMES, MANUFACTURED H OMES, AN D MOBJLE H OME PARKS (H ) U nd er-Chassis Wiring (Exposed to Weather ). ( 1) V\There outdoor or under-chassis line-voltage (120 volts, nominal, or h igher) wiring is exposed, it shall be protected by a conduit or raceway identified for use in wet locations. T he conducto1·s shall be listed for use in wet locations. (2) Where wiring is exposed to physical damage, it shall be protected by a raceway, conduit, or other means. (I) Boxe s, Fittings, and Cabine ts. Boxes, fittings, and cabinets shal l be securely fastened in place and shall be supported from a structural mem ber of the home, either d irectly or by using a substantial brace. Exception: Snap-in-type boxes. Boxes provided with special wall or ceiling brackets and wiring devices with integral enclosures that securely fas ten to walL~ or ceilings and are identified for the use shall be permitted without support jivm a structural member or brace. The testing and appmval shall include the wall and ceiling construction systems for which the boxes and devices are intended to be used.

(J) Appliance Terminal Conn ections. Appliances having b ranch-circuit terminal connections that operate at temperatures higher than 60°C (140°F) shall have circuit conductors as described in the foll owing:

( 1)

(2)

Branch-circuit conductors having an insulation suitable for the temperature encountered shall be permitted to be run d irectly to the appliance. Conductors having an insulation suitable fo1· the temperature encountered shall be run from the appliance term inal connection to a readily accessible outlet box placed at least 300 mm (1 ft) from the appliance. These conductors shall be in a suitable raceway or Type AC or MC cable of at least 450 mm (18 in.) but not more than 1.8 m (6 ft) in length.

(K) Component Interconnections. Fittings and connectors that are intended to be concealed at the time of assembly shall be listed and identified for the interco1mection of building components. Such fittings and connectors shall be eq ual to the wiring method employed in insulation, temperature rise, and fault-current withstanding and shall be capable of enduring the vibration and shock occurring in mobile home transportation . Informational Note: See 550.19 for inte rconnection of multiple section units.

550.16 Grounding. Grounding of both e lectrical and nonelectrical metal pa1·ts in a mobile home shall be through connection to a grounding bus in the mobile home panelboard and shall be connected through the green-colored insulated conducto1· in the supply cord or the feeder wiring to the grou nding bus in the service-entrance equipment located adjacent to the mobi.le home location. Neither the frame of the mobile home nor the frame of any appliance shal l be connected to the grounded circuit conductor in the mobi le home. V\'here the pane lboard is the service equipment as permitted by 550.32(B), the neutral conductors and the equipment grounding bus shall be connected . (A) Grounded Conductor. ( 1) Insulated. T he g1·ounded circuit conductor shall be insulated from the grounding conductors and from equipment enclosures and other grounded parts. The grounded circuit conducto1· terminals i n the panelboard and in ranges, clothes dryers, cou nter-mounted cooking un its, and wall-mou nted

2020 Edition

NATIONAL ELECTRICAL CODE

550.16

ovens shall be insulated from the equipme n t enclosure. Bonding screws, straps, 01· buses in the panelboard or in a p pliances shall be removed and d iscarded. V\'here the panelboard is the service equipment as perm itted by 550.32(B), the neutral conductors and the equipment grounding bus sha ll be connected. (2) Connections o f Ranges and Clothes Dryers . Connections of ranges and clothes dryers with 120/ 240-volt, 3-wi re ratings shall be made with 4-conductor cord and 3-pole, 4-wi re, grounding-type pl ugs or by Type AC cable, Type MC cable, o r conductors enclosed in flex ible metal conduit. (B) Equipment G rounding Means.

(1) Supply Cord or Permanent Feeder. Th e green-colored insulated grounding wire in the supply COITl or permanent feeder wiring shall b e con nected to the ground ing bus in th e panelboard or d iscon necting means. (2) Electrical System. In the electrical system, a ll exposed metal parts, enclostu-es, fra mes, lum ina i re canopies, and so forth, shall be effectively bonded to the ground ing terminal or enclosure of the panelboard. (3) Cord-Connected Appliances. Cord-connected applian ces, such as washing machines, clothes dryers, a nd refrigerators, and the e lectrical system of gas ranges and so fo1·th, shall be grounded by means of a cord with an equipme n t ground ing conductor and grounding-type attachment plug. (C) Bonding of N on-Current-Carrying Metal Parts.

(1) Exposed Non- Current-Carrying Metal Parts. All exposed non-current-carrying metal parts that are likely to become energized shall be effectively bonded to tlle grounding terminal or enclosure of the panelboard. A bonding conductor sha ll be connected between th e panelboard and a n accessible terminal on the chassis. (2) Grounding Terminals. G rounding termina ls shall be of the solderless type and listed as p ressure-terminal connectors recognized for the wire size used. The bond ing conducto1· shall be solid or stranded, insulated or bare, and shall be 8 AWG copper minimum, or equivalent. The bonding conductor shall be routed so as not to be exposed to p h ysical damage. (3) Me tallic Piping and Ducts. Metallic gas, water, a nd waste pipes and metallic a ir-circulating ducts sha ll be considered bonded if they are connected to tlle terminal on the chassis fsee 550.1 6(C) (l)] by clamps, solderless con nectors, or b y suitable grounding-type su·aps. (4) Metallic Roof and Exterior Coverings. Any metallic roof and exterior covering shall be considered bonded if the fo llowing conditions are met: (1)

(2)

T he metal panels overlap one anotl1er and are securely attached to the wood o r metal frame parts by metallic fastene1·s. The lower panel of the me tallic exterior covering is secu red by metallic fasteners at a cross member of the chassis by two metal straps per mobile home unit or section at opposite e nds.

T he bonding strap material shall b e a min im u m of 100 m m (4 in .) in width of mate1·ial equivalent to the skin or a materia l of equal or better e lecu·ical conductivity. The straps shall be fastened with paint-peneu·ating fittings such as screws and starwashers or equivalen t.

70-477

550.17

ARTICLE 550- MOBILE HOMES, MANUFACTURED HOMES, AND MOBILE HOME PARKS

550.17 Testing. (A) Dielectric Strength Test. The wiring of each mobile home shall be subjected to a 1-minute, 90(}-volt, dielectric su-ength test (with all switches closed) between live parts (including neutral conductor) and the mobile home ground. Alternatively, the test shal l be permitted to be performed at 1080 volts for l second. This test shall be performed after branch circuits are complete and after luminaires or appliances are installed.

Exception: Listed luminaires or appliances shall not he required to withstand the dielectric strength test. (B) Continuity and Operational Tests and Polarity Checks. Each mobile home shall be subje cted to all of the following: (l )

(2)

(3)

An e lectr·ical continuity test to ensure that all exposed elecu-ically conductive parts are properly bonded An electrical operational test to demonsu-ate that all equipment, except water heaters and electric furnaces, is connected and in working order Electrical polarity checks of permanently wired equipment and 1·eceptacle outlets to detennine that connections have been properly made

550.18 Calculations. The following method shall be employed in calculating the supply-cord and distribution-panelboard load for each feeder assembly for each mobile home in lieu of the procedure shown in Article 220 and shall be based on a 3-wire, 120/ 24(}-volt supply with 12(}-volt loads balanced between the two ungrounded conductors of the 3-wire system. (A) Lighting, Small-Appliance, and Laundry Load. (1) Lighting Volt-Amperes. Length times width of mobile home floor (outside dimensions) times 33 volt-amperes/ m 2 (3 VA/ ft2 ), for example, lengt11 x widt11 x 3 = lighting voltamperes. (2) Small-Appliance Volt-Amperes. Number of circuits times 1500 volt-amperes for each 2(}-ampere appliance 1·eceptacle circuit (see definition of Appliance, P11rtab!.e, with an informational note in 550.2), foi- example, numbe1· of circuits x 1500 = small-appliance volt-amperes.

(3) Laundry Area Circuit Volt-Amperes. 1500 volt-amperes. (4) Total Volt-Amperes. Lighting volt-amperes plus smal lapplian ce volt-amperes plus laundry area volt-amperes equals total volt-amperes.

(5) Net Volt-Amperes. First 3000 total volt-ampe1·es at 100 percent plus remainder at 35 percent equa ls volt-amperes to be divided by 240 volts to obtain current (amperes) per leg. (B) Total Load for D etermining Power Supply. Total load for determining power supply is the sum of the following: (1) (2)

(3)

Lighting and small-appl iance load as calculated in 550.1 8(A) (5 ). Nameplate amperes for motors and heater loads (exhaust fans, air conditione1·s, e lectric, gas, or o il heating) . Omit smaller of the heating and cooling loads, except include blower motor if used as air-conditioner evaporator motor. Where an air conditioner is not installed and a 4(}-ampere power-supply cord is provided, allow 15 amperes per leg for air condition ing. Twenty-five percent of current of largest motor in item (2) .

70-478

( 4)

(5)

(6)

Total of nameplate amperes for waste disposer, dishwasher, wate1· heater, clothes dryer, wall-mounted oven, cooking units. V\lhere the number of these applia nces exceeds three, use 75 percent of total. Derive amperes for freestanding range (as distinguished from separate ovens and cooking units) by d ividing the following values by 240 volt5 as shown in the following table. If outlets or c ircuits are provided for other than factoryinstalled appliances, include the anticipated load. Informational Nole: Refer lo Informative Annex D, Example DI 1, for an illusrration of lhe application of lhis calculation.

Nameplate Rating

Use (volt-amperes)

(watts)

0-10,000 Over 10,000-12,500 Over 12,500-13,500 Over 13,500-14,500 Over 14,500-15,500 Over 15,500-16,500 Over 16,500-17,500

80 percent of rating 8,000 8,400 8,800 9,200 9,600 10,000

(C) Optional Method of Calculation for Lighting and Appliance Load. The optional method for calculating lighting and appliance load shown in 220.82 shall be permitted.

550.19 Interconnection of Multiple-Section Mobile or Manufactured Home Units. (A) Wiring Methods. Approved and listed fixed-type wiring methods shall be used to j oin portions of a circuit that must be elecu-ically j oined and are located in adjacent sectio ns after the home is installed on its support foundation . The circuit's junction shall be accessible fo1· disassembly when the home is prepared for relocation. Informational Note: See 550.15 (K) for componem imerconnections.

(B) Disconnecting Means. Expandable or multiunit ma nufactured homes, not having permanently installed feeders, that are to be moved from one location to a nother shall be permitted to have disconnecting means with bran ch-circuit protective equipment in each unit when so located that after assembly 01· joining together of uni ts, the requirements of 550.1 0 wil l be met.

550.20 Outdoor Outlets, Luminaires, Air-Cooling Equipment, and So Forth. (A) Listed for Outdoor Use. Outdoor luminaires and equipment shall be listed for wet locations or outdoor use. Outdoo1· receptacles shall comply wi tl1 406.9. Vl'here located o n the underside of the home o r located under roof exte nsions or s imilarly p1·otected locations, outdoor luminai1·es and equipmen t shall be listed for use in damp locations. (B) Outside Heating Equipment, Air-Conditioning Equipment, or Both. A mobile home provided with a branch circuit designed to energize outside heating equipment, airconditioning equipment, or both, located outside the mobile home, other than room air conditioners, shall have such branch-circuit conductors terminate in a listed outle t box, or disconnecting means, located on the outside of the mobile

NATIONAL ELECTRICAL CODE

2020 Edi tion

ARTICLE 550-MOBJLE HOMES, MANUFACTURED HOMES, AND MOBJLE HOME PARKS home. A label shall be permanently affixed adjacent to the outlet box and shall contain tl1e following information: THIS CONNECTION IS FOR HEATING AND/OR AIR-CONDITIONING EQUIPMENT. THE BRANCH CIRCUIT IS RATED AT NOT MORE THAN _ _ AMPERES, AT _ _ VOLTS, 60 HERTZ, CONDUCTOR AMPACI1Y A DISCONNECTING MEANS SHALL BE LOCATED v\TITHIN SIGHT OF THE EQUIPMENT. The correct voltage and ampere rating shall be given . The tag shall be not less than 0. 51 mm (0.020 in.) iliick etched brass, stainless steel, anodized or alclad aluminum, or equivalent. The tag shall not be less than 75 mm by 45 mm (3 in. by 1o/,\ in.) minimum size. 550.25 Arc-Fault Circuit-Interrupter Protection. (A) Definition. Arc-fault circuit interrupters are defined in Article l 00.

equipment shall be located in sight from and not more than 9.0 m (30 ft) from the exterior wall of me mobile home it serves. The service equipment shall be permitted to be located elsewhere on the premises, if a d isconnec ting means suitable for use as service equipment is located within sig ht from and not more man 9.0 m (30 ft) from the exterior wall of the mobile home it serves a nd is rated not less man mat required for se1vice equipment in accordance witl1 550.32(C). Grounding at me disconnecting means shall be in accordance with 250.32. (B) Manufactured Home Service Equipment. The manufactured home service equipment shall be permitted to be installed in or on a manufactured h ome, provided that all of the following conditions are met:

(1)

(2)

(B) Mobile Homes and Manufactured Homes. All 120-volt

branch circuits that supply 15- and 20-ampere outlets shall comply with 210.1 2.

(3)

(4) Part III. Services and Feeders 550.30 Distribution System. The mobile home park secondary electrical distribution system to mobile home lots shall be single-phase, 120/ 240 volts, nominal. 550.31 Allowable Demand Factors. Park electrical wiring systems shall b e calculated (at 120/240 volts) on me larger of m e following: (1) (2)

16,000 volt-amperes for each mobile home lot The load calculated in accordance witl1 550.1 8 for the largest typical mobile home mat each lot will accept

It shall be permissible to calculate the feeder or service load in acco1·dance witl1 Table 550.31. No demand facto1· shall be allowed for any other load, except as provided in this Code. 550.32 Service Equipment. (A) Mobile Home Service Equipment. The mobile home servic e equipment shall be located adjacent to the mobile home and not mounted in or on the mobile home. The service

550.32

(5)

(6) (7)

The manufacturer shall include in its written installation instructions information indicating mat the home shall be secured in place by an anchoring system or installed on and secured to a permanent foundation. The installation of the service shall comply with Part I through Part VII of Article 230. Means shall be provided for the connection of a grounding e lectrode conductor to the service equipment and routing it ou tside the structure. Bonding and grounding of the service shall be in accordance witl1 Part I through Part V of Article 250. The manufacturer shall include in its written installation instructions one method of grounding the se1vice equipme nt at me installation site. The instructions shall clearly state mat oilier metl1ods of grounding are found in Article 250. The minimum size grounding electrode conductor shall be specified in me instructions. A warning la bel shall be mounted on or adjacent to me se1vice equipment. The label shall meet m e 1·equirements in 110.21 (B) and shall state me following: WARNING DO NOT PROVIDE ELECTRICAL POWER UNTIL THE GROUNDING ELECTRODE(S) IS INSTALLED AND CONNECTED (SEE INSTALLATION INSTRUCTIONS).

Where the service equipme nt is not installed in or on me unit, me installation shall comply with the other requirements of mis section. (C) Rating. Mobile home se1vice equipme nt shall be rated at

Table 550.31 Demand Factors for Services and Feeders Number of Mobile Homes

2 3 4

5 6 7-9 10-12 13-15 16-21 22-40 41 -60 61 and over 2020 Edition

NATIONAL ELECTRICAL CODE

Demand Factor(%) 100 55 44 39 33 29 28 27 26 25 24 23 22

not less than 100 amperes at 120/ 240 volts, and provisions shall be made for conn ecting a m obile home feeder assembly by a permanent wiring me thod. Power outlets used as mobile h ome se1v ice equipment shall a lso be permitted to contain receptacles rated up to 50 amperes witl1 approp1·iate ove1·cmTent protection. Fifty-ampere receptacles sha ll conform to me config uration shown in Figure 550.lO (C) . I nformational Note: Complete detai ls of Lhe 50-ampere p lug and receptacle configuration can be found in ANSl/ NEMA WD 6-2016, Wiring Deuices - Dimensional S/Jecificalions, Figure 14-50.

(D) Additional Outside Electrical Equipment. Means fo1· connecting a mobile home accessory building or strucmre o r additional electrical equipment located outside a mobile home by a fixed wiring method sha ll be provided in e ither the mobile home service equipment or the local external disconnecting means permitted in 550.32 (A) .

70-479

550.32

ARTICLE 551-RECREATIONAL VEHICLES AND RECREATIONAL VEHICLE PARKS

(E) Additional Receptacles. Receptacles located outside a mobile or manufactured home shall be provided with groundfault circuit-interrupter protection as specified by 210.S(A) . '"There receptacles provide power to a mobile or manufactured home in accordance with 550.10, ground-fault circu itinterrupter protection shall not be required. (F) Mounting Height. Outdoor mobile home disconnecting

means shall be installed so the bottom of the enclosure containing the disconnecting means is not less than 600 mm (2 ft) above finished grade or working platform. Th e disconnecting means shall be installed so that the cente1- of the grip of the operating handle, when in the highest position, is not more than 2 .0 m (6 ft 7 in.) above the finished grade or working platform. (G) Marking. '"There a 125/ 250-volt receptacle is used in mobile home service equipment, the service equipment shall be marked as follows: T URN DISCONNECTING SWITCH OR CIRCUIT BREAKER OFF BEFORE INSERTING OR REMOVING PLUG. PLUG MUST BE FULLY INSERTED OR REMOVED. The marking shall be located on the service equipment adj acent to the receptacle o utlet. 550.33 Feeder. (A) Feeder Conductors. Feeder conductors shall comply with the following: (1)

(2)

Feeder conductors shall consist of either a listed cord, factory installed in accordance with 550.lO(B), or a permanently installed feeder consisting of four insulated, color-coded conductors that shall be identified by the factory or field marking of the conductors in compliance with 310.6. Equipment grounding conductors shall not be identified by stripping the insulation . Feede1- conductors shall be installed in compliance with 250.32(B) .

Exception: An e:xisting feeder installed without an equipment grounding conductor shall be permitted to comply with 250.32(B)(l) Exception No. 1. (B) Feeder Capacity. Mobile home and manufactured home feeder c ircuit conducto1-s shall have a capacity not less than the loads supplied, shall have an ampacity of not less than 100 a mperes, and shall be permitted to be sized in accordance with 310.12.

des to a supply of electricity, a nd the installation of equipment and devices related to electrical installations within a recreational vehicle park. Informational Note: For information on low-voltage systems, refer to NFPA 1192-2018, Stan dard on Recreational Vehicles, and ANSl/RVIA LV-2014, Standard for Low Voltage Systems in Conversion and Recreational Vehicles.

551.2 Definitions. (See Article 100 for additional defin itions.) Air-Conditioning or Comfort-Cooling Equipment. This definition shal l apply only witl1in this article. All of that equipment intended or installed for the purpose of processing the treatment of air so as to control simultaneously or individually its temperature, h umidity, cleanliness, and distribution to meet the requirements of the conditioned space. Appliance, Fixed. This definition shall apply only within this article. An appliance that is fastened or otherwise secured at a specific location .

Camping Trailer. This defin ition shall apply only within this article . A vehicular portable un it mounted on wheels a nd constructed with collapsible partial side walls tha t fold for towing by another vehicle and tmfold at the campsite to provide temporary living quarters for recreational, camping, or travel u se. (See Recreational Vehicle.) Converter. This definition shall apply only within this article. A device that changes electrical energy from one form to another, as from alternating current to d irect current. Dead Front (as applied to switches, circuit breakers, switchboards, and panelboards). This definition shall apply only within this article. Designed, constructed, and installed so that no currentcarrying parts are normally exposed on the front. Discom1ecting Means. This definition shall apply only within this article . The necessary equipment usually consisting of a c ircuit breaker or switch and fuses, and their accessories, located near the point of entrance of supply conductors in a recreational veh icle and intended to constitute the means of cutoff for the supply to that recreational vehicle. Frame. This definition shall apply only within this article.

ARTICLE 551 Recreational Vehicles and Recreational Vehicle Parks Part I. General 551.1 Scope . This article covers the electrical condu ctors and equipment other than low-voltage and automotive vehicle circuits or extensions thereof, installed within 01- on recreational vehicles, the conductors that connect recreational veh i-

70-480

Chassis rail and any welded addition thereto of metal thickness of 1.35 mm (0 .053 in. ) o r greater. Low Voltage. Th is definition shall apply only within this article. An elecu-omotive force rated 24 volts, nominal, or less. Motor Home. This definition shall apply only within this article. A vehicular unit designed to provide temporary living quarters for recreational, camping, or travel use built on or permanently attached to a self-propelled motor vehicle chassis or on a chassis cab or van that is an integral part of the completed ve hicle. (See Recreational Vehicle.)

NATIONAL ELECTRICAL CODE

2020 Edi tion

ARTICLE 551-RECREATIONAL VEHICLES AND RECREATIONAL VEHICLE PARKS

551.20

Power-Supply Assembly. This definition shall apply only within this article.

Truck Camper. Thi.5 definition shall apply only within this article.

The conductors, including ungrounded, grounded, and equipment grounding conductors, the con nectors, attachment plug caps, and all other fittings, grommets, 01- devices installed for the purpose of delivering energy from the source of electrical supply to the distribution panel within the recreational veh icle.

A portable unit constructed to provide temporary living quarters for recreational, travel, or camping use, consisting of a roof, floor, and sides, designed to be loaded onto and unloaded from the bed of a pickup truck. (See Recreational Vehicle.)

Recreational Vehicle. This definition shall apply within this article and throughout the Code.

(A) Not Covered. A recreational vehicle not used for the purposes as defined in 551.2 shall not be required to meet the requirement5 of Part IV pertaining to the number or capacity of circuits required. It shall, however, meet all other applicable requirements of this article if the recreational vehicle is provided with an electrical installation intended to be energized from a 120-volt, 208Y/ 120-volt, or 120/ 240-volt, nominal, ac power-supply system.

A vehicular-type unit primarily designed as temporary living quarters for recreational, camping, or travel use, which either has it5 own motive power or is mounted on or drawn by anothe1- vehicle. lnformarional Note: The basic entities are travel trailer, camping trailer, truck camper, and motor home as referenced in NFPA l 192-2018, Standard on Recreational Vehicles. See 3.3.52, Recreational Vehicle, and A.3.3.52 of NFPA 1192.

Recreational Vehicle Park. within this article.

This definition shall apply only

Any parcel or tract of land under the control of any pe1-son, organization, or governmental entity wherein tvm or more recreational vehicle , recreational park trailer, and/ or other camping sites are offered for use b y the public or members of an organization for overnight stays. Recreational Vehicle Site. within this article.

This definition shall apply only

A specific area within a recreational vehicle park or campground that is set aside for use b y a camping unit. Recreational Vehicle Site Feeder Circuit Conductors. This definition shall apply only with in this article. The conductors from the park service equipment to the recreational vehicle site supply equipment. Recreational Vehicle Site Supply Equipment. This definition shall apply only within this article. The necessary equipm ent, usually a power outlet, consisting of a circuit breaker or switch and fuse and their accessories, located near the point of entrance of supply conductors to a recreational vehicle site and intended to constitute the disconnecting means for the supply to that site. Recreational Vehicle Stand. 'vi thin this article.

This definition shall apply only

That area of a recreational veh icle site intended for the placement of a recreational vehicle . Travel Trailer. This definition shall apply only within this article. A vehicular unit, mounted on wheels, designed to provide temporary living quarters fo1- recreational, camp ing, or travel use, of such size or weight as not to require special highway movement permits when towed by a motorized vehicle, and of gross trailer area less than 30 m 2 (320 ft2 ) . (See Recreational Vehicle.)

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NATIONAL ELECTRICAL CODE

551.4 General Requirements.

(B) Systems. This article covers combination e lectrical systems, generator installations, and 120-volt, 208Y/ 120-volt, or 120/ 240-volt, nominal, systems. Informational Note: For information on low-voltage systems, refer to NFPA I 192-2018, Standard on R ecreational Vehicles, and ANSl/ RVIA 12\1-2011 , Standard for Low Vollage Systems in Conversion and Recreational Vehicles. (C) Labels. Labels required b y Article 551 shall be made of etched, metal-stamped, or embossed brass; stainless steel; plastic laminates not less than 0.13 mm (0.005 in.) thick; or anodized or alclad aluminum not less than 0.5 mm (0.020 in. ) thick 01· the equivalent. Informational Note: For guidance on other labe l criteria used in the recreational vehicle industry, refer lO ANSI Z535.4-2011 , Pmduct Safety Signs and Labels.

Part II. Combination Electrical Systems 551.20 Combination Electrical Systems. (A) General. Vehicle wiring suitable for connection to a battery or de supply source shall be permitted to be connected to a 120-volt source, provided the e ntire wiring system and equipment are rated and installed in full conform ity with Parts I, II, III, IV, and V requirement5 of this article covering 120-volt electrical systems. Circuits fed from ac u-ansformers shall not supply de appliances. (B) Voltage Converters (120-Volt Alternating Current to LowVoltage Direct Current). The 120-volt ac side of the voltage converter shall be wired in full conformity \vith the requiremen ts of Parts I, II, and IV of this a rticle for 120-volt e lectrical systems.

Exception: Converters supplied as an integral part ofa listed appliance shall not be subject to 551. 20(B). All converte1-s and u·ansformers shall be listed fo1· use in recreational vehicles and designed or equipped to provide overtemperature protection. To determine the converter rating, the following percentages sh a ll be applied to the total connected load, including average battery-charging rate, of a ll 12-volt equipment:

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551.20

ARTICLE 551-RECREATIONAL VEHICLES AND RECREATIONAL VEHICLE PARKS

The first 20 amperes ofload at 100 percent plus The second 20 amperes ofload at 50 percent plus All load above 40 amperes at 25 percent .Exception: A low-voltage appliance that is controll.ed by a momentary switch (normally open) that has no means for holding in the cl.osed position 1Jr refrigerators with a 120-volt function shall not be considered as a connected load when determining the required converter rating. Momentarily energized appliances shall be limited to those used to prepare the vehicl.e for occupancy or travel. (C) Bonding Voltage Converter Enclosures. The non-currentcarrying metal enclosure of the voltage converter shall be connected to the frame of the vehicle with a minimum 8 AWG copper conductor. The voltage converter shall be provided with a separate chassis bonding conducto1- that shall not be used as a current-carrying conductor.

(D) Dual-Voltage Fixtures, Including Luminaires or Appliances. Fixtures, including luminaires, or appliances having both 120-volt and low-voltage connections shal l be listed for dual voltage. (E) Autotransformers. Autotransfo1-mei-s shall not be used. (F) Receptacles and Plug Caps. Where a recreational vehicle is equipped with an ac system, a low-voltage system, or both, receptacles and plug caps of the low-voltage system shall differ in configuration from those of the ac system . VVhere a vehicle equipped with a battery or other low-voltage system has an external connection for low-voltage powe1-, the connector shall have a configuration that will not accept ac power.

be of the stranded type and be installed in listed flex ible conduit or listed liquidtight flexible conduit. The point of fi rst termination shall be in one of the fo llowing: ( 1)

Panelboard

(2) Junction box with a blank cover (3)

(4) (5)

Junction box with a receptacle Enclosed transfer switch Receptacle assembly listed in conjunction with the genera tor

The panelboard, enclosed u-ansfer switch, 01- junction box with a receptacle shall be installed with in 450 mm (18 in.) of the point of entry of the supply conductors in to the vehicle . A junction box with a blank cover shall be mounted on the compartment wall inside or outside the compartment; to any part of the generator-supporting structme (but not to the generator); to me vehicle floor on the outside of the vehicle; 01within 450 mm (18 in.) of the point of entry of the supply conductors into the vehicle . A receptacle assembly listed in conjunction with the generator shall be mounted in accordance with its listing. 551.31 Multiple Supply Source. (A) Multiple Supply Sources. Where a multiple supply system consisting of an alternate power source and a power-supply cord is installed, the feeder from the alternate power source shall be protected by an overcurrent protective device . Installation shall be in accordance with 551.30(A), 551.30(B), and 551.40.

(B) Multiple Supply Sources Capacity. The multiple supply sources shall not be required to be of the same capacity.

(A) Mounting. Generators shall be mounted in such a manner as to be effectively bonded to the recreational vehicle chassis.

(C) Alternate Power Sources Exceeding 30 Amperes. If an alternate power source exceeds 30 ampe1-es, 120 volts, nominal, it shall be permissible to wire it as a 120-volt, n ominal, system , a 208Y/120-volt, nominal, system, or a 120/ 240-volt, nominal, system, provided an overcurrent protective device of d1e proper rating is installed in the feeder.

(B) Generator Protection. Equipment shall be installed to ensure that d1e current-carrying conductors from the engine generator and from an outside source are not connected to a vehicle circuit at the same time. Automatic transfer switches in such applications shall be listed for use in one of the following:

(D) Power-Supply Assembly Not Less Than 30 Amperes. The external powe1--supply assembly shall be permitted to be less than the calculated load but not less than 30 amperes and shall have overcurrent protection not greater than the capacity of the external power-supply assembly.

(1)

551.32 Other Sources. Oth er somces of ac power, such as inverters, motor generators, or engine generators, shall be listed for use in recreational ve hicles and shall be installed in accordance with the terms of the listing. Other sources of ac power shal l be wired in full conformity with th e requirements in Parts I , II, ill, IV, and V of this article covering 120-volt electrical systems.

Part III. Other Power Sources 551.30 Generator Installations.

(2)

Emergency systems Optional standby systems

Receptacles u sed as disconnecting means shal l be accessible (as applied to wiring methods) and capable of interrupting their rated current without hazard to the operator. (C) Installation of Storage Batteries and Generators. Storage batteries and internal-combustion-driven generator units (subject to the provisions of d1is Code) shall be seemed in place to avoid d isplacement from vibration and road shock.

(D) Ventilation of Generator Compartments. Compartments accommodating internal-combustion-driven generator units shall be provided with ventilation in accordance with instructions provided by the manufacturer of the generator unit. Informational Note: For generator compartment construction requirements, see NFPA 1192-2018, Standard on Recreational Vehicws.

551.33 Alternate Source Restrictions. Transfer equipment, if not integrnl with the listed power source, shall be installed to ensure that the current-carrying conductors from other sources of ac power and from an outside source are not connected to the vehicle circuit at the same time. Automatic transfer switches in such applications shall be listed for use in one of d1e fo llowing: (1) (2)

Emergency systems Optional standby system s

(E) Supply Conductors. The supply conductors from the engine generator to the first tennination on the vehicle shall 70-482

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ARTICLE 551-RECREATIONAL VEHICLES AND RECREATIONAL VEHICLE PARKS

Part IV. Nominal 120-Volt or 120/ 240-Volt Systems

(3)

551.40 120-Volt or 120/ 240-Volt, Nominal, Systems. (A) General Requirements. The electrical equipment and material of recreational vehicles indicated for connection to a \vising system rated 120 volt~, nominal, 2-wire with equipment grounding conductor, or a wiring system rated 120/ 240 volts, nominal, 3-wire with equipment grounding conductor, shall be listed and installed in accordance with the l'equirements of Parts I, II, III, IV, and V of this article. Electrical equipment connected line-to-line shall have a voltage rating of 208230 volts . (B) Materials and Equipment. Eleco-ical materials, devices, appliances, fittings, and other equipment installed in, intended for use in, 01- attached to the 1-ecreational vehicle shall be listed. All products shall be used on ly in the manner in which they have been tested and found suitable for the intended use. (C) Ground-Fault Circuit-Interrupter Protection. The internal wiring of a recreational vehicle having only one 15- or 20ampere bran ch circuit as permitted in 551.42 (A) and (B) shall have grotmd-fault ci1-cuit-interrupter protection fo1- personnel. The ground-fault circuit interrupter shall be installed at the point where the power supply assembly terminates within the 1-ecreational vehicle . 'i\There a separable cord set is not employed, the ground-fault circuit interrupter shal l be permitted to be an integral part of the attachment plug of the power supply assembly. The ground-fault c ircuit interrupter shall provide protection a lso under the conditions of an open grounded circuit conductor, interchanged circuit conductors, or both.

(D) Reverse Polarity Device. A reverse polarity indi cating device that provides a contin uous visible or audible signal shall be installed in the recreational vehicle in accordance with the installation instructions and shall respond to the reversal of the ungrounded and the grounded conductors in the 120-volt ac system. 551.41 Receptacle Outlets Required. (A) Spacing. Receptacle outlets shall be installed at wall spaces 600 mm (2 ft) wide or more so that no point along the floor line is more than 1.8 m (6 ft), measured horizontally, from an outlet in that space. Exception No. 1: Bath and hallway areas shall not be required to comply with551.41(A). l!,xception No. 2: Wall spaces occupied by kitchen cabinets, wardrobe cabinets, built-in furniture, behind doors that can open fully against a wall su1face, or similar facilities shall not be required Lo comply with 551.41(A). Exception No. 3: Wall spaces in the special transportation area of a recreational vehide designed to transport internal combustion vehicles shall not be required to compl:j with 551.41 (A).

(B) Location. Receptacle outlets shall be installed as follows: ( 1)

(2)

Adjacent to countertops in the kitchen fat least one on each side of the sink if cotmtertops are on each side and are 300 mm (12 in.) or over in width and depth] . Adjacent to the refrigerator and gas range space, except where a gas-fired refrigerator or cooking appliance, requiring no external elecu-ical connection, is facto1y installed.

2020 Edition

NATIONAL ELECTRICAL CODE

(4)

(5)

551.42

Adjacent to countertop spaces of 300 mm (12 in. ) or more in width and depth that can not be reached from a receptacle required in 551.4l(B)(l) b y a cord of 1.8 m (6 ft) without crossing a traffic area, cooking appliance, or sink. Rooftop decks that are accessible from inside the recreational vehicle shall have at least one receptacle installed within the perimeter of the rooftop deck. The receptacle shall not be located more than 1.2 m ( 4 f t) a bove the balcony, deck, or porch surface. T he receptacle sh all comply with the requiremen ts of 406 .9(B) for wet locations. A special ffansportat ion area of recreational vehicl es designed to transport internal combustion engine vehicles shall have at least one receptacle installed.

(C) Ground-Fault Circuit-Interrupter Protection. Where provided, each 125-volt, sing le-phase, 15- or 20-ampere receptacle outlet shall have ground-fault circuit-in terrupter protection for personnel in the following locations: (1) (2)

Adjacent to a bathroom lavatory Where the receptacles are instal led to ser ve the countertop surfaces and are within 1.8 m (6 ft) of any lavato1y or sink

Exception No. 1: Receptacles installed for appliances in dedicated spaces, such as for disposals, refrigerators, and freezers shall not require groundfault circuit-interrupter protection. Exception No. 2: Single receptacles for inte1ior connections of expandable room sections shall not require groundfault cirmit-interrupter protection. Exception No. 3: De-energned receptacles that are within 1.8 m (6 ft) of any sink or lavat01y due to the retraction of the expandable room section shall not require groundfault circuit-interrupter protection. (3) (4)

In the area occupied by a toilet, shower, nib, or any combination thereof On the exterior oftl1e veh icle

Exception: Receptacles that are located inside of an access panel that is installed on the exterior of the vehicle to supply power for an installed appliance shall not be requ:ired to have groundfault circuit-interrupter protection. (5)

In the special u-ansportation area ofa 1-ecreational vehicle that is separated from the living area by a wall

The receptacle outlet sh all be permitted in a listed luminaire. A receptacle outlet sh a ll not be installed in a nib or combination tub-shower com partment. (D) Face-Up Position. A receptacle shall not be installed in a face-up position in any countertop or simila1- horizontal surface.

551.42 Branch Circuits Required. Each recreational vehicle containing an ac elecu-ical system shall contain one of the c ircuit arrangements in 551.42(A) through (D) . (A) One 15-Ampere Circuit. One 15-ampere circuit to supply lights, receptacle outlets, and fixed applia nces. Such rec1-eational vehicles shall be equipped with one 15-ampere switch and fuse or one 15-ampere circuit breaker. (B) One 20-Ampere Circuit. One 20-ampere circuit to supply lights, receptacle ou tie ts, a nd fixed appl ia nces. Such recrea-

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551.42

ARTICLE 551-RECREATIONAL VEHICLES AND RECREATIONAL VEHICLE PARKS

tional vehicles shall be equipped with one 20-ampere switch and fuse or one 20-ampe1-e circuit breakei-. (C) Two to Five 15- or 20-Ampere Circuits. Two to five 15- or 20-ampere circuits to supply lights, receptacle outlets, and fixed appliances shall be permitted. Such recreational veh icles shall be permitted to be equipped with panelboards rated 120 volt maximum or 120/ 240 volt maximum and listed for 30-ampere application supplied by the appropriate power-supply assemblies. Not more than two 120-volt thermostatically controlled appliances shall be installed in such systems unless appliance isolation switching, energy management systems, or similar methods are used. Exception No. 1: Additional 15- or 20-ampere circuits shall be permitted where a listed energy management system rated at 30-ampere maximum is employed within the system. Exception No. 2: Six 15- or 20-ampere circuits shall be pennitted without employing an energy management system, provided that the added sixth circuit serves only the power converte1; and the combined load of all six circuits does not exceed the allowable load that was designed for use by the original five circuits. Informational Note: See 210.23(A) for permissible loads. See 551.45(C) for main disconnect and overcurrem protection requirements.

(D) More Than Five Circuits Without a Listed F.nergy Management System. A 50-ampere, 120/ 208-240-volt power-supply assembly and a minimum 50-ampere-rated panelboard shall be used where six or more circuits are employed. The load distribution shall ensure a reasonable cun-ent balance between phases. 551.43 Branch-Circuit Protection. (A) Rating. The branch-circuit overcurrent devices shall be rated as follows: (1) (2)

(3)

Not more than the cir-cuit conductor·s, and Not more than 150 percent of the rating of a single appliance rated 13.3 amperes or more and supplied by an individual branch c ircuit, but Not more than the overcmrent protection size marked on an air conditioner or other motor-operated appliances

(B) Protection for Smaller Conductors. A 20-ampere fuse or circuit breaker shall be permitted for protection for fixtures, including luminaires, leads, cords, or small appliances, and 14 AWG tap conductm-s, not over 1.8 m (6 ft) long for 1-ecessed luminaires. (C) Fifteen-Ampere Receptacles Considered Protected by 20 Amperes. If more than one receptacle or load is on a branch circuit, 15-ampere receptacles shall be permitted to be protected by a 20-ampere fuse or circuit breaker.

551.44 Power-Supply Assembly. Each 1-ecreational vehicle shall have only one of the main power-supply assemblies covered in 551.44(A) through (D) . (A) Fifteen-Ampere Main Power-Supply Assembly. Recreational vehicles wired in accordance with 551.42(A) shall use a listed 15-ampere or larger main power-supply assembly. (B) Twenty-Ampere Main Power-Supply Assembly. Recreational vehicles wired in accordance with 551.42(B) shall use a listed 20-ampere or larger main power-supply assembly.

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(C) Thirty-Ampere Main Power-Supply Assembly. Recreational vehicles wired in accordance with 551.42(C) shall use a listed 30-ampere or larger main power-supply assembly.

(D) Fifty-Ampere Power-Supply Assembly. Recreational vehicles wired in accordance with 551.42(D) shall use a listed 50ampere, 120/ 208-240-volt main power-supply assembly. 551.45 Panelboard. (A) Listed and Appropriately Rated. A listed and appropriately rated panelboard or other equipment specifically listed for this purpose shall be used. The grounded conductor termination bar shall be insulated from the enclosure as provided in 551.54(C) . An equipment grounding terminal bar shal l be attached inside the enclosure of the panel board. (B) Location. The panelboard shall be installed in a 1-eadily accessible location with the RV in the setup mode. Working clearance for the panelboard with the RV in the setup mode shall be not less than 600 mm (24 in.) wide and 750 mm (30 in.) deep. .Exception No. 1: Whe111 the panelboard cover is exposed to the inside aisle space, one of the working clearance dimensions shall be permitted to be reduced to a minimum of 550 mm (22 in.). A pane/board is considered exposed where the pane/board cover is within 50 mm (2 in.) of the aisle's finished swface or not more than 25 mm ( 1 in.) from the backside of doors that enclose the sf1ace. Exception No. 2: Compartment doors med far access to a generator shall be permitted to be equipped with a locking system.

(C) Dead-Front Type. The panelboarcl shall be of the deadfront type and shall consist of one or more circuit breakers or Type S fuseholde1-s. A main disco1mecting means shall be provided where fuses are used or where more than two circuit breakers are employed. A main overcurrent protective device not exceeding the power-supply assembly rating sha ll be provided where more than two branch circuits are employed. 551.46 Means for Connecting to Power Supply. (A) Assembly. The power-supply assembly or assemblies shall be factory supplied or factory installed and be of one of the types specified herein . (1) Separable. Where a separable power-supply assembly consisting of a cord with a female connector and molded attachment plug cap is provided, the vehicle shall be equip ped with a permanently mounted, flanged surface inlet (male, recessed-type motor-base attachment plug) wired d irectly to the panelboard b y an approved wiring method. The attachment plug cap shall be of a listed type. (2) Permanently Connected. Each power-supply assembly shall be connected directly to the terminals of the panelboard or conductors within a junction box and provided with means to prevent strain from being transmitted to the terminals. The ampacity of the conductors bet\veen each junction box and the terminals of each panelboard shall be at least equal to tl1e ampacity of the power-supply cord. The supply e nd of the assembly shall be equipped with an attachment plug of the type described in 551.46(C). V\There the cord passes through the walls or floors, it shall be protected by means of conduit and bush ings or equivalent. The cord assembly shall have permanent provisions for protection against corrosion and mechanical damage while the vehicle is in transit and while the cord assembly is being stored or removed for use.

NATIONAL ELECTRICAL CODE

2020 Edition

ARTICLE 551-RECREATIONAL VEHICLES AND RECREATIONAL VEHICLE PARKS (B) Cord. The cord exposed usable length shall be measured from the point of entrance to the recreational vehicle or the face of the flanged surface inlet (motor-base attachment plug) to the face of the attachment plug at the supply end. The cor·d exposed usable length, measured to d1e point of enU)' on the vehicle exterior, shall be a minimum of 7.5 m (25 ft) where the point of entrance is at the side of the vehicle or shall be a minimum 9.0 m (30 ft) where the point of en o·ance is at the rear of the vehicle. \'\There the cord entrance into the vehicle is more than 900 mm (3 ft) above the ground, the minimum cord lengths above shall be increased by the vertical distance of the cord enu·ance height5 above 900 mm (3 ft) . Informational Note: See 551.46(E) for location of point of entrance of a power'supply assembly on the recreational vehicle exterior·.

(C) Attachment Plugs. ( 1) Units with One 15-Ampere Branch Circuit. Recreational vehicles having only one 15-ampere branch circuit as permitted by 551.42(A) shall have an attachment plug d1at shall be 2pole, 3-wire grounding type, rated 15 amperes, 125 volts, conforming to the configuration shown in Figure 551.46(C)( l) . Informational Note: Complete details of this configuration can be found in ANSI/ NEMA WD 6-2016, Wiring Devices - Dimensional Sj!ecificalions, Figure 5.1.5.

(2) Units with One 20-Ampere Branch Circuit. Rec reational vehicles having only one 20-ampere branch circuit as permitted in 551.42(B) shall have an attachment plug that shall be 2-pole, 3-wire grounding type, rated 20 amperes, 125 volts, conforming to the con figuration shown in Figure 551.46(C) (1 ) . Informational Note: Complete details of this configuration can be found in ANSl/NEMA WD 6-2016, Wiring Devices - D imensional SjJecificalions, Figure 5.20.

Receptacles

Cap s

@)

@ @

II" w

20-A, 125-V, 2-pole, 3-wire, grounding type

wI

I

125-V, 20-A, 2-pole, 3-wire, grounding type

125-V, 15-A, 2-pole, 3-wire, grounding type

© @ @ @ 0

w

w

I

30-A, 125-V, 2-pole, 3-wire, grounding type

w

x

y

w

50-A, 125/250-V, 3-pole, 4-wire, grounding type

FIGURE 551.46(C)(l ) Configurations for Grounding-Type Receptacles and Attachment P lug Caps Used for Recreational Vehicle Supply Cords and Recreational Vehicle Lots. 2020 Edition

NATIONAL ELECTRICAL CODE

551.46

(3) Units with Two to Five 15- or 20-Ampere Branch Circuits. Recreational vehicles wired in accordance with 551.42(C) sha ll have an attachment plug that shall be 2-pole, 3-wi.re grounding type, rated 30 amperes, 125 volts, conforming to the configuration shown in Figure 551.46(C) (1) intended for use with units rated at 30 amperes, 125 volts. Informational Note: Complete details of d1is configuration can be found in ANSI/ NEMA WD 6-2016, Wiring Devices - Dinumsional Sj)(icijications, Figure TI.

(4) Units with 50-Ampere Power-Supply Assembly. Rec r·eational vehicles having a power-supply assembly rated 50 amperes as permitted by 551.42 (D) shall have a 3-pole, 4wire grounding-type attachment plug rnted 50 amperes, 125/250 volts, conforming to the configuration shown in Figure 551.46 (C) (1 ) . Informational Note: Complete detai ls of this configuration can be found in ANSI/ NEMA WD 6-2016, Wiring De11ices - Dimensional Specifications, Figure 14.50.

(D) Labeling at Electrical Entrance. Each recreational vehicle shall have a safety labe l with the sig nal word WARNING in minimum 6-mm (!l.1-in.) h igh letters and body text in minimum 3-mm ( Ys-in.) high letters on a contrasting background. The safety label shall be affixed to the exterior skin, at or near the point of enu·ance of the power-supply cord(s), and shall read, using one of the following warnings, as appropriate:

WARNING THIS CONNECTION IS FOR 110-125-VOLT AC, 60 HZ, _ _ AMPERE SUPPLY. DO NOT EXCEED CIRCUIT RATING. EXCEEDING THE CIRCUIT RATING CAN CAUSE A FIRE AND RESULT IN DEATH OR SERIOUS INJURY. or WARNING THIS CONNECTION IS FOR 208Y/ 120NOLT or 120/ 240-VOLT AC, 3-POLE, 4-WlRE, 60 HZ, _ _ AMPERE SUPPLY. DO NOT EXCEED CIRCUIT RATING. EXCEEDING THE CIRCU IT RATING CAN CAUSE A FIRE AND RESULT IN DEATH OR SERIOUS INJURY. The correct ampere rating shall be marked in the blank space. (E) Location. The point of entrance of a power-supply assembly shal l be located within 4.5 m (15 ft) of the rear, on d1e left (road) side or at the rear, left of d1e longitudinal center of the vehicle, within 450 mm (18 in .) ofd1e outside wall . Exception No. 1: A recreational vehicle equipped with only a listed fle:xible drain system or a side-vent drain system shall be permitted to have the electrical point of entrance located on either side, provided the drain(s) for the plumbing system is (are) located on the same side. Exception No. 2: A recreational vehicle shall be permitted to have the electrical point of entrance located more than 4.5 m (15 ft) from the rem: \/Vliem this occurs, the distance beyond the 4.5-m ( 15ft) dimension shall be added to the cord's minimum length as specified in 55 J.46(B). Exception No. 3: Recreational vehicles designed for transporting livestock shall be permitted to have the electrical point of entrance located on either side ar the front.

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551.47

ARTICLE 551-RECREATIONAL VEHICLES AND RECREATIONAL VEHICLE PARKS

551.4 7 Wiring Methods. (A) Wiring Systems. Cables and raceways installed in accordance with Articles 320, 322, 330 through 340, 342 through 362, 386, and 388 shall be permitted in accordance with their applicable article, except as otherwise specified in this article. An equipment grounding means shall be provided in accordance with 250.118. (B) Conduit and Tubing. Where 1-igid metal conduit or intermediate metal conduit is terminated at an enclostu-e with a locknut and bushing connection, two lockouts shall be provided, one inside and one outside of the enclosure . All cut ends of conduit and tubing shall be reamed or otherwise finished to remove rough edges. (C) Nonmetallic Boxes. Nonmetallic boxes shall be acceptable only with nonmetallic-sheathed cable or nonmetallic raceways.

(D) Boxes. In walls and ceilings constructed of wood or other combustible material, boxes and fittings shall be flush with the finished surface or project therefrom. (E) Mounting. Wall and ceiling boxes shall be mounted in acco1-dance with Article 314. Exception No. 1: Snap-in-type boxes or boxes provided with special wall or ceiling brackets that securely fasten boxes in wa!L5 or ceilings shall be permitted. J!.'xception No. 2: A wooden plate providing a 38-rmn ( 1 1/z-in.) minimum width backing around the box and of a thickness of 13 mm (1!i in.) or greater (actual) attached directly to the wall panel shall be considered as approved means for mounting outlet boxes. (F) Raceway and Cable Continuity. Raceways and cable sheaths shall be continuous between boxes and other enclosures.

(G) Protected. Metal-clad, Type AC, or nonmetallic-sheathed cables and electrical nonmetallic tubing shall be permitted to pass through the centers of the wide side of 2 by 4 wood studs . However, they shall be protected where they pass through 2 b y 2 wood studs or at other wood studs or frames where the cable or tubing would be less than 32 mm (1 Y., in.) from the inside or outside surface . Steel plates on each side of the cable or tubing or a steel tube, with not less than 1.35 mm (0.053 in. ) wall thickness, shall be installed to protect the cable or tubing. These plates or tubes shall be securely held in place. vVhere nonmetallic-sheathed cables pass through punched, cut, or drilled slots or holes in metal members, the cable shall be protected by bushings or grommets securely fastened in the opening prior to installation of the cable . (H) Bends. No bend shall have a radius of less than five ti mes the cable diameter. (I) Cable Supports. Where connected with cable connectors or clamps, cables shall be seemed and supported within 300 mm (12 in.) of outlet boxes, panelboards, and splice boxes on appliances. Suppo1-ts and securing shall be provided at intervals not exceeding 1.4 m (4!0 ft) at other places. (J) Nonmetallic Box Without Cable Clamps. Nonmetallicsheathed cables shall be secured and supported within 200 mm (8 in.) of a nonmetallic outlet box without cable clamps. vVhere wiring devices with integral enclosures a1-e employed with a loop of exu-a cable to permit future replacement of the

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device, the cable loop shall be considered as an integral ponion of the device. (K) Physical Damage. V\fhere subject to physical damage, exposed nonmetallic cable shall be protected b y covering boards, guard su-ips, raceways, 01- other means. (L) Receptacle Faceplates. Metal faceplates shall comply with

406.5(A) . Nonmetall ic faceplates shall comply with 406.5(C) . (M) Metal Faceplates Grounded. Metal faceplates shall be installed in compliance with 404.9(B) a nd 404.6(B) . (N) Moisture or Physical Damage. \.\There outdoor o r underchassis wiring is 120 volts, nominal, or over and is exposed to moisture or physical damage, the wiring shall be protected by rigid metal conduit, by intermediate metal conduit, or by elecu-ical metallic tubing, rigid nonmetallic conduit, or Type MI cable, that is closely routed against frames and equipment enclosures or other raceway or cable identified for the application. (0) Component Interconnections. Fittings and

connectors tl1at are intended to be concealed at the time of assembly shall be listed and identified for the interconnection of building components. Such fittings and connectors shall be equal to the wiring method employed in insulation, temperature rise, and fault-cmTent withstanding and shall be capable of enduring the vibration and shock occurring in recreational vehicles. (P) Method of Connecting Expandable Units. The method of connecting expandable unit5 to the main body of the vehicle shall comply with 551.47(P)(I) or (P)(2) .

(I) Cord-and-Plug-Connected. Cord-and-plug connections shall comply with 551.47(P)(l)(a) through (P)(l)(d) . (a) That portion ofa branch circuit that is installed in an expandable unit shall be permitted to be connected to the po1-tion of the branch circuit in the main body of the vehicle by means of an attachment plug and cord Listed for hard usage. The cord and its connections shall comply with Part I and Part II, a5 applicable, of Article 400 and shall be considered as a permitted use under 400.10. V\fhere the attachment plug and cord are located within the ve hicle 's interior, use of plastic tl1ermoset or elastomer parallel cord Type SPT-3, SP-3, or SPE shall be permitted. (b ) V\fhere the receptacle provided for connection of the cord to the main circuit is located on the outside of the veh icle, it shall be protected with a ground-fault circuit interrupter for personnel and be listed for wet locations. A cord located on the out~ide of a vehicle shall be identified for outdoor use. (c) Unless removable or stored witl1in tl1e vehicle interior, the cord assembly shall have permanent provisions for protection against coITosion and mechanical damage while the vehicle is in transit. (d) The attachment plug and cord shall be installed so as not to permit exposed live attachment pl ug pins. (2) Direct Wired. That portion of a branch c ircuit that is instal led in an expandable unit shall be permitted to be connected to the portion of the branch c ircuit in the main body of the vehicle by means of flexible cord installed in accordance with 551.47(P) (2) (a) through (P)(2) (e) or other approved wiring method. (a) The flexible cord shall be Listed for hard usage and for use in wet locations. (b) The flexible co1-d shall be permitted to be exposed on the underside of the vehicle.

NATIONAL ELECTRICAL CODE

2020 Edition

ARTICLE 551-RECREATIONAL VEHICLES AND RECREATIONAL VEHICLE PARKS (c) The flexible cord shall be permitted to pass through the interior of a wall or floor assembly 01- both a maximmn concealed length of 600 mm (24 in. ) before terminating at an outlet or junction box. (d) \.\There concealed, the flexible cord shall be installed in nonflexible conduit or tubing that is continuous from the outlet or junction box inside the recreational vehicle to a weatherproof outlet box, junction box, or strain relief fitting listed for use in wet locations that is located on the underside of the recreational veh icle. The outer jacket of the flexible cord shall be continuous into the outlet or junction box. (e) Where the flexible cord passes through the floor to an exposed area inside of the recreational veh icle, it shall be protected by means of conduit and bushings or equivalent.

(3)

(4)

or WARNING GENERATOR ONLY INSTALL A GENERATOR LISTED SPECIFICALLY FOR RV USE HAVING OVERCURRENT PROTECTION RATED 120-240-VOLT AC, 60 HZ, AMPERES MAXIMUM.

(Q) Prewiring for Air-Conditioning Installation. Prewiring installed for the purpose of facilitating future air-conditioning installation shall comply witl1 the applicable portions of this article and the following:

(2)

(3)

An overcurrent protective device with a rating compatible with the c ircuit conductors shall be installed in the panelboard and wiring connections comp leted. The load end of the circu it shall terminate in a junction box vvith a blank cover or otl1er listed enclosure. Where a junction b ox with a blank cover is used, the free ends of the conductors shall be adequately capped or taped. A safety label with the signal word WARNING in minimum ~mm (Y.;-in.) high letters and body text in minimum 3-mm (\IS-in .) high letters on a contrasting background shall be affixed on or adjacent to the junction box and shall read as follows:

WARNING AIR-CONDITIONING CIRCUIT. THIS CONNECTION IS FOR AIR CONDITIONERS RATED 110- 125-VOLT AC, 60 HZ, AMPERES MAXIMUM. DO NOT EXCEED CIRCUIT RATING. EXCEEDING THE CIRCUIT RATING MAY CAUSE A FIRE AND RESULT IN DEATH OR SERIOUS INJURY

(4)

An ampere rating, not to exceed 80 percent of the circuit rating, shall be legibly marked in the blank space. The circuit shall se1-ve no other purpose.

(R) Prewiring for Generator Installation. Prewiring installed for the purpose of facilitating future generator installation shall comply with the other applicable portions of this article and the following: (1)

Circuit conducto1-s shall be appropriately sized in relation to the anticipated load as stated on the label required in (R) (4) .

(2)

\.\Th ere jtmction boxes are utilized at e ither of the circuit originating or terminus points, free ends of the conductors shall be adequately capped or taped.

2020 Edition

NATIONAL ELECTRICAL CODE

Where devices su ch as receptacle outlet, transfer switc h, and so fortl1, are installed, the installation shall be complete, including circuit conductor conne ctions. A safety label with the signal word WARNING in minimum ~mm (V.1-in. ) high letters and body text in minimum 3-mm (\IS-in. ) high le tters on a conu-asting background shall be affixed on the cover of each junction box containing incomplete circuitry and shall read, using one of the following warnings, as appropriate: WARNING GENERATOR ONLY INSTALL A GENERATOR LISTED SPECIFICALLY FOR RV USE HAVING OVERCURRENT PROTECTION RATED 110-125-VOLT AC, 60 HZ, _ _ AMPERES MAXIMUM.

Where subject to physical damage, the flexible cord shall be protected with RMC, IMC, Schedule 80 PVC, reinforced thermosetting resin conduit (ITTRC) listed fo1- exposure to physical damage, or other approved means and shall extend at least 150 mm (6 in.) above the floor. A means shall be provided to secure the flexible cord whe1-e it enters the recreational vehicle.

(l )

551.49

The correct ampere rating sha ll be legibly marked in the blank space . (S) Prewiring for Other Circuits. Prewiring installed for the purpose of installing other appliances or devices shall comply with the applicable portions of this article and the fo llowing: (1)

(2)

(3)

An overcurrent protection device with a rating compati-

ble with the c ircuit conductm-s sha ll b e installed in the panelboard with wiring connections completed. The load end of the circuit s hall terminate in a junction box with a bla nk cover or a device listed for tl1e purpose. \.\There a junction box with blank cover is used, the free ends of the conductors shall be adequately capped or taped. A safety la bel with the signal word WARNING in minimum ~mm ( V.1-in.) high letters and body text in minimum 3-mm (Ys-in. ) hig h letters on a contrasti ng background shall be affixed on or adjacent to tl1e jtmction box or device listed for the purpose and shall read as follows: WARNING THIS CONNECTION IS FOR RATED VOLT AC, 60 HZ, _ _ AMPERES MAXIMUM. DO NOT EXCEED CIRCUIT RATING. EXCEEDING THE CIRCUIT RATING MAY CAUSE A FIRE AND RESULT IN DEATH OR SERIOUS INJURY.

An ampere rating not to exceed 80 percent of the c ircuit rating shall be legibly marked in the blank space. 551.48 Conductors and Boxes. The maximum number of conductors permitted in boxes shall be in accordance with 3 14.1 6. 551.49 Grounded Conductors. The identification of grounded conductors shall be in accordance with 200 .6.

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551.50

ARTICLE 551-RECREATIONAL VEHICLES AND RECREATIONAL VEHICLE PARKS

551.50 Connection of Terminals and Splices. Conductor splices and connections at terminals shall be in acco1-dance with 110.14. 551.51 Switches. (A) Rating. Switches shall 551.51 (A) ( l) and (A) (2) .

be

rated

111

accordance with

(1) Lighting Circuits. For lighting circuits, switc hes shal.l be rated not less than 10 amperes, 120-125 volts and in no case less than the connected load.

forth, shall be effectively bonded to the grounding terminals or enclosure of the panelboard. (B) Equipment Grounding and Bonding Conductors. Bare wires, insulated wire with an outer finish that is green or green with one 01- more yellow stripes, shall be used for equipment grounding or bonding conductors only.

(C) Grounding of Electrical Equipment. Grounding of elecn-ical equipment shall be accomplished by one or more of the following methods: (1)

(2) Motors or Other Loads. Switches for motors or other loads shall comply with 404.1 4. (B) Location. Switches shall not be installed within wet locations in tub or shower spaces unless installed as part of a listed tub or shower assembly.

(2)

551.52 Receptacles. All receptacle outlets shall be of the grounding type and installed in accordance with 406.4 and 210.21.

(3)

551.53 Luminaires and Other Equipment. (A) General. Any combustible wall or ceiling finish exposed benveen the edge of a canopy or pan of a luminaire or ceilingsuspended (paddle) fan and the outlet box shall be covered vvith noncombustible material. (B) Shower Luminaires. lf a luminaire is provided over a bathtub or in a shower stall, it shall be of the enclosed and gasketed type and listed for the type of installation, and it shall be g1-ound-faul t circuit-interrupte1- protected. (C) Outdoor Outlets, Luminaires, Air-Cooling Equipment, and So On. Outdoor luminaires and other equipment shall be listed for outdoor use .

551.54 Grounding. (See also 551.56 on bonding of noncurrent-carrying metal parts. ) (A) Power-Supply Grounding. The equipment grounding conductor in the supply cord or feeder shall be connected to the equipment grounding bus or other approved equipment grounding means in tl1e panelboard. (B) Panelboard. The panelboard shall have an equipment grounding bus with terminals for all equipment grounding conductors or other approved equipment grounding means. (C) Insulated Grounded Conductor (Neutral Conductor). The grounded circuit conductor (neutral conductor) shal l be insulated from the equipment grounding conductors and from equipment enclosures and other grounded parts. The grounded circuit conductor (neutral conductor) terminals in the panelboard and in ranges, clothes dryers, counter-mounted cooking units, and wall-mounted ovens shall be insulated from the equipment enclosure. Bonding screws, sn·aps, or buses in the panelboard or in appliances shall be removed and discarded. Connection of electric ranges and electric clothes dryers utilizing a grounded conductor, if cord-connected, shall be made with +conductor cord and 3-pole, 4-wire grounding-type plug caps and receptacles.

551.55 Interior Equipment Grounding. (A) Exposed Metal Parts. In the electrical system, a ll exposed metal parts, enclosures, frames, luminaire canopies, and so

70-488

Connection of metal raceway, the sheath of Type MC and Type MI cable where the sheath is identified for grounding, or the armor of Type AC cable to metal enclosures. A connection benveen the one or more equipment grounding conductors and a metal enclostu-e by means of a grounding screw, which shall be used for no other purpose, or a listed grounding devi ce. The equipment grounding conductor in nonmetallicsheathed cable shall be permitted to be secured under a screw threaded into the luminaire canopy other than a mounting screw or cover screw, or attached to a listed grounding means (plate) in a nonmetallic outlet box for luminaire mounting. [Grotmding means shall also be permitted for luminaire attachment screws.]

(D) Grounding Connection in Nonmetallic Box. A connection between the one or rno1-e equipment grounding conductors brought into a nonmetallic outlet box shall be so arranged tl1at a connection of the equipment grounding conductor can be made to any fitting 01· device in that box that requires grounding. (E) Grounding Continuity. '"' here more than one equipment grounding or bonding conductor of a branch circuit enters a box, all such conductors shall be connected together using a method specified in 250.8, and the arrangement shall be such that the disconnection or removal of a receptacle, luminaire, or other device fed from tl1e box will not interfere with or interrupt the grounding continuity.

(F) Cord-Connected Appliances. Cord-connected appliances, such as washing machines, clothes dryers, refrigerators, and the elecn-ical system of gas ranges, and so forth, shall be grounded by means of an approved cord with equipment grounding conductor and grounding-type attachment plug.

551.56 Bonding of Non-Current-Carrying Metal Parts. (A) Required Bonding. All exposed non-curren t-carryi ng metal parts that are likely to beco me e nergized shall be effectively bonded to the grounding terminal or enclosure of the panelboard. (B) Bonding Chassis. A bonding conductor shall be connected between any panelboard and an accessible terminal on the chassis. Bonding terminations shall be suitable fm the enviromen tin which the condu ctors and terminations are installed. Exception: Any recreational vehicle that emp!.oys a unitized metal chassis-frame construction to which the panelboard is securely fastened with a bolt(s) and nut(s) or by wet.ding oniveting shall be considered to be bonded.

(C) Bonding Conductor Requirements. Grounding terminals shall be of the solderless type and listed as pressure terminal connectors recognized for the wire size used. The bonding

NATIONAL ELECTRICAL CODE

2020 Edition

ARTICLE 551-RECREATIONAL VEHICLES AND RECREATIONAL VEHICLE PARKS

551.72

conductor shall be solid or stranded, insulated or bare , and shall be 8 AWG copper minimum, or equal.

vehicl e site electrical equipment, shall not be required tampe1--resistant in acco1-dance with 406.12.

(D) Metallic Roof and Exterior Bonding. The metal roof and exterior covering shall be considered bonded where both of the following conditions apply:

(B) 30-Ampere. A minimum of 70 percent of all recreational vehicle sites with elecu-ical supply shall each b e equipped with a 30-ampere, 125-volt receptacle confo1-ming to F igure 55 l.46(C)(l) . This supply shall be permitted to include additional receptacle configurations conforming to 551.81. The remainder of all recreational vehicle sites with e lecu·ical supply shall be equipped with one or more of the receptacle configurations conforming to 551.81.

(1)

(2)

The metal panels overlap one another and are securely attached to the wood 01- metal frame parts by metal fasteners. The lower panel of the metal exterior covering is secured by metal fasteners at each cross member of the chassis, or the lower panel is connected to the chassis by a metal strap.

(E) Gas, Water, and Waste Pipe Bonding. The gas, water, and waste pipes shall be considered grounded if they are bonded to the chassis. (F) Furnace and Metal Air Duct Bonding. Furnace and metal circulating air ducts shall be bonded.

551.57 Appliance Accessibility and Fastening. Every appliance shall be accessible for inspection, service, 1-epair, and replacement without removal of permanent consu-uction. Means shall be provided to securely fasten appliances in place when the r·ecreational vehicle is in transit.

Part V. Factory Tests 551.60 Factory Tests (Electrical). Eac h recreational vehicle designed with a 120-volt or a 120/ 240-volt electrical system shall withstand the applied voltage without electrical breakdown of a I -minute, 900-volt ac or 1280-volt de dielecu-ic strength test, or a I-second, 1080-volt ac or 1530-volt de dielectric strength test, with all switches closed, beuveen ungrounded and grounded conductors and the recreational vehicle ground. During the test, all switches and other controls shall be in the "on" position. Fixtures, including luminaires and permanently installed appliances, shall not be required to withstand this test. The test shall be performed after branch circuits are complete prior to ene1-gizing the system and again after a ll outer coverings and cabinetry have been secured. The dielectric test shall be performed in a ccordance with the test equipment manufacturer's written instructions. Each recreational vehicle shall be subjected to all of the following: (1) (2) (3) (4)

A continuity test to ensure that all metal parts are properly bonded Operational tests to demonstrate that all equipment is properly connected and in working order Polarity checks to determine that connections have been properly made GFCI test to demonstrate that the ground fault protection device (s) installed on the recreational vehicle are operating properly

Part VI. Recreational Vehicle Parks 551.71 Type Receptacles Provided. (A) 20-Ampere. Every recreational veh icle site with electrical supply shall be equipped with recreational vehicle site supply equipment with at least one 20-ampere, 125-volt weatherresistant receptacle. This receptacle, when used in recreational

2020 Edition

NATIONAL ELECTRICAL CODE

to

be

(C) 50-Ampere. A minimum of 20 percent of existing and 40 percent of all new recreational veh icle sites, with e lectrical supply, shall each be equipped with a 50-ampere, 125/250-volt receptacle conforming to d1e configtu-ation as ide ntified in Figure 551.46(C)( l ) . Every recreational vehicle site equipped with a 50-ampere receptacle shall a lso be equipped with a 30ampere, 125-volt receptacle conforming to Figure 551.46(C)(l) . These elecu·ical supplies shall be perm itted to include additional receptacles that have con fig urations in accordance with 551.81. Informational Note: The percentage of 50 ampere sites required by 551.71 could be inadequate for seasonal recreational vehicle sites sen~ng a higher percentage of recreational vehicles with 50-ampere electrical systems. In that type of recreational vehicle park, the percentage of 50-ampere sites could approach 100 percent.

(D) Tent Sites. Dedicated tent sites with a 15- or 20-ampere electrical supply shall be permitted to be excluded when determining the percentage of recreational vehicle sites wiili 30- 01· 50-ampere receptacles. (E) Additional Receptacles. Additional receptacles sha ll be permitted for the connection of electrical equipment outside the recreational veh icle within d1e recreational vehicle park. (F) GFCI Protection. All 125-volt, single-phase, 15- and 20-ampere receptacles sha ll have listed ground-fault ci1-cuitinterrupter protection for personnel. T he GFCT devices used in RV site elecu·ical equipment shall not be required to be weather 01· tamper resistant in accordance with 406.9 and 406.1 2. Informational Note: The percentage of 50 ampere sites required by 551.7 l could be inadequate for seasonal recreational vehicle sites serving a higher percentage of recreational vehicles "~th 50 ampere e lectrical systems. In that type of recreational vehicle park, d1e percentage of 50 ampere sites could approach 100 percent.

551.72 Distribution System. (A) Systems. Distribution systems shall provide the voltage and have a capacity for the receptacles provided in th e recreati onal vehicle (RV) site supply equipment as calculated according to 551.73 and shall have a n ampacit:y not less than 30 amperes. Systems permitted include 120 volts, 1-phase; 120/ 240 volts, 1phase; and 120/ 208 volt5, 1-phase. (B) Three-Phase Systems. Feede rs from 208Y/ 120-volt, 3phase systems shall be permitted to include two ungrounded conductors and shall include one grounded conductor and one equipment grounding conductor. So far as practicable, the loads shall be equally distributed on d1e 3-phase syste m.

70-489

551.72

ARTICLE 551-RECREATIONAL VEHICLES AND RECREATIONAL VEHICLE PARKS

(C) Receptacles. Receptacles rated at 50 amperes shall be supplied from a b ranch circuit of the voltage class and rating of the receptacle. Other recreational vehicle sites with 125-volt, 20- and 30-ampere receptacles shall be permitted to be derived from any grounded distribution system that supplies 120-volt, single-phase power. The neutral conductors shall not be reduced in size below the size of the ungrounded condu ctors for the site disn-ibution.

551.74 Overcurrent Protection. Overcurrent protection shall be provided in accordance with Article 240.

(D) Neutral Conductors. Neutral conductors shall be permitted to be reduced in size below the minimum required size of the w1grounded conductors for 240-volt, line-to-line, permanently connected loads only.

(A) Grounding Electrode. Power outlets or recreational ve hicle site supply equipment, other than those used as service equipment, shall not be required to have a grounding electrode. An auxiliary grounding electrode(s) in accordance with 250.54 shall be pennitted to be installed.

Informational Note: Due to the long circuit lengths typical in most recreational vehicle parks, feeder conductor sizes found in the ampacicy cables of Article 310 may be inadequate to maintain the voltage regulation suggested in 215.2(A) (1) Informational Note No. 2 . Total circuit vo ltage drop is a sum of the voltage drops of each serial circuit segment, where the load for each segment is calculated using the load that segment sees and the demand factors shown in Table 551. 73(A).

(E) Connected Devices. The use of autotransformers shall not be permitted. The use of listed surge protective devices sh all be permitted. (F) Connection to Recreational Vehicle Site Equipment. Each recreational vehicle shall be powered by only one 30-ampere or one 50-ampere external power supply cord. Informational Note: The requirement in 551.72(F) does not preclude the use of the 15- or 20-ampere receptacle convenience outlet on t11e recreational vehicle supply equipment.

551.73 Calculated Load. (A) Basis of Calculations. El ectrical services and feeders shall be calculated on the b asis of not less than 12,000 volt-amperes per site equipped with 50-ampere, 208Y/ 120 or 120/ 240-volt supply facilities; 3600 volt-amperes per site equipped with both 20-ampere and 30-ampere supply fac ilities; 2400 volt-amperes per site equipped with only 20-ampere supply facilities; and 600 volt-amperes per site equipped with only 20-ampere supply facilities that are dedicated to tent sites. The demand factors set fortl1 in Table 551.73(A) shall be the minimum a llowable demand factors that shall be permitted in calculating load for service and feeders. ·where the electrical supply for a recreational veh icle site has more than one receptacle, the calculated load shall be calculated only for the highest rated receptacle. '1\lhere the electrical supply is in a location that serves two recreational vehicles, the equipment for both sites shal l comply with 551.77, and the calculated load shall only be calculated for the t:\110 receptacles with the highest rating. (B) Demand Factors. The demand factor for a g iven number of sites shall apply to all sites indicated. For example, 20 sites calculated at 45 percent of 3600 volt-amperes results in a permissible demand of 1620 volt-amperes per site or a total of 32,400 volt-amperes for 20 sites. Informational Note: These demand factors may be inadequate in areas of extreme hot or cold temperature with loaded circuits for heating or air conditioning.

Loads for other amenities such as, but not limited to, service buildings, recreational buildings, and swimming pools shall be calculated separntely and then be added to the value calculated

for the recreational vehicle sites where they are all s upplied by a common service .

551.76 Grounding ment.

(B) Exposed Non-Current-Carrying Metal Parts. Exposed non-current-carrying metal parts of fixed equipment, metal boxes, cabinets, and fittings that are not elecu-ically connected to grounded equipment shall be grounded by an equipment grounding conductor run with the circuit conductors from the service equipment or from the transformer of a secondary distribution system . Equipment grounding conductors shall be sized in accordance with 250 .1 22 and shall be permitted to be spliced by listed means.

The arrangement of equipment g rounding connection s shall be such that the disconnection or removal of a receptacle 01- other device will not interfere with, or interrupt, the grounding continuity. (C) Secondary Distribution System. Each secondary distribution system shall be grounded at the transformer. (D) Grounded Conductor Not to Be Used as an Equipment Ground. The grounded conductor shall not be used as an equipment grounding conductor for reo-eational vehicles or equipment witl1in the recreational vehicle park. (E) No Connection on the Load Side. No connection to a grounding e lecu-ode shall be made to the grounded conductoion the load side of tl1e service disconnecting means except as covered in 250.30(A) for separately derived system s, and 250.32(B) Exception No. 1 for separate buildings. 551.77 Recreational Vehicle Site Supply Equipment. (A) Location. '1\lhere provided on back-in sites, the recreational vehicle site electrical supply equipment shall be located Table 551.73(A) Demand Factors for Site Feeders and ServiceEntrance Conductors for Park Sites Number of Recreational Vehicle Sites l

2 3

Demand Factor (%)

lOO 90

4

80 75

5

65

6 7-9

55

10-12 13-15 16-18 19-21 22-24

25- 35 36 plus

70-490

Recreational Vehicle Site Supply Equip-

60 50

48 47 45 43 42 41

NATIONAL ELECTRICAL CODE

2020 Edi tion

552.5

ARTICLE 552 - PARK TRAILERS on the left (road) side of the parked vehicle, on a line that i.~ 1.5 m to 2.1 m (5 ft to 7 ft) from the left edge (driver's side of the parked RV) of the stand and shall be located at any point on this line from the rear of the stand to 4.5 m (15 ft) fotward of the rear of the stand. For pull-through sites, the electrical supply equipment shall be permitted to be located at any point along the line that is 1.5 m to 2.1 m (5 ft to 7 ft) from the left edge (drive1·'s side of the parked RV) from 4.9 m (16 ft) forward of the rear of the stand to the center point between the two roads that gives access to and egress from the puU-tlu·ough sites.

elecu-ical metallic n ibing with supplementary corrosion p rotection, rigid polyvinyl chloride conduit (PVC), norunetallic underground conduit \vi th conductors (NUCC), high density polyethylene conduit (HDPE), reinforced thermosetting resin conduit (RTRC), liquidtight flex ible nonmetalli c conduit, liquidtight flexible metal condui t, or other approved raceways or enclosures. v\lhere subject to physical damage, the conducto1·s or cables shall be protected by rigid metal conduit, intermediate metal conduit, Schedule 80 PVC conduit, or RTRC listed for exposure to physical damage . All such protection shall extend at least 450 mm (18 in. ) into the trench from finished grade.

The left edge (driver's side of the parked RV) of the stand shall be marked.

Informational Note: See 300.5 and Article 340 for conductors or Type UF cable used underground or in direCL burial in earth.

(B) Disconnecting Means. A disconnecting S\vitch or circuit breaker shall be provided in the site supply equipment for disconnecting the power supply to the recreational vehicle.

551.81 Receptacles. A receptacle to supply e lectric power to a recreational vehicle shall be one of the configurations shown in Figure 551.46(C)(l) in the fo llO\ving ratings:

(C) Access. AU site supply equipment shall be accessible by an unobstructed enu-ance or passageway not less than 600 mm (2 ft) wide and 2.0 m (6 ft 6 in .) high.

(1)

(D) Mounting Height. Site supply equipment shall be located

(3)

not less than 600 mm (2 ft) or more than 2.0 m (6 ft 6 in.) above the ground. (E) Working Space. Sufficient space shall be provided and maintained about all elecu-ical equipment to permit ready and safe operation, in accordance with 110.26.

(2)

50-ampere 125/ 250-volt, 50-ampere, 3-pole, 4-\vire grounding type for 120/ 240-volt systems 30-ampere - 12!>-volt, 30-ampere, 2-pole, 3-\vire grounding type for 120-volt systems 20-ampere - 12!>-volt, 20-ampere, 2-pole, 3-\vire grounding type for 120-volt systems Informational Note: Complete details of these configurations

can be found in ANSI / NElVIA v\ID 6-2016, Wiring Devices Dimensional :Sjieciftcicalions, Figures 14-50, TT, and 5-20.

(F) Marking. vVhere the site supply equipment contains a 125/ 250-volt receptacle, the equipment shall be marked as follows: "Turn disconnecting switch or circuit breaker off before inserting or 1·emoving plug. Plug must be fully inserted or removed." T he marking shall be located on the equipment adjacent to the receptacle outlet.

ARTICLE552 Park Trailers

551.78 Protection of Outdoor Equipment. (A) Wet Locations. All switches, circuit breakers, receptacles, control equipment, and metering devices located in wet locations shall be weatherproof. (B) Meters. If secondary meters are installed, meter sockets \vithout meters installed shall be blanked off \vith an approved blanking plate. 551.79 Clearance for Overhead Conductors. Open conductors of not over 1000 volts, nominal, shall have a vertical clearance of not less than 5.5 m (18 ft) and a horizontal clearance of not less than 900 mm (3 ft) in all areas subject to recreational vehicle movement. In all other areas, clearances shall conform to 225.1 8 and 225.19. Informational Note: For clearances of conductors over 600 volts, nominal, see 225.60 and 225.61.

551.80 Underground Service, Feeder, Branch-Circuit, and Recreational Vehicle Site Feeder-Circuit Conductors. (A) Ge neral. All direct-bmial conductors, including the equipment grounding conductor if of aluminum, shall be insulated and identified for the use. AU conductors shall be continuous from equipment to equipment. All sp lices and taps shall be made in approved jw1ction boxes or by use of listed material. (B) Protection Against Physical Damage. Direct-buried conducto1·s and cables entering or leaving a u·ench shall be protected by rigid metal conduit, intermediate metal conduit,

2020 Edition

NATIONAL ELECTRICAL CODE

Part I. General 552.1 Scope. The provisions of this article cover the e lecu-ical conductors and equipment installed \vithin or on park u-ailers not covered fully under Articles 550 and 551. 552.2 Definition. The defin ition in this section shall apply within this article and throughout the Code. (See Articles 100, 550, a nd 551 for additional defi nitions.) Park Trailer. A unit that is built on a single chassis mounted on wheels and has a gross trailer area not exceeding 37 m 2 (400 ft2) in the set-up mode. 552.4 General Requirements. A park trailer as specified in 552.2 is intended for seasonal use. It is not intended as a permanent dwelling unit or fo1· commercial uses such as banks, clinics, offices, or similar. 552.5 Labels. Labels required by Article 552 shall be made of etched, metal-stamped, or embossed brass or stai nless steel; plastic laminates not less than 0.1 3 mm (0.005 in.) thic k; or anodized or alclad a luminwn not less than 0.5 mm (0.020 in.) thick or the equivalent. Informational Note: For guidance on other labe l criteria used in che park trailer industry, refer to ANSI Z535.4-201 l , Product Safel)' Signs and Labels.

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552.10

ARTICLE 552-PARK TRAILERS

Part II. Low-Voltage Systems 552.10 Low-Voltage Systems. (A) Low-Voltage Circuits. Low-voltage circuits famished and installed by the park trailer manufacturer, other than those 1-elated to braking, shall be subject to this Code. Circuits supplying lights subject to federal or state regulations shall comply with applicable government regulations and this Code. (B) Low-Voltage Wiring. (1) Material. Copper conductors shall be used for low-vo ltage circuits.

Exception: A metal chassis or frame shall be permitted as the return path to the source of supply. (2) Conductor

T}'pes. Conductors shall conform to the requirements for Type GXL, HDT, SGT, SGR, or Type SXL or shall have insulation in accordance with Table 310.4(A) or the equivalent. Conductor sizes 6 AWG through 18 AWG or SAE shall be listed. Single-\vire, low-voltage conductors shall be of the stranded type. Informational Note: See SAE JI 128-2015, Low Voltage Pri»W1)' Cable, for Types GXL, HDT, and SXL, and SAE J1127-2015, Low Voltage Bauery Cable, for Types SGT and SGR. (3) Marking. All insulated low-voltage conductors shall be surface marked at intervals not greater than 1.2 m (4 ft) as follows:

(l) (2)

(3)

Listed conductors shall be marked as required by the listing agency. SAE conductors shall be marked with the name or logo of the manufacturer, specification designation, and wire gauge. Other conductors shall be marked with the name or logo of the manufacnirer, temperanire rating, wire gauge, conductor material, and insulation thickness.

(C) Low-Voltage Wiring Methods. (1) Physical Protection. Conductors shall be protected against

physical damage and shall be secured. Where insulated conductors are clamped to the su-ucture, the conductor insulation shall be supplemented by an additional wrap or layer of equivalent material, except that j acketed cables shall not be required to be so protected. V\Tiring shall be routed away from sharp edges, moving parts, or heat sources.

mechanically secure. Ground connections shall be by means of coppe1- conductors and copper or coppe1--alloy terminals of the solderless type identified for the size of wire used. The surface on which ground terminals make contact shall be cleaned and be free from oxide or paint or shall be electrically connected through the use of a cadmium, tin, or zinc-plated internal/ external-toothed lockwasher or locking terminals. Ground terminal attaching screws, rivets or bolts, nuts, and lockwashers shall be cadmium, tin, or zinc-plated except rivets shall be permitted to be unanodized aluminum where attaching to aluminum su·ucnu-es. The chassis-grounding terminal of the battery shall be connected to the unit chassis with a minimum 8 AWG copper conductor. In the event the unbonded lead from the battery exceeds 8 AVvG, the bonding conductor size shal l be not less than that of the unbonded lead. (D) Battery Installations. Storage batte1-ies subject to this Code shall be securely attached to the unit and installed in a n area vaportight to the interior and ventilated directly to the exterior of the unit. 'Where batteries are installed in a compartment, the compartment shall be ventilated \vith openings having a minimum area of 1100 mm 2 (1.7 in. 2 ) at both tl1e top and at the botto m. Where compartment doors are equipped for ventilation, the openings shall be within 50 mm (2 in.) of the top and bottom. Batteries shall not be installed in a compartment containing spark- or flame-producing equ ipment. (E) Overcurrent Protection. (1) Rating. Low-voltage circuit wiring shall be protected by overcurrent protective devices rated not in excess of the ampacity of copper conductors, in accordance \vith Table 552.l O(E)(l) .

(2) T}'pe. Circuit breakers or fuses shall be of an approved type, including automotive types. Fuseholders shall be clearly marked with maximum fuse size and shall be protected against shorting and physical damage by a cover or equivalen t means. Informational Note: For furd1er information, see ANSI/SAE J 554-l 987, Standard for Electric Fuses (Cartridge Type); SAE Jl284-1988, Stand(l)ri for Bladi! Type Ekctric Fuses; and UL 275-2005, Standard for A !tlomotive Glass Tube Fuses.

(3) Appliances. Appliances such as pumps, compressors, heater blowers, and similar motor-driven appliances shall be installed in accordance with the manufacnirer's insu-uctions.

(2) Splices. Conductors shall be spl iced or joined with splicing devices that provide a secure connection or by brazing, welding, or soldering with a fusible metal or alloy. Soldered splices shall first be spliced or joined to be mechanically and e lecu-ically secure without so lde1~ and then soldered. All splices, joints, and free ends of conductors shall be covered \vith an insulation equivalent to that on the conducto1-s.

Motors that are controlled by automatic switching or by latch ing-type manual switches shall be protected in accordance with 430.32(B) .

(3) Separation. Battery and other low-voltage circuits shal l be

Table 552.lO(E)(l) Low-Voltage Overcurrent Protection

physically separated by at least a l~mm (Yz-in .) gap or oth er approved means from circuit5 of a different power source. Acceptable methods shall be by clamping, routing, or equivalent means that ensure permanent total separation. V\There circuits of different power sources cross, the external jacket of the nonmetallic-sheathed cables shall be deemed adequate separation .

Wire Size (AWG)

Ampacity

18 16 14 12 lO

6 8 15 20 30

Wire Type Str-2007, R.ecommended Praclice for lhe Design of Reliablii Industrial and Com1111!rcial Power Sys/Jims.

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701.12

(C) Storage Battery. Storage batteries shall be of suitable rating a nd capacity to supply and maintain the total load fo1· a min imum period of 1~ hours without the voltage applied to the load fa lling be low 87~ percen t of normal. Automotive-type batteries shall not be used. An a utomatic battery cha1·ging means shall be provided. (D) Generator Set. (1) Prime Mover-Driven. For a generator set driven by a prime m over approved by the authority having jur isdi ction and sized in accordance with 701.4, means sha ll be provided for au tomatically starting the prime mover upo n failure of th e no rmal service and for a utomatic u·ansfer and o peration of all required elecu·ical circu its. A ti me-delay featu re permi tting a 15-m inute setting shall be provided to avoid retransfer in case of shortt ime re-establishment of the normal sotn-ce . (2) Internal Combustion Engines as Prime Mover. ·w he re internal combustion engines a re used as the prim e m over, an on-site fue l su pply shall be provided with an on-p1·emises fue l supply sufficient for not less than 2 hours of full-demand operat ion of the system . Where power is needed for the operation of the fue l u·ansfe1· pumps to deliver fuel to a ge nerator set day tank, the pumps shall be con nected to the legally required standby power system. (3) Public Gas System, Municipal Water Supply. Prime movers sha ll not be sole ly dependent on a public utility gas system fo r their fuel su pply or on a municipal water supply for th e ir cooling systems. Means shall be provided for automa tically tran sferri ng one fuel su pply to anothe r where d ua l fuel supplies are used. Exception: \tVhere approved by the authority having jwisdiction, the use of other than on-site fuels shall be permitted where there is a ww probability of a simultanemts failure of both the offsite fuel delivery system and power from the outside electrical utility company.

(4) Battery Power. vVhe re a storage ba ttery is used fo r control or signal power or as the means of starting the prime mover, it shall be suitable for the purpose and shall b e equipped with an automatic charging mean s independent of th e generator set. (5) Outdoor Generator Sets. '1\7here a n o utdoor-housed generator set is equipped with a readily accessible d isconnecting means in accordance with 445.18, and the d isconnecting means is located within sight of th e b uild ing or su·ucture supplied, an additional disconnecting means sha ll not be requi red where u ngrounded conductors serve or pass thro ugh the build ing or structure. Wh ere the generator su pply cond ucto1·s terminate at a disconnecting mean s in or on a bu il ding or su·ucnu-e, the d iscon nectin g means sha ll meet the requirements of 225.36. (E) Uninterruptible Power Supplies . U ninterruptib le power su pplies used to provide power for legally required stand by systems shall comply with 701.12( B) and (C) . (F) Separate Service. V\7he1·e approved, a separate service shall be permitted as a legal ly required somce of stand by power. Th is service sha ll be in accordance with Article 230, with a sepac rate service drop o r lateral or a separate set of overhead o r underground service cond uctors sufficien tly rem ote eleco·ically and physically from any oth er se1vice to min imize the possibility of simultaneous interruption of supply from a n occu rrence in another service.

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701.12

ARTICLE 701- LEGALLY REQUIRED STANDBY SYSTEMS

(G) Connection Ahead of Service Disconnecting Means. v\There approved by the authority having jurisdiction, connections located ahead of and not within the same cabinet, enclosure, vertical switchgear section, or vertical switchboard section as the service disconnecting means shall be permitted. The legally required standby service shall be sufficiently separated from the normal main service disconnecting means to minimize simultaneous intermption of supply through an occurrence within the building or groups of buildings served. Informational Note: See 2'.{0.82 for equipment permiued on the supply side of a service disconnecting means.

(H) Fuel Cell System. Fuel cell systems used as a source of power for legally required standby systems shal l be of suitable rating and capacity to supply and maintain the total load for not less than 2 hours of full-demand operation. Installation of a fuel cell system shall meet the requirements of Parts II through VIII of Article 692. ·w here a single fuel cell system serves as the normal supply for the building or group of buildings concerned, it shall not serve as the sole source of power for the legally required standby syste m. (I) DC Microgrid Systems. Sources connected to a de microgrid system shall be permitted where the system is capable of being isolated from all nonlegally required sources. A de microgrid system used as a source of powe1- for legally required systems shall be of suitable rating and capacity to supply and maintain the total legally required load for not less than 2 hours of full-demand operation. \i\lhere a de microgrid system source se1ves as d1e normal supply for the building or group of buildings concerned, it shall not serve as the sole source of powe1- for the legally required standby system. (J) Unit Equipment. Individual unit equipment for legally required standby illumination shall consist of the following: (1) (2) (3)

(4)

A rechargeable battery A battery charging means Provisions for one or more lamps mounted on the equipment and shall be permitted to have terminals for remote lamps A relaying device arranged to energize the lamps automatically upon failure of the supply to the unit equipment

The batteries shall be of suitable rating and capacity to supply and maintain the total lamp load associated with the unit for not less than the following: (1)

(2)

For a period of 1 Y2 hours, without the voltage falling below 87\12 percent of normal voltage The unit equipment shall supply and maintain not less than 60 percent of the initial emergency illumination for a period of at least 1 Y2 hours.

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Unit equipment shall be permanently fixed in place (i .e ., not portable) and shall have all wiring to each unit in.stalled in accordance with the requirements of any of the wiring me thods in Chapter 3. Flexible cord-and-plug connection shall be permitted, provided that th e cord does not exceed 900 mm (3 ft) in length. The branch ci rcuit feedi ng the unit equipment shall be the same branch circuit as that serving the normal lighting in the area and corm ected ahead of any local switches. Legally required standby luminaires d1at obtain power from a unit equipment and are not part of the unit equipment shall be wired to the tmit equipment by one of the wiring methods of Chapter 3. Exception: ln a separate and uninterrupted area supplied by a minimum of three normal lighting circuits, a separate branch circuit for unit equipment shall be f>ermitted if it originates from the same panelboard as that of the normal lighting circuits and is provided with a lock-on feature.

Part IV. Overcurrent Protection 701.30 Accessibility. The branch-circuit overcurrent devices in legally required standby circuits shall be accessible to authorized persons only. 701.31 Ground-Fault Protection of Equipment. The alternate source for legally required standby systems shall not be required to provide ground-fault protection of equipment with automatic disconnecting means. Ground"fault indication at me legally required standby source shall be provided in accordance with 701.6(0) if ground-fault protection of equipment with automatic disconnecting means is not provided. 701.32 Selective Coordination. Legally required standby system(s) overcurrent devices shall be selectively coordinated wim all supply"'5ide overcurrent protective devices. Selective coordination shall be selected by a licensed professiona l engineer or othe1- qualified persons e ngaged p1-ima1-ily in me design, installation, or maintenance of e lectrical systems. The selection shall be documented a nd made available to those authorized to design, install, inspect, maintain, and operate the system. Exception: Sewctive coordination shall not be required between two ove1~ current devices located in smies if no load5 are connected in parallel with the downstream device. I nformational Note: See Informational Note Figure 701.32 for an example of how legally required standby system overcurrent protective devices (OCPDs) selectively coordinate with all supply-side OCPDs. OCPD D selectively coordinates wid1 OCPDs C, F, E, B, and A.

OCPD C selectively coordinates with OCPDs F, E, B, and A. OCPD F selectively coordinates with OCPD E. OCPD Bis not required to selectively coordinate wid1 OCPD A because OCPD B is not a legally required standby system OCPD.

NATIONAL ELECTRICAL CODE

2020 Edition

ARTICLE 702-0PTIONAL STANDBY SYSTEMS Normal Source

Emergency Source

I

702.5

indmtrial processes that, when stopped during any power outage, could cause discomfort, serious interruption of the process, damage to the product or process, or the like.

702.4 Capacity and Rating.

\ Q 0 Q)

(A) Available Fault Current. Optional standby system equipment shall be suitable for the available fault current at its terminals.

(000 l

(B) System Capacity.

• •

(2) Automatic Transfer Equipment. Where a utomatic transfer equipment is used, an optional standby system shall comply \vith 702.4(B)(2)(a) or (B)(2)(b ) in accordance with Article 220 or by another approved method. (a) Full Load. The standby source shall be capable of supplying the full load that is transferred by the automatic transfer equipment. (b) Load Management. Where a system is employed that will automatically manage the conn ected load, the standby source shal l have a capacity sufficient to supply the maximum load tl1at \viii be connected by the load manage ment system. 702.5 Transfer Equipment.

------- -· Informational Note Figure 701.32 System Selective Coordination.

(1) Manual Transfer Equipment. Where manual transfer equipment is used, an optional standby system shall have adequate capacity and rating for the supply of all equipment intended to be operated at one time. The user of the optional standb y system shall be permitted to select the load connected to the system.

Legally Required Standby

(A) General. Transfer equipment shall be required for all standb y systems subject to the requirements of this article and for which an electric utility supply is either the normal or standby source . Transfer switc hes shall not be pennitted to be reconditioned. Exception: Temporary connection of a portable generator without trans-

! er equipment shall be permitted where conditions of maintenance and

ARTICLE 702 Optional Standby Systems Part I. General 702.1 Scope. This article applies to the installation and operation of optional standb y systems. The systems covered by this article consist of those that ai·e permanently installed in their entirety, including prime movers, and those that are arranged for a connection to a premises wiring system from a portable alternate power supply. 702.2 Definition. T he definition in this section shal l apply \vi thin this article and throughout the Code.

Optional Standby Systems. Those systems intended to supply power to public or private facilities or property where life safety does not depend on the performance of the system. These systems are intended to supply on-site generated or stored power to selected loads either automatically or manually. Informational Note: Optional standby system s are typically installed to provide an a lternate source of electric power for such facilities as industrial and commercial buildings, farms, and residences and to serve loads such as heating and refrigeration systems, data processing and communications systems, and

2020 Edition

NATIONAL ELECTRICAL CODE

supervision ensure that only qualified persons service the installation and where the normal supply is physically isolated by a lockable disconnecting means or by disconnection of the normal supply conductors.

(B) Meter-Mounted Transfer Switches. Transfer S\vitches installed between the utility meter and the meter enclosure shall be listed meter-mounted transfer switches and shall be approved. Meter-moun ted o·ansfer S\vitches shall be of the manual type unless rated as determined by 702.4(B) (2) . Informational Note: For m ore information, see UL lOOSM, 1l"an.sfer Switch Equif1rnenl, Meter Mounted.

(C) Documentation. In other than dwelling units, the shortcircuit current rating of the transfer equipment, based on the specific overcurrent protective device type and settings protecting the o·ansfer equipment, shall be field marked on t11e exterior of the transfer equipment. (D) Inadvertent Interconnection. Transfer equipment shall be suitable for the intended use and shall be Listed, designed, and installed so as to prevent the inadvertent interconnection of all sources of supply in any operation of the u·ansfer equipment. (E) Parallel Installation. Transfer equipment and e lectric power production systems installed to permit operation in parallel with the normal source shall also meet the requirements of Article 705.

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702.6

ARTICLE 705 -INTERCONNECTED ELECTRIC POWER PRODUCTION SOURC...ES

702.6 Signals. Audible and visual signal devices shall be provided, where practicable, for the following purposes specified in 702.6(A) and (B) . (A) Malfunction. To indicate malfunction of the optional

standby source. (B) Carrying Load. To indicate that the optional standby source is carrying load.

Exception: Signals shall not be required for portabl,e standby power sources.

702.7 Signs. (A) Standby. A sign shall be placed at the service-entrance equipment for commercial and industrial installations that indicates the type and location of each on-site optional standby power source. For one- and two-family dwelling units, a sign shall be placed at the disconnecting means required in 230.85 that indicates the location of each permanently installed on-site optional standby power source disconnect 01- means to shut down the prime mover as required in 445.18(D) . (B) Grounding. vVhere removal of a grounding or bonding

connection in normal power sotu-ce equipment interrupts the grounding electrode conductor connection to the alternate power source(s) grounded conductor, a warning sign shall be installed at the normal power source equipment stating:

WARNING: SHOCK HAZARD EXISTS IF GROUNDING ELECTRODE CONDUCTOR OR BONDING JUMPER CONNECTION IN THIS EQUIPMENT IS REMOVED WHILE ALTERNATE SOURCE(S) IS ENERGIZED.

equipment grounding conductor shall be bonded to the syste m grounding electrode. 702.12 Outdoor Generator Sets. (A) Portable Generators Greater Than 15 kW and Permanently Installed Generators. V\There an outdoor housed generator set is equipped with a readily accessible d isconnecting means in accordance with 445.18, and the d isconnecting means is located within sight of the building or structure supplied, an additional d isconnecting means shall n ot be required where ungrounded conductors serve or pass through the building or structure. Whe1-e the generator supply conductors terminate at a disconnecting means in or on a building or structure, the disconnecting means shall meet the requirement~ of225.36.

(B) Portable Generators 15 kW or Less. vVhere a poi-table generator, rated 15 kW or less, is ins talled using a flanged inlet or other cord- and plug-type connection, a disconnecting means shall not be required where ungrounded conductors serve or pass through a building or structure.

(C) Power Inlets Rated at 100 Amperes or Greater, for Portable Generators. Equipment containing power inl ets for the connection of a generator source shall be listed for the intended use. Systems with power inlets shall be equipped with an interlocked disconnecting means. l.xception No. 1: 1f the inlet device is rated as a disconnecting means Exception No. 2: Supervised indtlstrial installations where perm.anent space is identified for the portabl.e generator located within line of sight of the power inlets shall not be required to have interlocked disconnecting means nor inlets rated as disconnects.

The warning sign(s) or labe l(s) shall comply with 110.21 (B) . (C) Powe r Inlet. ·where a power inlet is used for a temporary connection to a portable generator, a warning sign shall be placed near the inlet to indicate the type of de1-ived system that the system is capable of based on the wiring of the transfer equipment. The sign shall display one of the following warnings:

WARNING: FOR CONN ECTION OF A SEPARATELY DERIVED (BONDED NEUTRAL) SYSTEM ONLY or

WARNING: FOR CONNECTION OF A NONSEPARATELY DERIVED (FLOATING NEUTRAL) SYSTEM ONLY Part II. Wiring 702.10 Wiring Optional Standby Systems. The optional standby system wiring shall be permitted to occupy the same raceways, cables, boxes, and cabinets with other general wiring. 702.11 Portable Generator Grounding. (A) Separately Derived System. Where a portable optional standby source is used as a separately derived system, it shal l be grounded to a grounding electrode in accordance with 250.30. (B) N onseparately D erived System. Where a portable optional standby source is used as a nonseparately derived system, the

ARTICLE705 Interconnected Electric Power Production Sources Part I. General 705.1 Scope. This article covers installation of one or more electric power production sources operating i n paralle l with a primary source(s) of electricity. Informational Note: Examples of the types of primary sources include a utility supply or an on-site electric power source(s).

705.2 Definitions. The definitions in this section shall apply within this article and throughout the Code. Microgrid Interconnect Device (MID). A device that enables a microgrid system to separate from a nd reconnect to operate in parallel with a primary power source . Informational Note: Microgrid conu-olle rs typically are used to measure and evaluate e lectrical parameters and provide the logic for the signal to initiate and complete transition processes. IEEE Std 2030.7-2017, lliEE Standard for the Specification of Micro-grid ContmUers, and lEEE Std 2030.8-2018, IEEE Standard for the 1esting of Micmgrid Controllcrs, provide information on microgrid conu-ollers. lEEE Std 154 7-2018, /}EE Standard for Interconnection and lnlemf;embility of Distribuwd Energy Resources with Associaled E/,ect1ic Power Systems Interfaces, provides information on intercon-

nection requirements.

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2020 Edition

ARTICLE 705 - INTERCONNECTED ELECTRIC POV\7ER PRODUCTION SOURCES Microgrid System. A premises wiring system that has generation, energy storage, and load(s), or any combination thereof, that includes the ability to disconnect from and parallel with the primary source. Informational Note: The application of Article 705 to microgrid systems is limited by the exclusions in 90.2( B)(5) related to e lectric utilities. Additional info1·mation may be found in IEEE 1547, IEEE 2030.7, and IEEE 2030.8.

Power Source Output CircuiL The conductors between power production equipment and the service or distribution equipment. 705.6 Equipment Approval. All equipment shall be approved for the intended use . Interactive equipment intended to operate in parallel with e lectric power production sources including, but not limited to, interactive inverters, engine generators, energy storage equipment, and wind turbines shall be listed for in teractive function or be evaluated for interactive fun ctio n and have a field label applied, or both . 705.8 System Installation. Installation of one or more e lectrical power production sources operating in parallel with a primary source(s) of electrici ty shall be performed only by qualified persons. Informational Note: See Article 100 fo r the definition of Qualified Person.

705.10 Identification of Power Sources. A permanent plaque or directOl)' shall be instal led at e ach service equipment location, or at an approved readily visible location. The plaque or directOl)' shall denote the location of each power source disconnecting means for the building or structure and be g rouped with other plaques or directories for other on-site sources. The plaque or directory shall be marked with the w01-ding "CAUTION: MULTIPLE SOURCES O F P0\1\7ER. " Any posted diagrams shall be correctly oriented with respect to the diagram's location . The marking shall comply with 110.21 (B) .

J',xception: Installations with mu/,tiple c.porting power to the interconnected S)'Stem once all phases of the source to which it is connected are restm"iid.

(B) Three Phase. Three-phase power sources in interactive systems shall have all phases automatically de-energized upon loss of, or unbalanced, voltage in one or more phases unless the interconnected system is designed so that significant unbalanced voltages will not result.

Part II. Microgrid Systems 705.50 System Operation. Microgrid systems shal l be permitted to disconnect from the primary source of power or other interconnected e lectric powe1· production sow·ces and operate as an isolated microgrid system operating in island mode. 705.60 Primary Power Source Connection. Connections to primary power sotffces that are external to the microgrid system shall comply with the requiremen ts of705.l l, 705.12, or 705 .1 3. Power source conductors connecting to a m icrogrid system, including conductors supplying disu·ibution equipment, shall be considered as power source output conductors. 705.65 Reconnection to Primary Power Source. Microgrid systems that reconnect to p1·ima1·y power sources shall be provided with the necessary equipment to establish a synchronous u-ansition . 705.70 Microgrid Interconnect D evices (MID). Microg1·id interconnect devices shal l comply with the following: (1) (2) (3)

Be required for any connection between a m icrogrid system and a primary power source Be evaluated for the application and have a field labe l applied or be listed for the application Have sufficient number of overcurrent devices located to provide overcurrent protection from all sources Informational Noce: MLD functionality is often incorporated in an inceractive or multimode inverter, energy storage system, or similar device identified for interactive operation.

Informational Note No. l: Risks co personnel and equipmenc associated with the primary source could occur if an interactive e lectric power production source can operace as an incentional island. Special detection methods are required to determine that a primary source supply system oucage ha~ occurred and whether there should be automatic disconnection. When the

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2020 Edicion

ARTICLE 706- ENERGY STORAGE SYSTEMS

ARTICLE 706 Energy Storage Systems Part I. General 706.1 Scope. This article applies to all energy storage systems (ESS) having a capacity greater than 3.6 MJ (1 kWh) that may be stand-alone or interactive with other elecn-ic power production sources. These syste ms are primarily intended to store a nd provide energy during normal operating conditions.

Inverter Utilization Output Circuit. Conductors between the multimode or stand-alo ne inverte1- and utilization equipment. 706.3 Qualified Personnel. The installation and maintenance of ESS equipment and all associated wiring a nd interconnections shall be performed only by qualified persons. Informational Note: See Article 100 for tl1e definition of qualified fmson.

706.4 System Requirements. Each ESS shall b e provided with a nameplate plainly visible after installation and ma rked with the following: (1)

Informational Note No. 1: F'or batteries rated in ampere hours, kWh is equal to the nominal rated volrage times ampere-hour rating divided by 1000. Informational Note No. 2: There can be a subtle distinction betwee n a battery storing energy and an energy storage system. A battery sro ring energy is not necessarily an ESS. See Article 480. An ESS can be comprised of batteries storing energy. See Article 706. Informarional Note No. 3 : The following standards are frequently referenced for the installation of energy storage systems: (1) (2) (3)

(4) (5) (6) (7)

NF'PA 111-2016, Standard on Stored Elecllical Energy Emergency and Standby Systems NECA 416-2016, Ru.ommended Practice for Installing Energy Storage Systems (ESS) UL 8 10A, Electrochemical Capacitors UL 1973, Standard for Batteiies for Use in StatiorUtl)', Vehicle Auxiliary Powm; and Light Electric Rnil (LER) AjJj1lications UL I 989, Standant for StanrUJJ Balleries UL 9540, Standard for Safety Energy Storage !))stems and Equipment UL Subject 2436, Spill Containment For StationCtl)' Lead Acid Baltel)' Systems

706.2 Definitions. The definitions in this section shall apply only within this article.

(2) (3) (4) (5)

(6) (7) (8)

Informational Note No. I: ESS(s) can include but is not limited to batteries, capacitors, and kinetic e ne rgy devices (e.g., flywhee ls and com pressed air) . Energy storage systems can include inverters or converters to change volrage levels or to make a change between an ac or a d e system. Informational Note No. 2: These systems differ from other storage systems such as a UPS system, which is a power supply used to provide alternating current power to a load for some period of time in the e\•ent ofa power failure .

Flow Battery. An energy storage component similar to a fuel cell that stores its active materials in the form of two electrolytes external to the reactor interface. When in use, the e lectrolytes are transferred between reactor and storage tanks. Informational Note: Two commercially avai lable flow batte ry techno logies are zinc bromine and vanadium redox, sometimes referred to as pumped e lectrolyte ESS.

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NATIONAL ELECTRICAL CODE

Manufacturer's name, trademark, or other descriptive marking by whic h the o rganization 1-espo nsible for supplying the ESS can be identified Rated frequency Number of phases, if ac Rating (kW or kVA) Available fault current derived by the ESS a t the output terminals Maximum output and input current of the ESS at the output terminals Maximum output and input voltage of the ESS at the output terminals Utility-interactive capability, if applicable

706.5 Listing. Ene1-gy storage systems shall be listed. 706.6 Multiple Systems. Mul tiple ESSs shall be permitted to be installed in or on a single building or strucmre. 706.7 Maintenance. Energy storage system s shall be maintained in proper and safe operating condition . The required maintenance shall be in accordance with the manufacturer's requiremen ts and industry standards. A written record of the system maintenance shall be kept and shall include records of repairs and replacement5 necessary to maintain the system in proper and safe operating condition. Informational Note: F'or information related to general electrical equipment maintenance and developing an effective electrical preventive mainte nance (EPM) program, see NF'PA 70B-20 19, Recommended Practice for Electrical Equipment Maintenance, or ANSI/ NETA ATS-2017, Standard for Accej1lance Testing

Diversion Charge Controller. Equipment that regulates the ch arging process of an ESS by diverting powe1- from energy storage to direct-current or alternating-current loads or to an interconnected utility service. Energy Storage System (ESS). One or more components assembled together capable of storing e nergy and providing electrical energy into the premises wiring system or an elecffic power production and distribution netw'Ork.

706.15

Spu.ifiwtions for .Electrical Power Equijnnent and !))stems.

706.8 Storage Batteries. Storage batteries not associated with an ESS shall comply with Article 480. 706.9 Maximum Voltage. The maximum voltage of a n ESS shall be the rated ESS input and output voltage(s) indicated on the ESS nameplate(s) or system listing.

Part II. Disconnecting Means 706.15 Disconnecting Means. (A) ESS Disconnecting Means. A discon necting mea ns shall be provided for all ungrounded conductors derived from an ESS and shall be permitted to be integral to listed ESS equipment. The disconnecting means shall comply with all of the following: (1)

(2)

The disconnecting means sha ll be readily accessible. The disconnecting means shall be located within sight of the ESS. vVhere it is impractical to install the d isconnecting means within sig h t of the ESS, the disco1mect sha ll be installed as close as practicable, and the location of the disconnecting mea ns shall be field marked on or immedi-

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706.15

ARTICLE 706-ENERGY STORAGE SYSTEMS

ately adjacent to the ESS. The marking shall be of sufficient durability to withstand the environment involved and shall not be handwritten. The disconnecting means shall be lockable open in acco1·dance with 110.25.

(3)

For one-family and two-family dwellings, a disconnecting means or its remote control shall be located at a readily accessible location outside the building. (B) Remote Actuation. Where controls to activate the disconnecting means of an ESS are u sed and are not located within sight of the system, the location of the controls shall be field marked on the disconnecting means. (C) Notification and Marking. Each ESS disconnecting means shall plainly indicate whether it is in the open (off) or closed (on) position and be permanently marked "ENERGY STORAGE SYSTEM DISCONNECT." The disconnecting means shall be legibly marked in the field to indicate the following:

Nominal ESS ac voltage and maximum ESS de voltage Available fault current derived from the ESS An arc-flash label applied in accordance with acceptable industry practice Date the calculation was performed

(1) (2) (3) (4)

Exception: List items (2), (3), and (4) shall not apply to one- and twoJamily dwellings. Informational Nole No. 1: lnduslry practices for equipmem labe ling are described in NFPA 70£2018, Standard for Ekcl1ical Safely in lhe Workfilace. This srandard provides specific criteria for developing arc-flash labe ls for equipmem that provides nominal system volrage, incidem energy levels, arc-flash boundaries, minimum required levels of personal protective equipment, and so forth. Informational Note No. 2: Battery equipmem suppliers can provide information about available fault current on any particular battery model.

For ESS disconnecting means whe1·e the line and load terminals may be energized in the open position, the device shall be marked with the following words or equivalent: WARNING ELECTRIC SHOCK HAZARD TERMINALS ON THE LINE AND LOAD SIDES MAY BE ENERGIZED IN THE OPEN POSITION The notification(s) and marking(s) shall comply with 110.2l(B) .

(B) Identified Interactive Equipment. ESS that operate in parallel with other ac sources shall use inveners that are Listed and identified as interactive. (C) Loss of Interactive System Power. Upon loss of a primary source of powe1·, an ESS with a utility-interactive inverter shall comply with the requirements of705.40 . (D) Unbalanced Interconnections. Unbalanced ac connections between an ESS and other ac electric power production sources shall be in accordance with 705.45 (E) Other Energy Sources. The connection of an ESS to other energy sources shall be in accordance with 705.12 and Parts III and VI of Article 712.

(F) Stand-Alone Operation. Where the output of an ESS is capable of operating in stand-alone mode, the requirements of 710.1 5 shall apply.

Part III. Installation Requirements 706.20 General. (A) Ventilation. Provisions appropriate to th e energy storage technology shall be made for sufficient diffusion and ventilation of any possible gases from the storage device, if present, to p1·event the accumulation of an explosive mixture. Ventilation of an ESS shall be permitted to be provided in accordance with the manufacturer's recommendations and listing for the system. Informational Note No. l: See NFPA 1-2018, Fire Code, Chapter 52, for ventilation considerations for specific battery chemistries. Informational Note No. 2: Some storage technologies do nol require ventilation. Informational Note No. 3: A source for design of ventilation of battery systems is IEEE 1635-2018/ ASHRAE Guideline 21-2018, Guide for lhe Venlilalion and Thermal Management of Baue1ies for Slalionm)• Apfilicalions. Informational Note No. 4: Fire protection considerations are addressed in NFPA 1-2018, Fire Code.

(B) Dwelling Units. An ESS for one- and two-family dwelling units shall not exceed 100 volts de between conductors or to ground.

Exception: liWiere live parts are not accessible during routine ESS maintenance, a maximum ESS voltage of 600 volts de shall be permitted.

(C) Spaces About ESS Components.

(D) Partitions Between Components. Where circuits from the input or output terminals of energy storage components in an ESS pass through a wall, floor, or ceiling, a readily accessible disconnecting means shall b e provided within sight of the energy storage component. Fused disconnecting means or circuit breakers shall be permitted to be used.

(1) General. \l\Torking spaces for ESS shall comply with 110.26 and 110.34.

706.16 Connection to Energy Sources. The connection of an ESS to sources of energy shall comply with 706.1 6(A) through

Informational Note: Additional space may be needed to accommodate ESS hoisting equipment, tray removal, or spill containment.

(F).

(A) Source Disconnect. A disconnect that ha5 multiple sources of power shall disconnect all energy sources when in the off position .

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(2) Space Between Components. ESSs shall be permitted to have space between components in accordance wi th the manufacturer's instructions and listing.

706.21 Directory (Identification of Power Sources). ESS shall be indicated by markings or labels that shall be in accordance with 110.2l(B) .

NATIONAL ELECTRICAL CODE

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ARTICLE 706- ENERGY STORAGE SYSTEMS

706.33

(A) Facilities with Utility Services and ESS. Plaques or directo1-ies shall be installed in acco1-dance with 705.10 and 712.1 0.

rating of the overcurrent devices shall be permitted to be not less than the maximum currents calculated in 706.30(B).

(B) Facilities with Stand-Alone Systems. Plaques or d irectories shall be installed in accordance with 710.10.

(C) Direct Current Rating. Overcurrent protective devices, either fuses or circuit breakers, used in a n y de portion of an ESS shall be listed for de and shall have the appropriate voltage, current, and interrupting ratings for the application.

Part IV. Circuit Requirements 706.30 Circuit Sizing and Current. (A) Maximum Rated Current for a Specific Circuit. Th e maximum current for the specific circuit shall be calculated in accordance with 706.30(A)(l) through (A)(5) . (I ) Nameplate-Rated Circuit Current. Circuit current shall be the rated current indicated on the ESS nameplate (s) or system listing. \ 1\lhere the ESS has separate input (charge) and output (discharge) circuits or ratings, these shall be considered individually. Where the same terminals on the ESS are used for charging and discharging, the rated current sha ll be the greater of the two. (2) Inverter Output Circuit Current. The maximum current shall be the inverter contin uous output current rating. (3) Inverter Input Circuit Current. The maximum current shall be the continuous inverter input current rating when the inverter is producing rated power at the lowest input voltage.

(D) Current Limiting. A listed and labeled current-limiting overcurrent protective device s hall be installed adjacent to the ESS for each de output c ircuit. Exception: Where cu1Tent-limiting overcurrent protection is provided for the de output circuits of a listed ESS, additional current-limiting overcurrent devices shall not be required. (E) Fuses . Means shall be provided to d isconnect a ny fuses associated with ESS equipment and components when the fuse is energized from both d irections and is accessible to other than qualified persons. Switches, pullouts, or similar devices that are rated for the application shall be permitted to serve as a means to disconnect fuses from alJ sources of supply.

(F) Location. \.\There circuits from the input or output terminal5 of energy storage compone nts in an ESS pass d1rough a wall, floor, or ceiling, overcurrent protection shall be provided at the energy storage component end o f the circuit. 706.33 Charge Control.

(4) Inverter Utilization Output Circuit Current. The maximum current shall be the continuous ac output current rating of the inverter when the inverter is producing rated power.

(A) General. Provisions sha ll be provided to con trol the charging process of the ESS. All adjustable means for control of the charging process s hall be accessible only to qualified pe1-sons.

(5) DC to DC Converter Output Current. T he maximum cu rrent shall be the de-to-de converter continuous output current rating.

(B) Diversion Charge Controller.

(B) Conductor Ampacity. The ampacity of the feeder circuit conductors from the ESS(s) to the wiring system serving the loads to be se1-viced b y the system shall not be less than the greater of the (1) nameplate(s)-rated circuit current as determined in accordance with 706.30(A) ( 1) or (A) (2) the rating of the ESS(s) overcurrent protective device(s). (C) Ampacity of Grounded or Neutral Conductor. ff the

output of a single-phase, 2-wire ESS output(s) is connected to the grounded 01- neuo-al conductor and a single ungrounded conductor of a 3-wire system or of a 3-phase, 4-wire, wyeconnected system, the maximum unbalanced neutral load current plus the ESS(s) output rating shall not exceed the ampacity of the grounded or neutral conductor. 706.31 Overcurrent Protection. (A) Circuits and Equipment. ESS circuit conductors shall be protected in accordance wid1 the requirements of Article 240. Protection devices for ESS c ircui ts shall be in accordance with the requirements of 706.31 (B) through (F) . Circuits shall be protected at the source from overcurrent. (B) Overcurrent Device Ampere Ratings. Overcurrent protective devices, where required, shall be rated in accordance with Article 240 and the rating provided on systems serving the ESS and shall be not less d1an 125 percent of the maximum currents calculated in 706.30(A) . Exception: Where the assembly, including the overcurrent protective devices, is listed for operation at 100 percent of its rating, the ampere

2020 Edition

NATIONAL ELECTRICAL CODE

(I) Sole Means of Regulating Charging. An ESS empl oying a dive1-sion charge controller as the sole means of regulating charging shall be equipped with a second independent means to prevent overcharging of the storage device. (2) Circuits with Diversion Charge Controller and Diversion Load. Circuits contain ing a d iversion charge controller a nd a diversion load shall comply with the fo llowing: (l)

(2)

The current rating of the diversion load shall be less than or equal to the cu rrent rating of the diversion load charge conu-oller. The vol tage rating of the d iversion load sha ll be g reater than the maximum ESS voltage. The power rating of the d iversion load shall be at least 150 percent of the power rating of the charging source. The conductor arnpacity a nd the rating of the overcurrent device for this ci rcuit sha ll be at least 150 percent of the maximum current rating of the diversion charge controller.

(3) ESS Using Interactive Inverters. Systems using interactive inverters to conn·ol energy storage state-of-charge by diverting excess power into an a lternate elecn-ic power production and d istribution system, such as ut ility, shall comply with 706.33(B) (3) (a) and (B)(3) (b) . (a) These systems shall n ot be required to comply with 706.33(B)(2) . (b) These systems shall have a second, independent means of conn-oiling the ESS charging process for use when the alternate system is not available or when th e primary charge controller fa ils or is disabled. (C) Charge Controllers and DCto-DC Converters. Wh ere charge controllers a nd other DC-to-DC power con verters that

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706.40

ARTICLE 708-CRITICAL OPERATIONS POWER SYSTEMS (COPS)

in crease or decrease the o utput current or o utput voltage with 1-espect to the input current or input voltage are installed, all of the following shall apply: ( 1)

(2)

The ampacity of the conductors in output circuits shall be based on the maximum rated continuous output current of the charge controller or converter for the selected output voltage range. The voltage rating of the output circuits shall be based on the maximum voltage output of the charge controller or converter for the selected output voltage rnnge.

Part V. Flow Battery Energy Storage Systems Part V applies to ESSs composed of or containing flow batteries. Informational Note: Due to the unique design features and difference in operating characteristics of flow batteries as com pared with that of storage batteries such as lead acid or lithium ion batteries, the requirements for flow batteries have been included here rather than in Article 480.

706.40 General. All electrical connections to and from the system and system components shall be in accordance with the applicable provisions of Article 692. The system and system components shall also meet Parts I, JI, and III of this article . Unless othe1wise d irected by this article, flow battery ESS shall comply with the applicable provisions of Article 692.

ARTICLE708 Critical Operations Power Systems (COPS)

Part I. General

708.1 Scope. This article applies to the installation, operation, monitoring, control, and maintenance of the portions of the premises wiring system intended to supply, d isu-ibute, and conu-ol electricity to designated critical operations areas (DCOA) in the event of d isruption to elements of the normal system. Criti cal operations power syste ms are those systems so cla5sed by municipal, state, federal, or othe1- codes by any governmental agency having jurisdiction or by faci.lity e ng ineering documentation establishing the necessity for such a system. T hese systems include but a1-e not limited to power systems, HVAC, fire alarm, security, communications, and signali ng for designated critical operations areas. Informational Note No. l: Critical operations power systems are generally installed in vital infrastructure facilities that, if destroyed or incapacitated, would disrupt national security, the economy, public health or safety; and whe re enhanced e lectrical infrastructure for continuity of operation has been deemed necessary by governmental auth ority.

706.41 Electrolyte Classification. The electrolyte(s) that are acceptable for use in the batteries associated with the ESS shall be identified by name and chemical composition. Such identification shall be provided by readily discernable signage adjacent to every location in the system where the electrolyte can be put into or taken out of the system .

Informational Note No. 2: For ti.trthe r information on disaster and emergency management, see NFPA 1600-2019, Slandard on

706.42 Electrolyte Contairunent. Flow battel)' systems shall be provided with a means for electrolyte containment to prevent spills of e lectrolyte from the system . An a larm system shal l be provided to signal an electrolyte leak from the system . Electrical wiring and connections shall be located and routed in a manne1· that mitigates the potential for exposure to electrolytes.

Informational Note No. 4: For specification of locations where emergency lighting is considered essential to life safety, see NFPA 101-2018, Life Safety Code, or the applicable building code.

706.43 Flow Controls. Controls shall be provided to safely shut down the system in the event of electrolyte blockage. 706.44 Pumps and Other Fluid Handling Equipment. Pumps and other fluid handling equipment are to be rated/specified suitable fo1· exposure to the e lectrolytes .

Part VI. Other Energy Storage Technologies Part VI applies to ESSs using other technologies intended to store energy and when there is a demand for electrical power to use the stored energy to generate the needed power.

706.50 General. All elecu-ical connections to and from the system and system components shall be in accordance with the applicable provisions of this Code. Unless otherwise di1-ected b y this article, other energy storage technologies shall comply with the applicable provisions of Part III of Article 705.

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Conlinuily, Emergency, and Crisis ManagemenL Informational Note No. 3: For ford1er information regarding performance of emergency and standby power systems, see N FPA Ll 0-2019, Slandard for Emergency and Standby Power Systems.

I nformational Note No. 5: For forther information regarding physical security, see NFPA 730-2018, Guide/or Premises Secmil)'· Informational Note No. 6: Threats to facilities that may require transfer of operation LO d1e critical systems include both nalllrally occurring hazards and human-caused events. See also A.5.3.2 of NFPA 1600-2019, Slandard on Conlinuil)', Emergency, and

Crisis Managemenl. Informational Note No. 7: See Informative Annex F, Avai lability and Re liability for Critical Operations Power Systems; and Development and Implementation of Functional Performance Tests (FPTs) for Critical Operations Power Systems. Informational Note No. 8: See Informative Annex G, Supervisory Control and Data Acquisition (SCADA). Informational Note No. 9: Text that is followed by a reference in brackets has been extracted from NFPA 1600-2019, Slandard on Conlinuily, Ernergency, and Crisis ManagemenL Only editorial changes were made to the extracted text to make it consistent wid1 this Code.

NATIONAL ELECTRICAL CODE

2020 Edition

ARTICLE 708- CRITICAL OPERATIONS POWER SYSTEMS (COPS) 708.2 Definitions. The definitions in this section shall apply within this article and throughout the Code. Commissioning. The acceptance testing, integrated system testing, operational nme-up, and start-up testing is the process b y wh ich baseline test results verify the proper operation and sequence of operation of elecu·ical equipment, in addition to developing baseline criteria by which funire trend analysis can identify equipment deterioration. Critical Operations Power Systems (COPS). Power systems for facilities or parts of facilities that require continuous operation for the reasons of public safety, emergency management, national security, or business continuity. Designated Critical Operations Areas (DCOA). Areas within a facility or site designated as requiring critical operations power. Supervisory Control and Data Acquisition (SCADA). An electronic system that provides mon itoring and controls for the operation of the critical operations power system. This can include the fire alarm system, security system, conu·ol of the HVAC, the start/stop/mon itoring of the power supplies and elecu·ical distribution system, annunciation and communications equipment to emergency personnel, facility occupants, and rem ote operators. 708.4 Risk Assessment. Risk assessment for critical operations power systems shall be documented and shall be conducted in accordance with 708.4(A) through (C) . Informational Note: Chapter 5 of NFPA 1600.2019, Standard on Continuity, Emergency, and Crisis Ma11agement, provides additional guidance concerning risk assessmenr and hazard analysis.

(A) Conducting Risk Assessment. In critical operations power systems, risk assessment shall be performed to identify hazards, the likelihood of their occurrence, and the vulnerability of the electrical system to those hazards. (B) Iden tification of Hazards. Hazards to be considered at a minimum shall include, but shal l not be limited to, the following: (1) (2)

Namrally occurring hazards (geological, meteorological, and biological) Human-caused events (accidental and intentional) (1600:5.3.2]

(C) Developing Mitigation Strategy. Based on the results of the 1·isk assessment, a strategy shall be developed and implemented to mitigate the hazards that have not been sufficiently mitigated by the prescriptive requiremen ts of this Code.

708.5 Physical Security. Physical security shall be provided for critical operations power systems in accordance with 708.5(A) and (B) . (A) Risk Assessment. Based on the results of the risk assessment, a strategy for providing physical security for critical operations power systems shall be developed, documented, and implemented. (B) Restricted Access. Electrical circuits and equipment for critical operations power systems shall be accessible to qualified personnel only.

2020 Edition

NATIONAL ELECTRICAL CODE

708.10

708.6 Testing and Maintenance. (A) Conduct or Witness Test. Th e authority having jurisdiction shall conduct or wimess a test of the complete syste m upon installation and periodically afterward. (B) Tested Periodically. Systems shall be tested periodically on a schedule approved by th e authority having jurisdiction to ensure the systems are maintained in proper operating condition.

(C) Maintenance. The authority having jurisdiction shal l require a documented preventive maintenance program for c1·itical operations power systems. Informational Note: For information concerning maintenance, see NFPA 70B-2019, Recommended Practice for Electrical Equipment

Maintenance. (D) Written Record. A written record shall be kept of such test5 and maintenance. (E) Testing Under Load. Means for testing a ll critical power systems during maximum anticipated load conditions sha ll be provided. Informational Note: For information concerning testing and maintenance of emergency power supply systems (EPSSs) that are a lso applicable to COPS, see NFPA 110-2019, Standard for

.Emergen.c:i• and Standby Power S)'stems.

708.8 Commissioning. (A) Commissioning Plan. A commissioning plan shall be developed and documented. Informational Note: For funher information on developing a commissioning progran1 see NFPA 70B-2019, Recommended Prac-

tice for Electrical Equipment Maintenance. (B) Component and System Tests. The installation o f the equipment shall undergo component a nd syste m tests to ensure that, when energized, the system will function properly. (C) Baseline Test Results. A set of baseline test 1·esults shall be documented for comparison with fumre periodic maintenance testing to identify equipment deteri oration .

(D ) Functional Performance Tests. A functional performance test program shall be established, documented, and executed upon complete installation of the critical system in order to establish a baseline 1·eference for funire performance requirements. Informational Note: See Informative Annex F for more information on developing and implementing a functional performance test program.

Part II. Circuit Wiring and Equipment 708.10 Feeder and Branch Circuit Wrring. (A) Identification. (1) Boxes and Enclosures. In a building or at a structure where a critical operations power system and any other type of power system are present, a ll boxes and enclosures (including transfe1· switches, generators, a nd power panels) for critical operations power system c ircuits shall be permanen tly ma rked so they will be readily identified as a component of the critical operations power system.

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708.10

ARTICLE 708-CRITICAL OPERATIONS POWER SYST EMS (COPS) Informational Note No. 2: The listing organization provides information for fire-resistive cable systems on proper installation requirement~ to maintain the fire rating.

(2) Receptacle Ide ntification. In a building in which COPS are present with other types of powe1- systems described in other sections in this article, the cover plates for the receptacles or the receptacles themselves supplied from the COPS shall have a distinctive color or marking so as to be readily identifiable . Nonlocking-type, 125-volt, 15- and 20-ampere receptacles supplied from the COPS s hall have an illuminated face or an indicator light to indicate that there is power to the receptacle.

(3)

.Exception: If the COPS supplies power to a DCOA that is a stand-alone building, receptacle cover plates or the receptacles themselves shall not be required to have distinctive marking.

(3) Floodplain Protection. Where CO PS feeders are installed below the level of the 100-year floodpla in, the insulated c ircuit conductors shall b e listed for use in a wet location and be installed in a wiring method that is permitted for use in wet locations.

(B) Wiring. Wiring of two or more COPS circuits supplied from the same source shall be permitted in the same raceway, cable, box, or cabinet. Wi1-ing from a COPS source or COPS source distribution overcurrent protection to critical loads shall be kept entirely independent of all other wiring and equipment.

(4)

(D ) COPS Branch Circuit Wiring.

(l)

Outside the DCOA. COPS branch circuits installed outside

(2)

the DCOA shall comply with the physical and fire protection requirements of 708. lO(C) (l) through (C) (3) . Within the DCOA. Any of the wiri ng meth ods recognized in Chapter 3 of this C:Ode sha ll be pe1·mitted within the DCOA.

Exception: Where the COPS feeder is installed in transfer equipment enclosures. (C) COPS Feeder Wiring Requirements. COPS feeders shall comply with 708.lO(C)(l) through (C)(3) . (1) Protection Against Physical Damage. The wiring of the COPS system shall be protected against physical damage. Only the following wiring methods shall be permitted: (1)

(2)

(3)

Rigid metal conduit, intermediate metal conduit, or Type MI cable. Where encased in not less than 50 mm (2 in.) of concrete, any of the following wiring methods shall be permitted: a. Schedule 40 or Schedule 80 rigid polyvinyl chloride condu it (Type PVC) b. Reinforced thermosetting resin conduit (Type RTRC) c. Elecu·ical metallic tubing (Type EMT) d . Flexible nonmetalli c or jacketed metallic raceways e. Jacketed metallic cable assemblies listed for installation in concrete Where provisions must be made for flexibility at equipment connection, one or more of the following shall also be permitted: a . Flexible metal fittings b . Flexible metal conduit with listed fittings c. Liquidtight flexible metal conduit with listed fittings

708.11 Branch Circuit and Feeder Distribution Equipment. (A) Branch Circuit Distribution Equipment. COPS branch circuit distribution equipment shall be located within the same DCOA as the branch circu its it supplies. (B) Feeder Distribution Equipment. Equipment for COPS feeder circuits (including transfer equipment, transformers, and panelboards) shall comply with (l) and (2): (1)

(2)

The cable or raceway is protected by a listed electrical circuit protective system with a minimum 2-hour fire rating. Informational Note: The listing organization provides information for e lectrical circuit protection systems on proper installation requirements to maintain the fire rating.

(2)

The cable or raceway is a listed fire-resistive cable system with a minimum 2-hour fire rating. lnformational Note No. l: Fire-resistive cables are tested to ANSI/ UL 2196-2017, Standard for Fire Test for Circuit Integrity of Fire-Resistive Power, Instrumentation, Control and Data Cabws.

708.14 Wiring of HVAC, Fire Alarm, Security, Emergency Communications, and Signaling Systems. AU conductors or cables shal l be installed using any of the metal wiring methods permitted by 708. lO(C)(l) and, in addition, shall comply with the following, as applicable: (1)

(2)

(3)

(4)

(5) (6)

(7)

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Be located in spaces with a 2-hour fire resistan ce rating Be located above the 100-year floodplain

708.12 Feeders and Branch Circuits Supplied by COPS. Feeders and branch circuits supplied by the COPS shall supply only equipment specified as required for critical operations use.

(2) Fire Protection for Feeders. Feeders shall meet one of the following conditions:

(l)

The cable or raceway is protected by a listed fire-rated assembly that has a minimum fire rating of 2 hours. The cable or raceway is encased in a minimum of 50 mm (2 in .) of concrete.

All cables for fire a larm, security, s ignaling systems, and emergency communications shall be shielded nvisted pair cables or installed to comply with the performance 1-equirements of the system. Shields of cables for fire alarm, security, signalin g systems, and emergency communications shall be arranged in accordance with the manufacturer's published installation insu·uctions. Optical fiber cables s hall be used for connections between two or more buildings on the prope1·ty and under single management. A listed primary protector shall be provided on all communications circuits. Listed secondary protectors shall be provided at the terminals of the commw1ications circuits. Conductors fo1- all conu-ol circuits rated above 50 volts shall be rated not less than 600 volt5. Communications, fire a larm, and signaling circuits shall use relays with contact ratings that exceed c ircuit voltage and current ratings in the con trolled circuit. All cables for fire alarm, security, and signaling systems shall be riser-rated and sha ll be a listed 2-hour e lectrical

NATIONAL ELECTRICAL CODE

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ARTICLE 708- CRITICAL OPERATIONS POWER SYSTEMS (COPS)

(8)

circuit protective syste m. Emergency communicatiorL~ cables shall be Type CMR-CI or shall be riser-rated and shall be a listed 2-hour electrical circuit protective system . Control, monitoring, and power wiring to HVAC systems shall be a listed 2-hour electrical circuit protective system.

Part ill. Power Sources and Connection 708.20 Sources of Power. (A) General Requirements. Current supply shall be such that, in the event of failure of the normal supp ly to the DCOA, critical operations power shall be available within the time required for the application . The supply system for critical operations power, in addition to the normal services to the building and meeting the general requirements of this section, shal l be one or more of the types of systems described in 708.20(E) through (H) . Informational Note No. I: Assignment of degree of reliability of the recognized critical operations power system depend~ on the carefol evaluation in accordance with the risk assessment. Informational Note No. 2: For guidance about determining degree of reliability, see IEEE 3006.5-2014 Recommended Practice for the Use of Pmbability Methods for Conducting a Reliability A nal)'Sis of Industrial and Commercial Power S)•stems.

(B) Fire Protection. Where located within a building, equipment fo1· sources of power as described in 708.20(E) through (H) shall be installed either in spaces fully protected by an approved automatic fire protection system or in spaces with a 2hour fire rating. (C) Grounding. All sources of power shall be grounded as a separately derived source in accordance with 250.30.

Exception: Hihere the equipment containing the main bonding jumper Qr system bonding jumper for the normal source and the feeder wiring to the transfer eqtiipment are installed in accordance with 708.1 O(C) and

708.22

(4) Battery Power and Dampers. v\ihere a storage battery is u sed for conu·ol or signal power or as the means of starting the prime mover, it shall be suitable for the purpose and shall be equipped with an automati c charging means independent of the generator set. Where the battery charger is required for the operation of the generator set, it shall be con nected to the COPS. \.\There power is required for the operation of dampers used to ventilate the generator set, the dampers shall be connected to the COPS. (5) Outdoor Generator Sets. (a) Pennanently Installed Generators and Portabl.e Generators Greater 17wn 15 kW \!\There an outdoor housed generator set is equipped with a readily accessible disconnecting means in accordance with 445.18, and the d isconnecting means is located within sight of the building or structure suppl.ied, a n additional disconnecting means shall not be required where ungrounded conductors serve or pass through t he building o r structure. V\There the generator supply conductors terminate at a disconnecting means in or on a building or structure, the disconnecting means shall meet the 1·equirements of 225 .36. (b) P, Telecornmimications Pathways and S/)(tces; ANSl/TlA-570-C-2012, Residential 7ewcornrnunications Infrastructure Standard; ANSI/ TlA-1005-A-2012, 7elecorn11wnications l nfmstnictttre Standard for Indmtrial Premises; ANSI/ TlA-1 179-2010, Heallhcare Facility Telecommunications lnfrastrttctttre Standard; ANSl/TlA-4966-2014, Telecomrnunications Infrastructure Standard for Educational Facilities; and other ANSI-approved installation standards. Informational Note No. 2: See NFPA 90A-2018, Standardfor lhe Installation of Air-Conditioning and Ventilating S)•stems, for discrete

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NATIONAL ELECTRICAL CODE

2020 Edition

ARTICLE 800- GENERAL REQUIREMENTS FOR COMMUNICATIONS SYSTEMS combustible 300.22(C) .

components

installed

in

accordance

800.53

with

tors are insulated and that a clearance of not less than 1.0 m (40 in. ) is maintained between t he tw·o services at t he pole.

Informational Note No. 3: Paint, p laster, cleaners, abrasives, corrosive residues, or other contaminants may result in an undetermined alteration of wire and cable properties.

(B) Above Roofs. Communicati ons \vires a nd cables and CATV type coaxial cables shall have a vertical clearance of not less than 2.5 m (8 ft) fro m a ll poin ts of roofs above which they pass.

800.25 Abandoned Cables. The accessible portion of abandoned cables shall be removed. Where cables are identified for fun1re use with a tag, the tag shall be of sufficien t durability to withstand the environment involved. 800.26 Spread of Ftre or Products of Combustion. Installations of cables, commu n ications raceways, cable routing assemblies in hollow spaces, vertical shafts, a nd ventilation or airhandling ducts shall be made so that the possible spread of fire or products of combustion will not be substantially increased. Openings around penetrations of cables, communications raceways, and cable routing assemblies through fire-re sistant-rated walls, partitions, floors, or ceilings shal l be firestopped using approved methods to maintain the fire resistance rating. Informational Note: Directories of electrical construction materials published by qualified testing laboratories contain many listing instal lation restrictions necessary to maintain the fireresistive rating of assemblies where penetrations or open ings are made. Building codes also contain restrictions on membrane penetrations on opposite sides of a fire resistance- rated wal l assembly. An example is the 600 mm (24 in.) minimum horizontal separation that usually applies between boxes installed on opposite sides of the wall. Assistance in complying with 800.26 can be found in building codes, fire resistance directories, and product listings.

800.27 Temperature Limitation of Wires and Cables. No wire or cable sha ll be used in such a manner that its operating temperanire exceeds that of its rating.

Part II. Wires and Cables Outside and Entering Buildings 800.44 O vemead (Aerial) Wires and Cables. Overhead (aerial) wires and cables entering buildings shall comply with 800.44(A) through (D) . Informational Note: For additional information regarding overhead (aerial) wires and cables, see ANSI C2-2017, National Elecl1ical Safety Code, Parl 2 Sa/el)• Ruws /01· Overhead Lines.

(A) On Poles and In-Span. Where wires a nd cables a nd electric light or power conductors are supported by the same pole or are run parallel to each other in-span, the conditions described in 800.44(A)( l ) through (A)(4) shall b e met. (1) Relative Location. Where practicable, the wires and cables shal l be located be low the e lectric light or power conductors. (2) Attachment to Cross-Arms. Wires and cables shall no t be attach ed to a cross-arm that carries electric light o r power conductors. (3) Climbing Space. The climbing space through wires and cables shall comply with the requirements of225.14(D) .

Exception No. 1: Communications wires and cables and CATV type coaxial cables shall not be required to have a vertical clearance of not l.ess than 2.5 m (8 ft) above auxiliary buildings, such as garages and the like. Exception No. 2: A reduction in clearance above only the overhanging portion ofthe roof to not less than 450 mm ( 18 in.) shall be permitted if ( 1) not m01ri than 1. 2 m ( 4 ft) of communications service-drop cond uctm-.5 pass above the roof overhang and (2) they a?ri terminated at a through- or above-the•roof raceway or approved support. Exception No. 3: Wheff the roof has a slope ofnot less than 100 mm in 300 mm (4 in. in 12 in.), a reduction in clearance to not less than 900 mm (3 ft) shall be permitted. I nformational Note: For additional information regarding overhead (aerial) wires and cables, see ANSI/ LEEE C2-2017, Naiional Electrical Safely Code, Parl 2, Safely Rules for Overhead Lines.

(C) On Masts. Overhead (aerial) communications and CATV type coaxial cables shall be permitted to be attached to an above-the-roof raceway mast that does not e nclose or support conductors of electric lig h t or power circuits. (D) Between Buildings. Communi cations a nd CATV type coaxia l cables extending betwee n bui ldings or su·uctures, and also the support5 01- attachment fixnires, shall be identified a nd shall have sufficient strength to \vithsta nd the loads to wh ich they might be subjected.

Exception: °!'\!here a coaxial cable does not have sufficient strength to be selfsupporting, it shall be attached to a supp1Jrting messenger cable that, together with the attachment fixtures or supports, shall be acceptable f1Jr the purpose and shall have sufficient strength to withstand the l.oad5 to which they may be subjected.

800.49 Metal Entrance Conduit Grounding. Metal conduit containing entrance \'lire or cable shall be con nected by a bonding conductor or grounding electrode conductor to a grounding electrode or, where present, the building grounding electrode system in accordance with 800.lOO(B) . 800.53 Separation from Lightning Conductors. Where practicable, a separation of at least 1.8 m (6 ft) sha ll be maintained between lightning conductors a nd all communication wires and cables and CATV type coaxia l cables on buildings. Informational Note No. l: For additional information regarding overhead (aerial) wires and cables, see ANSI C2-20 17 National Electrical Sa/el)' Code, Parl 2, Safel)' Rules/or Ormfwad Lines. I nformational Note No. 2: Specific separation distances may be calcu lated from the sideflash equation in NFPA 780-20 17, Standard /or the Installation of Lightning Proleclion S)'Slems.

(4) Clearance. Supply service drops and sets of overhead service conductors of 0 volts to 750 volts running above and paralle l to communications and CATV type coaxial service drops shall have a minimum separation of 300 mm (12 in. ) at any point in the span, including the point of and at their attachment to the building, provided that the ungrounded conduc-

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70-665

800.100

ARTICLE 800 - GENERAL REQUIREMENTS FOR COMMUNICATIONS SYSTEMS

Part III. Grounding Methods 800.100 Cable and Primary Protector Bonding and Grounding. (A) Bonding Conductor or Grounding Electrode Conductor.

(1) In Buildings or Structures with an Intersystem Bonding Termination. If the building 01- su-ucture served has an inte1-system bonding termination as required by 250.94, the bonding conductor shall be connected to the intersystem bonding termination .

(1) Insulation. Th e bonding conductor or grounding electrode conducto1- shall be listed and shall be permitted to be insulated, covered, or bare. (2) Material. The bonding conductor or grounding electrode conductor shall be coppe1- or other corrosion-1-esistant conductive material, stranded or solid. (3) Size. The bonding conductor or grounding electrode conductor shall not be smaller than 14 AWG. The bonding conductor or grounding electrode conductor shall have a current-carrying capacity not less than the grounded metallic cable sheath member of the communications cable, the protected conductor of the communications cable, or the outer sheath of the coaxial cable, as applicable. The bonding conductor or grnunding electrode conductor shall not be required to exceed 6 AWG. (4) Length. The bonding conductor or grounding electrode conductor shall be as sh o1-t as practicable. In one- and twofami ly dwellings, the bonding conductor or grounding electrode conductor shall be as short as practicable, not to exceed 6.0 m (20 ft) in length. Informational Note: Similar bonding conductor or grounding electrode conductor length limitations applied at apartment buildings and commercial buildings help to reduce voltages that may be developed between the building's power and communications systems during lightning events.

E-.:ception: In one- and twofamily dwellings where it is not practicable to achieve an overall maximum bonding conductor or grounding electrode conductor length of 6.0 m (20 ft), a separate ground rod meeting the minimum dimensional ctite1ia of 800.JOO(B)(3)(2) or (B)(3)(3) shall be driven, the bonding conductor or grounding electrode conductor shall be connected to the ground rod in accordance with 800. JOO(C), and the gimmd rod shall be connected to the j>ower g1mmding electrode system in accordance with 800.JOO(D).

(5) Run in Straight Line. The bonding conductor or grounding elecu-ode conductor shall be run in as su-aight a line as practicable. (6) Physical Protection. Bonding conductors and grounding electrode conductors shall be protected where exposed to physical damage. 'Where the bonding conductor or grounding electrode conductor is installed in a metal raceway, both ends of the raceway shall be bonded to the contained conductor or to the same terminal or elecu-ode to which the bonding conductor or grounding electrode conductor is connected.

Informational Note: Informational Note Figure 800.lOO (B) (1) illusu-ates the connection of the bonding conductor in buildings or su-ucnires equipped with an intersystem bonding termination or a terminal b lock providing access to the building grounding means.

(2) In Buildings or Structures with Grounding Means. If an intersystem bonding termination is established, 250.94(A) shall apply. If the building or su-ucture served has no intersyste m bonding termination, the bonding conductor or grounding elecu-ode conductor shall be connected to the nea1-est accessible location on one of the following: (1) (2)

(3)

(4) (5) (6) (7)

The building or su-ucture grounding electrode syste m as covered in 250.50 The grounded interior metal water piping system, within 1.5 m (5 ft) from its point of entrance to the building, as covered in 250.52 The power service accessible means external to enclosures using the options identified in 250.94(A), Exception The non flexible metal power service raceway The service equipment enclosure The grounding electrode conductor or the grounding electrode conductor metal enclosure of the power service The grounding electrode conductor or the grounding electrode of a building or structure disconnecting means that is connected to a grounding electrode as covered in 250.32

A bonding device intended to provide a term ination point for the bonding conductor (intersystem bonding) shall not interfere with the opening of a n equipment e nclosw-e. A bonding device shall be mounted on nonremovable parts. A bonding device shall not be mounted on a door or cover even if the door or cover is nonremovable. For purposes of this section, the mobile home service equipment or the mobile home disconnecting means located within 9.0 m (30 ft) of the exterior wall of the mobile home it serves,

Service equipment

Communications equipment, protector or shield Bondingconductor

(B) Electrode. The bonding conductor or grounding electrode conductor shall be connected in accordance with 800.l OO(B)(l), (B)(2), or (B)(3) . Power service grounding electrode-conductor

lntersystem bonding termination or terminal block to building grounding means

~Grounding electrode Informational Note Figure 800.lOO(B)(l) Illustration of a Bonding Conductor in a Communications Installation. 70-666

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2020 Edition

ARTICLE 800- GENERAL REQUIREMENTS FOR COMMUNICATIONS SYSTEMS or at a mobile h ome disconnecting means connected to an elecu·ode by a grounding electrode conducto1· in acco1·dance with 250.32 and located within 9 .0 m (30 ft) of the exterior wall of the mobi.le home it serves, shall be considered to meet the requirements of this section . Informational Note: Informational Note Figure 800.100 (B)(2) illtL5trates the connection of the bonding conductor in buildings or structures equipped with an intersystern bonding termination or a terminal block providing access to the building grounding

800.106

Exception: At mobile homes as covered in 800.106. Informational Note No. 1: See 250.60 for connection to a lightning protection system. Informational Note No. 2: Bonding together of all separate e lectrodes limits potential differences between them and between their associated wiring systems.

800.106 Primary Protector Grounding and Bonding at Mobile Homes.

n1eans.

(3) In Buildings or Structures Without an futersystem Bonding Termination or Grounding Means. If the building or structure served has no intersystem bonding termination or grounding means, as described in 800.lOO (B) (2), the grounding electrode conducto1· shall be connected to one of the following: ( 1) (2)

(3)

To any one of the individual grounding elecu·odes desnibed in 250.52(A)(l), (A) (2), (A) (3), or (A) (4) If the building or structure served has no intersystem bonding termination or grounding means, as described in 800.l OO(B) (2) or (B) (3) (1), to any one of the individual grounding elecu·odes described in 250.52(A) (5), (A) (7), and (A) (8) For communications circuits covered in Article 805 or nenvork-powered broadband communications systems covered in Article 830, to a ground rod or pipe not less than 1.5 m (5 ft) in length and 12.7 mm (0.5 in.) in diameter, driven, where practicable, into permanently damp earth and separated from lightning protection system conductors, as covered in 800.53, and at least 1.8 m (6 ft) from e lecu·odes of other systems

Steam p ipes, hot water pipes, or lightning protection system conducto1·s shall not be empl oyed as grounding elecu·odes for protectors and grounded metallic members. (C) Electrode Connection. Connections to grounding elecn·odes shall comply with 250.70.

(D) Bonding of Electrodes. A bonding jumper not smaller than 6 AWG copper or equivalent shall be connected benveen the grounding electrode and power grounding electrode system at tl1e building or structure served where separate electrodes are used.

(A) Grounding. Grnunding shall comply with 800.106(A)(l) and (A) (2) . (I) Mobile Home Service Equipment. Where there is no mobile home service equipment located within 9 .0 m (30 ft) of the exterior wall of the mobile home it serves, grounding shall comply with one of the following: (1)

(2)

The primary protector grounding terminal; tl1e coaxial cable sh ield ground, or surge arrester grounding terminal; or the net\vork-powered broadband communications cable shield, network-powered broadband commw1ications cable metal lic members not used for communications or powering, a nd net\vork interface unit shall be connected to a groun din g electrode conductor or grounding electrode in accordance with 800. lOO(B) (3) . The non-current-carrying metallic members of o ptical fiber cables shall be connected to a grow1ding e lectrode in accordance with 770.106(A) (1) . The network terminal, if required to be grow1ded, s hall be connected to a grounding e lectrode in accordance with 800.1 06(A)(l)(l) . The grounding e lectrode s hall be bonded in accordance with 770.106(B) .

(2) Mobile Home Feeder Disconnecting Means. v\There there is no mobile home d isconne cting means grounded in accordance with 250.32 and located within 9 .0 m (30 ft) of the exterior wall of the mobile home it serves, grounding s hall comply with one of the following: (1)

The primary protector grounding terminal; the nenvorkpowered broadband communications cable shield, network-powered broadband communi cations cable metall ic members not used for communications or powering, and network interface unit s hall be conn ected to a grounding e lecu·ode in accordance with 800.lOO(B)

(2)

The non-current-carrying metallic members of optical fiber cables shall be connected to a grounding electrode in accordance with 770.106(A) (2). The nenvork terminal, if required to be grounded, shall be connected to a grounding ele ctrode in accordance with 800.1 06 (A) (2). The grounding electrode shall be bonded in accordance with 770.106(B) .

(3) .

Communications equipment, protector or shield

Service equipment

Grounding_ electrode conductor

t

Power service grounding electrodeconductor

Bonding conductor

~

~

Grounding electrodes

(B) Bonding. The p1·imary protector grounding terminal or grounding electrode, nenvork-powered b roadband communications cable grounding terminal, or net\vork interface u ni t grounding terminal shall be bonded together a nd conn ected to the metal frame o r available grounding terminal of the mobile home with a copper conductor not smaller than 12 AWG under either of the fo llowi ng conditions:

(1) (2)

vVhere there is no mobile home service equipment or disconnecting means as in 800.106(A) V\lhere the mobile home is supplied by cord and plug

Informational Note Figure 800.IOO(B)(2) Illustration of a Bonding Conductor in a Communications Installation. 2020 Edition

NATIONAL ELECTRICAL CODE

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800.110

ARTICLE 800 -

GENERAL REQUIREMENTS FOR COMMUNICATIONS SYSTEMS

Part IV. Installation Methods Within Buildings 800.110 Raceways, Cable Routing Assemblies, and Cable Trays. (A) Types of Raceways. Wires and cables shall be permitted to be installed in raceways that comply with either 800.1 lO(A) (1) or (A) (2) . Medium-power network-powered broadband communications cables shall not be permitted to be installed in raceways that comply with 800. llO (A) (2) . (I) Raceways Recognized in Chapter 3. Wires and cables shall be permitted to be installed in any raceway included in Chapter 3 . The raceways shall be installed in acco1-dance with the requirements of C hapter 3. (2) Communications Raceways. Wires and cables shall be permitted to be installed in plenmn communications raceways, riser communications raceways, and general-purpose communications raceways selected in accordance with Table 800.1 54(b), listed in accordance with 800.182, and installed in accordance with 800.11 3 and 362.24 through 362.56, where the requirements applicable to electrical nonmetallic tubing (ENT) apply. (3) Innerduct for Communications Wires and Cables, Coaxial Cables, or Network-Powered Broadband Communications Cables. Listed plenmn communications raceways, listed 1-iser commw1ications raceways, and listed general-purpose communications raceways selected in accordance with Table 800.1 54(b) shall be permitted to be installed as innerduct in any type of listed raceway permitted in Chapter 3.

(A) Listing. Wires, cables, cable routing assemblies, and communications raceways installed in buildings shall be listed. l!.xception: Cables installed in compliance with 805.48 ar 820.48 shall not be required to be listed.

(B) Ducts Specifically Fabricated for Environmental Air. The following wires and cables shall be permitted in ducts specifically fabricated for environmental air as described in 300.22(B) if they are directly associated with the air disu-ibution system:

(1) (2)

Informational Note: For information on fire protection of wiring installed in fabricated ducts, see NFPA 90A-20 18, Standard for the Installation of Air-Conditioning and Ventilating S)'st,ems.

(C) Other Spaces Used for Environmental Air (Plenwns). The following wires, cables, cable routing assemblies, and communications raceways shall be permitted in other spaces u sed fo1environmental air as described in 300.22(C):

(1) (2) (3) ( 4) (5) (6)

(B) Raceway Fill. The raceway fill requirements of Chapters 3 and 9 shall apply to medium-power network-powered broadband communications cables.

(7)

(C) Cable Routing Assemblies. Cables shall be permitted to be installed in plenum cabl e routing assemblies, riser cable routing assemblies, and general-pm-pose cable routing assemblies selected in accordance with Table 800 .1 54(c), listed in accordance with 800.1 82, and installed 111 accordance with 800.llO(C)(l) and (C) (2) and 800.11 3.

(8)

(1) Horizontal Support. Cable routing assemblies shall be supported whe1-e run horizontally at intervals not to exceed 900 mm (3 ft) and at each end or joint, unless listed for other support intervals. In no case shall the distance between suppo1-ts exceed 3 m (10 ft) .

(9)

(2) Vertical Support. Vertical runs of cable routing assemblies shall be supported at intervals not exceeding 1.2 m ( 4 ft), unless listed for other support intervals, and shall not have more than one joint between supports. (D) Cable Trays. Wires and cables and communications raceways shall be permitted to be installed in metal or listed nonmetallic cable u-ay systems. Ladder cable u-ays shall be permitted to support cable routing assemblies.

800.113 Installation of Wires, Cables, Cable Routing Assemblies, and Communications Raceways. Installation of wires, cables, cable routing assemblies, and communications raceways shall comply with 800.113(A) through (L). Installation of cable routing assemblies and communications raceways shall comply also with 800.110.

70-668

Plenum cables up to 1.22 m (4ft) in length Plemun cables, riser cables, general-purpose cables, and limited-use cables installed in raceways that are installed in compliance with 300.22(B)

Plenum cables Plenum communications raceways Plenum cable routing assemblies Plenum cables installed in plenum conununications raceways Plenum cables installed in plenum cable routing assemblies Plenum cables and ple num communications raceways supported by open metal cable tray systems Plemun cables, riser cables, general-purpose cables, limited-use cables, a nd conunun ications wires installed in raceways that are installed in compliance with 300.22(C) Plenum cables, riser cables, gene1-al-purpose cables, limited-use cables, plenum communications raceways, riser communications raceways, and general-purpose communications raceways supported by solid bottom metal cable trays with solid metal covers in other spaces used for environmental air (plenums) as described in 300.22(C) Plenum cables, riser cables, general-purpose cables, and limited-use cables installed in plenum communications raceways, riser communications raceways, and generalpurpose communications raceways supported by solid bottom metal cable trays with solid metal covers in other spaces used for environmental air (plenums) as described in 300.22(C)

Informational Note: For information on fire protection of wiring installed in other spaces used for environmental air, see NFPA 90A-2018, Standard for the Installation of Air-Conditioning and Ventilating Systems.

(D) Risers - Cables, Cable Routing Assemblies, and Communications Raceways in Vertical Runs. The following cables, cable routing assemblies, a nd communications raceways shall be permitted in vertical runs penetrating one or more floors and in vertical runs in a shaft: (1) (2) (3) (4)

Plenum and riser cables Plenum and riser commun ications raceways Plenum and riser cable routing assemblies Plenum and riser cables installed in: (a) Plenum commun ications raceways (b) Riser communications raceways (c) Plenum cable routing assemblies NATIONAL ELECTRICAL CODE

2020 Edition

ARTICLE 800- GENERAL REQUIREMENTS FOR COMMUNICATIONS SYSTEMS (d)

Riser cable routing assemblies

Informational Note: See 800.26 for firestop requirements for floor peneu-ations.

(E) Risers - Cables and lnnerducts in Metal Raceways. The following cables and innerducts shal l be permitted in metal raceways in a riser having firestops at each floor: Plenum cables, riser cables, general-purpose cables, and limited-use cables (2) Plenum, riser, and general-purpose communications raceways (3) Plenum cables, riser cables, general-purpose cables, and limited-use cables installed in: (a) Plenum communications raceways (innerduct) (b) Riser communications raceways (innerduct) (c) General-pm·pose communications raceways (innerduct) ( 1)

Informational Note: See 800.26 for firestop requirements for floor peneu-ations.

(F) Risers - Cables, Cable Routing Assemblies, and Communications Raceways in Fireproof Shafts. The following cables, cable routing assemblies, and comm unications raceways shall be permitted to be installed in fireproof r iser shafts having firestops at each floor:

Plenum cables, riser cables, general-purpose cables, and limited-use cables (2) Plenum, riser, and general-purpose communications raceways (3) Plenum, riser, and general-purpose cable routing assemblies (4) Plenum cables, riser cables, general-purpose cables, and limited-use cables installed in: (a) Plenum communications raceways (b) Riser communications raceways (c) General-purpose communications raceways (d) Plenum cable routing assemblies (e) Riser cable routing assemblies (f) General-purpose cable routing assemblies

( 1)

Plenum cables, riser cables, and general-purpose cables Plenmn, rise1-, and general-pm·pose comrnm1ications raceways (3) Communications wires, plenum cables, riser cables, and general-purpose cables installed in: (a) Plenmn communications raceways (b) Riser com munications raceways (c) General-purpose communications raceways

(1)

(2)

(I) Distributing Frames and Cross-Connect Arrays. The fo llowing wires, cables, cable routing assemblies, and communications raceways shall be permitted to be installed in distributing frames and cross-connect arrays:

Plenum cables, riser cables, general-purpose cables, and commun ications wires (2) Plenmn, riser, and general-purpose communications raceways (3) Plenum, rise1-, and general-purpose cable routing assemblies (4) Communications wfres, plenum cables, riser cables, and general-purpose cables installed in: (a) Plenmn communications raceways (b) Riser communications raceways (c) General-purpose communications raceways (d) Plenum cable routing assemblies (e) Riser cable routing assemblies (f) General-purpose cable routing assemblies (1)

(J) Other Building Locations. The following wires, cables, cable routing assemblies, and communications raceways sha ll be permitted to be installed in building locations other than the locations covered in 800.113(B) through (I): (1)

(2) (3) ( 4) (5)

Informarional Note: See 800.26 for firestop requirements for floor peneu-ations.

(G) Risers - One- and Two-Family Dwellings. The following cables, cable routing assemblies, and communicatio ns raceways shall be permitted in one- and two-family dwellings: Plenum cables, riser cables, and general-purpose cables Limited-use cables less than 6 mm (0.25 in. ) in diameter Plenum, rise1-, and general-purpose communications raceways (4) Plenum, riser, and gene1·al-purpose cable routing assemblies (5) Plenum cables, riser cables, and general-purpose cables installed in: (a) Plenum communications raceways (b) Riser communications raceways (c) General-pm·pose commun ications racevr.1ys (d) Plenum cable routing assemblies (e) Riser cable routing assemblies (f) General-purpose cable routing assemblies

(6)

(1) (2) (3)

(H) Cable Trays. The following wires, cables, and communications raceways shall be permitted to be supported b y cable trays:

2020 Edition

NATIONAL ELECTRICAL CODE

800.113

(7)

(8)

Plenum cables, riser cables, and general-purpose cables Limited-use cables with a maximum of 3 m ( 10 ft) of exposed length in nonconcealed spaces Plenum, rise1-, and general-purpose communications raceways Ple num, riser, and general-purpose cable routing assemblies Communications wires, plenum cables, riser cables, and general-purpose cables installed in the following: (a) Plenum communications raceways (b) Riser communications raceways (c) General-purpose corrununications raceways Plenum cables, riser cables, and general-purpose cables instal led in the following: (a) Plenum cabl e routing assemblies (b) Riser cable routing assemblies (c) General-purpose cable routing assemblies Communications wires, plenum cables, riser cables, general-purpose cables, and limited-use cables installed in raceways recognized in C hapte r 3 Type CMUC under-carpet communications wires and cables installed u nder carpet, modular floo ring, and planks

(K) Multifamily Dwellings. The following cables, cable routing assemblies, and commtmi cations raceways shal l be permitted to be installed in multifamily dwellings in locations other than the locations covered in 800.113(8) th rough (G): (1) (2)

(3)

Plenum cables, riser cables, and general-purpose cables Limited-use cables less than 6 mm (0.25 in .) in d iameter in nonconcealed spaces Plenmn, riser, and general-purpose communications raceways

70-669

800.113 (4) (5)

(6)

(7)

(8)

ARTICLE 800 -

GENERAL REQUIREMENTS FOR COMMUNICATIONS SYSTEMS

Plenum, riser, and general-purpose cable routing assemblies Communications wires, plenum cables, riser cables, and general-pmpose cables installed in the following: (a) Plenum communications raceways (b) Riser communications raceways (c) General-purpose communications raceways Plenwn cables, riser cables, and general-purpose cables installed in the following: (a) Plenum cable routing assemblies (b) Riser cable routing assemblies (c) General-purpose cable routing assemblies Communications wires, plenum cables, riser cables, general-pw·pose cables, and limited-use cables installed in raceways recognized in Chapter 3 Type CMUC under-carpet communications wires and cables installed under carpet, modular flooring, and planks

(L) One- and Two-Family Dwellings. The following wires, cables, cable routing assemblies, and communications raceways shall be permitted to be installed in one- and two-family dwellings in locations other than the locations covered in 800.l 13(B) through (F): (1)

(2) (3) (4)

(5)

(6)

(7)

(8)

(9)

Plenum cables, riser cables, and general-purpose cables Limited-use cables less than 6 mm (0.25 in.) in diameter Plenum, rise1~ and general-purpose communications raceways Plenum, riser, and general-purpose cable routing assemblies Communications wires, plenum cables, riser cables, and general-pw·pose cables installed in the following: (a) Plenum communications raceways (b) Riser communications raceways (c) General-purpose communications raceways Plenum cables, riser cables, and general-purpose cables installed in the following: (a) Plenum cable routing assemblies (b) Riser cable routing assemblies (c) General-purpose cable routing assemblies Communications wires, plenum cables, 1·iser cables, general-purpose cables, and limited-use cables installed in raceways recognized in Chapter 3 Type CMUC under-carpet communications wires and cables installed under carpet, modular flooring, and planks H ybrid power and communications cable listed in accordance with 805.1 79(F)

800.154 Applications of Listed Communications Wires, Cables, and Raceways, and Listed Cable Routing Assemblies. Permitted and nonpermitted applications of listed communications wires, cables, coaxial cables, network-powered broadband communications system cables and raceways, and listed cable routing assemblies, shall be in accordance with one of the following: ( 1) (2) (3)

Listed communications wires and cables as indicated in Table 800.1 54(a) Listed commtmications raceways as indicated in Table 800.1 54(b) Listed cable routing a5semblies as indicated in Table 800.1 54(c)

800.179 Plenum, Riser, General-Purpose, and Limited Use Cables. Plenum, rise1·, general-purpose, and limited-use cables shall be listed in accordance with 800.179(A) through (D) and shall have a temperature rating of not less than 60°C (l 40°F) . T he temperature rating shall be marked on the jacket of cables that have a temperature rating exceeding 60°C (140°F) . The cable voltage rating shall not be marked on the cable. (A) Plenum Cables. Type CMP communications plenum cables, Type CATVP com munity antenna television plenum coaxial cables, and Type BLP netwurk-powered broadband communication low-power plenum cables shall be listed as being suitable for use in ducts, plenums, and other spaces used for environmental air and shall also be listed as having adequate fire-resistant and low smoke-producing characteristics. Informational Nore: One method of defining a cable that is lowsmoke-produdng cable and fire-resistant cable is rhar the cable exhibits a maximum peak optical density of 0.50 or less, an average optical density of 0.15 or less, and a maximum flame spread distance of 1.52 m (5 fr) or less when rested in accordance with NF'PA 262-2019, Standard M ethod of Tesl for flam e Travel and Smoke of Wires and Cab/Rs for Ure in Air-Handling Spaces.

(B) Riser Cables. Type CMR communications riser cables, Type CATVR community ante n na television riser coaxial cables, Type BMR network-powered broadband communications medium-power riser cables, and Type BLR networkpowered broadband communications low-power riser cables shall be listed as being suitable for use in a vertical run in a shaft or from floor to floor and shall also be listed as having fire-resistant characteristics capable of preve n ting the carrying of fire from floor to floo r. Informational Nore: One method of defining fire-resistant c haracteristics capable of prevenring the carrying of fire from fl oor ro floor is that rhe cables pass rhe requirements of ANSI/U L 1666-2011, Slandm·d Tesl for Harne Propagation Heighl of Eleclrical and Oj1lical-Fiber Cab!R Inslalled Vertically in Shajls.

(C) General-Purpose Cables. Type CM commun icati ons general-purpose cables, Type CATV community antenna television coaxial general-purpose cables, Type BM network-powered broadband communications medium-power general-purpose cables, and Type BL network-powered broadband conununications low-power general-purpose cables shall be listed as being suitable for general-purpose use, with the exception of risers and plenums, and sha ll also be listed as being resistant to the spread of fire. Informational Nore: One method of defining resislanl lo lhe sj;read offire is that the cables do not spread fire ro the top of the tray in the "UL Flame Exposure, Vertical Flame Tray Test" in ANSI/ UL 168.~-2010, Standard for Safely for Verlical-Tm)' 1-lrePivjmgalion and Smoke-Re/Rase Tesl for b"kclrical and Oj1lical-Fiber Cables. The smoke measurements in the rest method are nor applicable. Another method of defining resislanl lo the sjmad of fire is for the damage (char length) not ro exceed 1.5 m (4 fr

11 in.) when performing the CSA "Vertical Flame Test - Cables in Cable Trays," as described in CSA C22.2 No. 0.3-09, Tesl Melhods for Elecl1ical Wires and Cab/Rs.

The permitted applications shall be subject to the installation requirements of800.11 0 and 800.11 3.

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ARTICLE 800- GENERAL REQUIREMENTS FOR COMMUNICATIONS SYSTEMS

800.179

Table 800.154(a) Applications of Listed Communications Wires, Cables, and Network-Powered Broadband Communications System Cables in Buildings Wire and Cable Type Hybrid Power and

BMR

BM

LimitedUse

Undercarpel

BMU, BLU

Communications

Riser

GeneralPurpose

Communications

Plenum

Cables

Wires

y

N

N

N

N

N

N

N

N

N

y

y

y

y

y

y

N

N

N

y

y

N

N

N

N

N

N

N

N

N

y

y

y

y

y

y

N

N

N

y

y

N

N

N

N

N

N

N

N

N

y

N

N

N

N

N

N

N

N

N

Supported by open metal cable trays

y

N

N

N

N

N

N

N

N

N

Supported by solid bottom metal cable trays with solid

y

y

y

y

y

y

N

N

N

N

In vertical runs

y

y

y

N

N

N

N

N

N

N

In metal raceways

y

y

y

y

y

y

N

N

N

N

In fireproof shafts

y

y

y

y

y

y

N

N

N

N

In p lenum comn-1unications raceways

y

y

N

N

N

N

N

N

N

N

y

y

N

N

N

N

N

N

N

N

y

y

N

N

N

N

N

N

N

N

y

y

N

N

N

N

N

N

N

N

y

y

y

y

y

y

N

N

y

N

Applicatlons In ducts specifically fabricated for environmenta l air as described in 300.22(B)

In fabricated ducts

ln metal raceway that complies with 300.22(B)

In other spaces used for

In other spaces used for

environmenta l

cn\~ronmental

air (plenums)

air

as described in

300.22(C)

In metal raceway that complies with 300.22(C)

In p lenum communications

raceways In plenum cable rou ting

assemblies

mer.al covers

ln i;sers

In plenum cable routing

assemblies Jn riser communications

raceways In 1iser cable routing as.o;;emblies

In one- and twofamily dwellings

(continues)

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800.179

ARTICLE 800 - GENERAL REQUIREMENTS FOR COMMUNICATIONS SYSTEMS

Table 800.154(a)

Continued Wire and Cable Type

P lenum

Riser

BMR

GeneralPurpose

BM

LimitedUse

U ndercarpel

BMU, BLU

Hybrid Power and Communicatfons Cables

Gen eral

y

y

y

y

y

y

N

N

N

N

In one- and n"·o-

y

y

y

y

y

y

y

N

y

N

In mul tifam ily dwellings

y

y

y

y

y

y

y

N

N

N

In nonconcealcd spaces

y

y

y

y

y

y

y

N

N

N

Supported by cable trays

y

y

y

y

y

N

N

N

N

N

Under carpet, modular flooring, and planks

N

N

N

N

N

N

y

N

N

N

In distributing frames and cross-connect

y

y

N

y

N

N

N

N

N

y

In rigid metal conduit ( RMC) and intermediate metal conduit (IMC)

y

y

y

y

y

y

y

y

y

y

In an y raceway recognized in Chapter 3

y

y

y

y

y

y

N

N

N

y

In plenum comn1unications

y

y

N

y

N

N

N

N

N

y

In plenum cable routing assemblies

y

y

N

y

N

N

N

N

N

y

In riser commun ications raceways

y

y

N

y

N

N

N

N

N

y

In riser cable routing assemblies

y

y

N

y

N

N

N

N

N

y

In generalpurpose comtnunicatio ns raceways

y

y

N

y

N

N

N

N

N

y

y

y

N

y

N

N

N

N

N

y

Applications Within buildings in other tha n air-handling

spaces and risers

family dwellings

Communications Wires

arrays

raceways

In gen eralpurpose cable routing assc1nblies

Note: An "N" in the table indicates that the cable type shall not be permitted to be installed in the application. A "Y" indicates that the cable type shall be permitted to be installed in the application subject to d1e limitations described in 800.113. The Riser column includes all riser cables except BMR, and the General-Purpose column includes a ll general-purpose cables except BM. Informational Note No. l: Pan IV of Article 800 covers installation med10ds wid1in buildings. This table covers the applications of listed communications wires, cables, and raceways in buildings . See the definition of Point of Entrance in 800.2. Informational Note No. 2: For information on the restrictions to th e installation of communications cables in fabricated ducts, see 800.11 3(B).

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ARTICLE 800- GENERAL REQUIREMENTS FOR COMMUNICATIONS SYSTEMS

800.179

Table 800.154(b) Applications of Listed Communications Raceways in Buildings

Applications In ducts specifically fabricated for environmental air as described in 300.22(B) In other spaces used for environmemal air (plenums) as described in 300.22(C)

In risers

Within buildings in other than air-handling spaces and risers

Listed Communications Raceway Type Plenum

Riser

General-Purpose

In fabricated ducts

N

N

N

In metal raceway that complies with 300.22(B)

N

N

N

l n other spaces used for environmental air

y

N

N

ln metal raceway that complies with 300.22(C)

y

y

y

l n p lenum cable routing assemblies

N

N

N

Supported by open metal cable trays

y

N

N

Supported by solid bottom metal cable trays with solid metal covers

y

y

y

In vertical runs

y

y

N

l n metal raceways

y

y

y

In fireproof shafts

y

y

y

In p lenum cable routing assemblies

N

N

N

In riser cable routing assemblies

N

N

N

In one- and two-family dwellings

y

y

y

General

y

y

y

In one- and two-family dwellings

y

y

y

In multifamily dwellings

y

y

y

ln nonconcealed spaces

y

y

y

Supported by cable trays

y

y

y

Under carpet, modular flooring, and p lanks

N

N

N

In distributing frames and cross-connect arrays

y

y

y

In any raceway recognized in Chapter 3

y

y

y

In p lenum cable routing assemblies

N

N

N

In riser cable routing assemblies

N

N

N

In general-purpose cable routing assemblies

N

N

N

Note: An "N" m the table md1cates that the commun1cauons raceway type shall not be permmed to be mstalled m the apphcauon. A "Y" md1cates that the communications raceway type shall be permitted to be installed in the application, subject to the limi tations described in 800.110 and 800.113.

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800.179

ARTICLE 800 - GENERAL REQUIREMENTS FOR COMMUNICATIONS SYSTEMS

Table 800.154(c) Applications of Listed Cable Routing Assemblies in Buildings Listed Cable Routing Assembly Type Applications In ducts specifica lly fabricated for environmental air as described in 300.22(B) Jn other spaces used for environmental a ir (ple nums) as described in 300.22(C)

In risers

Within buildings in other than a ir-handling spaces and risers

Plenum

Riser

General-Purpose

In fabric.·ued duccs

N

N

N

In metal raceway that complies with 300.22(B)

N

N

N

In other spaces used for environmental air

y

N

N

In meta! raceway that complies with 300.22(C)

N

N

N

In plenum communications raceways

N

N

N

Supported by open metal cable trays

y

N

N

Supported by solid bottom metal cable trays with solid metal covers

N

N

N

Jn vertical runs

y

y

N

In metal raceways

N

N

N

In fireproof shafts

y

y

y

In p lenum communications raceways

N

N

N

In riser communications raceways

N

N

N

In one- and two-fam ily dwellings

y

y

y

General

y

y

y

In one- and two-family dwellings

y

y

y

In multifamily dwellings

y

y

y

In nonconcealed spaces

y

y

y

Supported by cable trays

y

y

y

Unde r carpet, modular flooring , and p lanks

N

N

N

Jn d istributing frames and cross-connect arrays

y

y

y

In any raceway recognized in Chapter 3

N

N

N

Jn ple num communications raceways

N

N

N

In riser communications raceways

N

N

N

Jn general-purpose communications raceways

N

N

N

Note: An "N" in the table indicates that the cable routing assembly type shall not be permitted to be installed in the application. A "Y" indicates that the cable routing assembly type shall be permitted to be installed in the application subject to the limitations described in 800.11 3.

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ARTICLE 805-COMMUNICATIONS CIRCUITS (D) Limited-Use Cables. Type CMX limited-use commun ications cables, Type CATVX limited-use commtmity antenna television coaxial cables, and Type BLX limited-use networkpowered broadband low-power cables shall be listed as being suitable for u se in dwellings and for use in raceway and shall a lso be listed as being resistant to flame spread.

Informational Note: One method of determining that cable is resistant to flame spread is by resting the cable to the VW-1 (vertical-wire) flame rest in ANSI/ UL 1581-2017, Reference Standanl for Elecl1ical Wims, Cables and Flexible Cords.

Part V. Listing Requirements 800.180 Grounding Devices. Where bonding or grounding is 1-equired, devices used to connect a shield, a sheath, or noncurrent-carrying metallic members of a cable to a bonding conductor or grounding electrode conductor shall be listed or b e part of listed equipment. 800.182 Cable Routing Assemblies and Communications Raceways. Cable routing assemblies and communi cations raceways shall be listed in accordance with 800.1 82(A) through (C) . Cable routing assemblies shall be marked in accordance with Table 800.182(a) . Comm unications raceways shall be marked in accordance with Table 800.1 82(b ) . Informarional Note: For information on listing requirements for both communications raceways and cable routing assemblies, see ANSI/ UL 2024-5-2015, Cable Routing Assemblies and Conmwnications Raceiva)'S.

(A) Plenum Cable Routing Assemblies and Plenum Communications Raceways. Plenum cable routing assemblies and plenum communications raceways shall be listed as having adequate fire-resistant and low-smoke-produ cing c haracteristics.

Informational Note No. 1: One med1od of defining cable routing assemblies and communications raceways drnt have adequate fire-resistant and low-smoke-producing characteristics is d1at d1ey exhibit a maximum flame spread index of 25 and a maximum smoke developed index of 50 when tested in accordance with ASTM E84-15a, Standard Test Method for Sttr[ace Bttrning Characteristics of Building MalPrials, or ANSI/ UL 72 3-2013, Slandanl Test Method for Swface Bttrning Charac!Pristics of Building Ma!Prials.

805.2

Informational Note No. 2: Another med10d of defining communications raceways that have adequate fire-resistant and lowsmoke-producing characteristics is that they exhibit a maximum peak optical density of 0.50 or less, an average optical density of 0.15 or less, and a maximtm1 flame spread distance of 1.52 m (5 ft) or less when tested in accordance with NFPA 262-2015, Standard Method of Test for Flame Travel and Smoke of Wires and Cables for Use in Air-Handling SjJaces.

Informational Note No. 3: See 4.3.11.2.6 or 4.3.11.5.5 of NFPA 90A-2015, Standanl for the l nslallation of Air-Conditioning and Ventilating Systems, for information on materials exposed to the airflow in ceiling ca\~ty and raised floor p lenums.

(B) Riser Cable Routing Assemblies and Rise r Communications Raceways. Riser cable routing assemblies a nd r iser communicati ons raceways shall be listed as having adequ ate fire-resistant characteristics capable of preventing the carryi ng of fire from floor to floor. Informational Note: One method of defining fire-resistant characteristics capable of preventing d1e carrying of fire from floor to floor is d1at the cable routing assemblies and communications raceways pass the requirements of ANSI/ UL 1665-2011 , Standard Test for Flame Propagation Height of Elect1ical and OpticalFiber Cable Installed Vertically in Shafts.

(C) General-Purpose Cable Routing Assemblies and GeneralPurpose Communications Raceways. General-purpose cable routing assemblies a nd general-purpose communications raceways shall be listed as being resistant to the spread of fire .

Informational Note: One method of defining resistant to the spread of fire is that the cable routi ng assemblies and communications raceways do not spread fire to the top of the tray in d1e "UL Flame Exposure, Vertical Flame Tray Test" in ANSI/ UL 1685-2011, Standani for Safety for Vertical-1i·a)' Fire-Propagation and Smoke-Release Test for Electrical and Optical-l~ber Cables.

ARTICLE805 Communications Circuits Part I. General 805.1 Scope. This article covers communications circuits and equipment.

Table 800.182(a) Cable Routing Assembly Markings Type Ple num Cable Routing Assembly Riser Cable Ro uting Assembly General-Purpose Cable Routing Assembly

Marking Plenum Cable Routing Assembly Riser Cable Routing Assembly General-Purpose Cable Routing Assembly

Table 800.182(b) Communications Raceway Markings Type Plenum Communications Raceway Riser Communications Raceway General-Purpose Communications Raceway

2020 Edition

805.2 Definitions. The definitions in this section sh a ll apply only within Articles 805 and 840. Cable. A factory assembly of two or more conductors having an overall covering. Communications Circuit Integrity (CI) Cable. Cable used in communicati ons systems to e n sure continued operation of critical circuits during a specified time under fire conditions. Wire. A facto1y a5sembly of one or mo1-e insulated conductors without an overall covering.

Marking Plenum Communications Raceway Riser Communications Raceway General-Purpose Comm unications Raceway

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805.18

ARTICLE 805-COMMUNICATIONS CIRCUITS

805.18 Installation of Equipment. Equipment eleca-ically connected to a commw1ications netwo1-k shall be listed in accordance with 805.1 70 . Exception: This listing requirement shall not apply to test equipment that is intended for tempora1)' connection to a telecommunications network by qualified persons during the course of installation, maintenance, or repair of telecommunications equipment or systems.

Part II. Wires and Cables Outside and Entering Buildings 805.4 7 Underground Communications Wires and Cables Entering Buildings. Underground communications wires and cables entering buildings shall comply with 805.47(A) and (B ). The 1-equirements of 310.lO(C) shall not apply to com mun ications wires and cables. (A) Underground Systems with Electric Light, Power, Class 1, or Non-Power-Limited Fire Alarm Circuit Conductors. Underground communications wires and cables in a raceway, handhole enclosure, or manhole containing electric lig ht, power, Class 1, or non-power-limited fire alarm circuit conductors shall be in a section separated from such conductors by means of brick, concrete, or tile partitions or by means of a suitable barrier. (B) Underground Block Distribution. Where the entire sa-eet circuit is run underground and the circuit within the block is placed so as to be free from the likelihood of accidental contact with electric light or power c ircui ts of over 300 volts to ground, the insulation requiremen ts of 805.50 (A) and 805.50 (C) shall not apply, insulating supports shall not be required for the conductors, and bushings shall not be required where the conductors enter the building. 805.48 Unlisted Cables Entering Buildings. Unlisted ou~5ide plant communications cables shall b e permitted to be installed in building spaces other than risers, ducts used for environmental air, plenums used for environmental a ir, and other spaces used for environmental a ir, where the length of the cable within the building, measured from its point of entrance, does n ot exceed 15 m (50 ft) and the cable enters the building from the outside and is terminated in an enclosure or on a listed primary protector. The point of entrance shall be permitted to be extended from the penetration of the external wall or floor slab by continuously enclosing the enu-ance cables in rigid metal conduit (RMC) or intermediate metal conduit (IMC) to the point of e mergence. Informational Note No. l: Splice cases or terminal boxes, both metallic and p lastic types, are typically used a~ enclosures for splicing or terminating telephone cables. Informational Note No. 2: This section limits the length of un listed outside p lant cable to 15 m (50 ft), while 805.90 (B) requires that the primary protector be located as close as practicable to the point at which the cable enters the bui lding. Therefore, in installations requiring a primary protecwr, the outside p lant cable may not be permitted to extend 15 m (50 ft) into the build ing if it is practicable to p lace the primary protector closer than 15 m (50 ft) to the point of entrance.

805.50 Circuits Requiring Primary Protectors. C ircui ts that require primary p1-otectors a5 provided in 805.90 shall comply with 805.50 (A),805 .50 (B), and 805.50 (C) . (A) Insulation, Wires, and Cables. Communi cations wires and cables without a metalli c shield, nmning from the last outdoor

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support to the primary protector, shall be listed in accordance with 805.1 73. (B) On Buildings. Commun ications wires and cables in accordance with 805.50 (A) shall be separated at least 100 mm (4 in. ) from e lectric light or power conductors not in a rnceway or cable or be permanently separated from conductors of the other systems by a continuous and fi rmly fixed nonconductor in addition to the insulation on tlle wires, such as porcela in tubes or flexible tubing. Communications wires and cables in accordance with 805.SO(A) exposed to accidental contact with elecu-ic light and power conductors opernting at over 300 volts to ground and attached to buildings sha ll be separated from woodwork by being supported o n glass, porcelain, or o ther insulating material.

Exception: Separation fivm woodwork shall not be required where fuses are omitted as p1vvided for in 805. 90(A )(1 ), or where conductors are used to extend circuits to a building from a cable having a gmunded metal sheath.

(C) Entering Buildings. Where a primary protector is installed inside the building, the communications wires a nd cables sha ll enter the building either throug h a noncombustible, nonabsorb ent insulating bushing or through a metal raceway. The insulating bushing shall not be l·equired where the e ntering com munications wires a nd cables (1) are in metal-sheathed cable, (2) pass through masonry, (3) meet the requirements of 805.50(A) and fuses a1-e omitted as provided in 805 .90(A)(l), or (4) meet tl1e requirements of 805.50(A) a nd are used to extend circuits to a building from a cable having a grou nded metallic sheath . Raceways or bushings shall slope upward fro m the o utside 01~ where this can not be d one, drip loops shall be formed in the communications wires and cables immediately before they enter the building. Raceways shall be equipped wi th an approved service head. More than one communications wire and cable sha ll be pe rmitted to enter through a single raceway or bushing. Conduits or other metal raceways located ahead of the primary protector shall b e grounded.

Part III. Protection 805.90 Protective D evices. (A) Application. A listed p ri mary protector shall be provided on each c ircuit run partly or e ntirely in aerial wire or aeria l cable not confined within a bl ock. Also, a listed primary protector shall be provided on each circ uit, aerial or unclergrotmd, located within the block containing th e building served so as to be exposed to accidental contact with e leca-ic light or power conductors operating at over 300 volts to ground. In additio n, where there exists a lig htning exposure, each interbuilcling circuit on a p1-emises shall be protected by a listed primary protector at each encl of the interbuilding c ircuit. Installa tio n of primary protectors shall a lso comply witl1 110.3(B) . Informational Note No. 1: On a circuit not exposed to accidental contact with power conductors, providing a listed primary protector in accordance with this article h e lps protect against other hazards, such as lightning and above-normal voltages induced by fau lt currents on power circuits in p roximiry to the communications circuit. Informational Note No. 2: lnterbuilding circuits are considered to have a lightning exposure unless one or more of the following conditions exist:

NATIONAL ELECTRICAL CODE

2020 Edi tion

ARTICLE 805-COMMUNICATIONS CIRCUITS (1) (2)

(3)

Circuits in large metropolitan areas where buildings are close together and sufficiently high to intercept lightning. Interbuilding cable runs of 42 m ( 140 ft) or less, directly buried or in underground conduit, where a continuous metallic cable shield or a continuous metal conduit containing the cable is connected to each building grounding electrode system . Areas having an average of five or fewer thunderstorm days per year and earth resistivity of less than 100 ohmmeters. Such areas are found a long the .Pacific coast.

Informational Note No. 3: For information on lightning protection systems, see NFPA 780-2017, Standard for the Installation of Lightning Protection S)'sUms.

(I) Fuseless Primary Protectors. Fuseless-type primary protectors sha ll be permitted under any of the conditions given in 805.90(A)(l)(a) through (A)(l)(e) .

(a) Where condu ctors enter a building through a cable with grounded metallic sheath member(s) and where the conductors in the cable safely fuse on a ll currents greater than the current-carrying capacity of the primary protector and of the primary protector bonding conductor or grounding electrode conducto r (b) Where insulated conductors in accordance with 805.50(A) are used to extend c ircuits to a building from a cable with an effectively grounded metallic sheath member(s) and where the conductors in the cable or cable stub, or the connections betvveen t he insulated conductors and the plant exposed to accidental contact with electric light or power conductors operating at greater than 300 volts to ground, safely fuse on all currents greater than the current-carrying capacity of the primary protector, or the associated insulated conductors and of the primary protector bonding conducto1· or grou nding e lectrode conductor (c) Where ins ulated conductors in accordance with 805.50(A) or (B) are used to extend circuits to a building from other than a cabl e with metallic sheath member(s), where (1) the primary protector is listed as be ing suitable for this purpose for app lication with circuits extending from other than a cable with metallic sheath members, and (2) the connections of the insulated conductors to the plant exposed to accidental contact with e lecu·ic lig ht or powe1· conductors operating at greater than 300 volts to ground or the conductors of the plant exposed to accidental contact with electric light or power conductors operating at greater than 300 volts to ground safely fuse on all currents g reater than the currentcarrying capacity of the primary protector, or associated insulated conductors and of the primary protector bonding condu ctor or grounding electrode conductor (d) Where insulated cond uctors in accordance with 805.50(A) are used to extend circuit~ aerially to a building from a buried or underground circuit that is unexposed to accidental contact with electric light or power conductors operating at greater than 300 volts to ground (e) Where insulated condu ctors in accordance with 805.50(A) are used to extend circuits to a building from cable with an effectively grounded m etallic sheath member(s), and where ( 1) the combination of the primary protector and insulated conductors is listed as being suitable for this purpose for application with circuits extending from a cable with an effectively grounded metallic sheath member(s), and (2) the insulated conductors safely fuse on a ll currents greater than the current-carrying capacity of the p1·imary protector and of the

2020 Edition

NATIONAL ELECTRICAL CODE

805.93

primary protector bondi ng conducto r or grounding elecu-ode conductor Informational Note: Section 9 of ANSI/ IEEE C2-2012, National Ewctrical Sa/et)' Code, provides an example of methods of protective grounding that can achieve effective grounding of communications cable sheaths for cables from which communications circuits are extended.

(2) Fused Primary Protectors. Where the requirements listed under 805.90(A) (1 ) (a) through (A)(l) (e) are not met, fosedtype primary protectors shall be used . Fused-type primary protectors shall consist of an arrester connected between each line condu ctor and ground, a fose in series with each line conductor, and an appropriate mounting arrangement. Primary protector terminals sha ll be marked to indicate line, instrument, and ground, as a pplicable. (B) Location. The primary protector shall be located in, on, or immediately adjacent to the strucn1re or building served a nd as close as practicable to the point o f enu·ance . For purposes of this section, p rimary protectors located at mobile home service eq uipme n t within 9.0 m (30 ft) of the exterior wall of the mobile home it serves, or at a m obile home disconnecting means connected to an e lectrode by a grounding electrode conductor in accordance with 250.32 and located within 9.0 m (30 ft) of the exterior wall of the mobile home it serves, shall be considered to meet th e requirements of this section. Informational Note: Selecting a primary protector location to achieve the shortest practicable primary protector bonding conductor or grounding electrode conductor helps limit potential differences between communications circuit~ and other metallic systems.

(C) Hazardous (Qassified) Locations. The primary protector shall not be located in any hazardous (classifi ed) locations, as defined in 500.5 and 505.5, or in the vicinity of easily ignitible material.

Exception: As permitted in 501.150, 502.150, and 503.150. (D) Secondary Protectors. \\There a secondary protector is installed in series with the indoor communications wire and cable b etween the primary protector a nd the equipment, it shall be listed for the purpose in accordance with 805.170(B) . Informational Note: Secondary protectors on circuits exposed to accidental contact with electric light or power conduct.ors operating at greater than 300 vo lts to ground are not intended for use without primary protectors.

805.93 Grounding, Bonding, or Interruption of Non-CurrentCarrying Metallic Sheath Members of Communications Cables. Communications cables e ntering the building or term ina ting on the outside of the building shall comply with 805.93(A) o r (B) . (A) Entering Buildings. In installations where th e communications cable enters a building, the metallic sheath m embers of the cable shall be g rounded 01· bonded as specified in 800.1 00 or interrupted by an insulating joint or equivalent device. The grounding, bonding, or in terruption shall b e as close as practicable to the point of enu·ance.

(B) Terminating on the Outside of Buildings. In installations where the communications cable is terminated on the outside of the building, the metallic sh eath m embers of th e cable shall be grounded or b onded as specified in 800.100 or in terrupted

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805.133

ARTICLE 805-COMMUNICATIONS CIRCUITS

by an insulating joint or equivalent device. The grounding, bonding, or interruption shall be as close as practicable to the point of termination of the cable.

Part IV. Installation Me thods Within Buildings 805.133 Installation of Communications Wires, Cables, and Equipment. Communications wires and cables from the protector to the equipment or, where no protector is required, commun icatiorL~ \vires a nd cables attached to the outside or inside of the building shall comply \vith 805.1 33(A) and 805.1 33( B) (A) Separation from Other Conductors. (1) In Raceways, Cable Trays, Boxes, Cables, Enclosures, and Cable Routing Assemblies. (a) Other Circuits. Communications cables shall be permitted in the same raceway, cable tray, box, enclosure, or cable routing assembly with cables of any of the follmvi ng:

(1)

(2) (3) (4 ) (5)

Class 2 and Class 3 remote-conu·ol, signaling, and powerlimited circuits in compliance \vith Article 645 or Parts I and III of Article 725 Power-limited fit·e alarm systems in compliance \vith Parts I and III of Article 760 Nonconductive and conductive optical fiber cables in compliance \vith Parts I and V of Article 770 Community antenna television and radio disu-ibution systems in compliance with Parts I and V of Article 820 Low-power netwo1·k-powered b1·oadband communi cations circuits in compliance \vi th Parts I and V of Article 830

(b) Class 2 and Class 3 CircuiL5. Class l circuits shall not be run in the same cable \vith commun ications circuits. Class 2 and Class 3 circuit condu ctors shall be permitted in the same listed communications cable with communications circ uits. (c) Electric Light, Powe1; Class 1, Non-Power-Limited Fire Alarm, and Medium-Power Network-Powered Broadband Communications Circ-uits in Raceways, Compartments, and Boxes. Communi cations conducto1·s shall not be placed in any raceway, comparunent, outlet box, junction box, or similar fitting \vi th conductors of elecu·ic light, power, Class 1, non-power-limited fire alarm, o r medium-power network-powered broadband communications circuits.

Exception No. 1: Section 805.JJJ(A)(l )(c) shall not apply if all of the conductors of electric light, powm; Class 1, non-powe1~limited fire alarm, and medium-power network-powered broadband communications circuits are separated from all of the conductors of communications circuits by a permanent barrier or listed divider. Exception No. 2: Power conductors in outlet boxes, junction boxes, or similar fittings or compartments where such conductors are introduced solef:y for power supply to communications equipment. The power circuit conductors shall be routed within the enclosure to maintain a minimum of 6 mm ( 11, in.) sqxiration from the communications circuit conductors.

Exception No. 1: Section 805.133(A)(2) shall not apply where eithm· (1) all of the conductors of the electric light, powe1; Class 1, non-powe1~ limited fire alarm, and mediuin-powm· network-powered lmwdband communications circuits are in a raceway or in metal-sheathed, metalclad, nonmetallic-sheathed, Type AC, or Type UF cables, or (2) all of the conductors of communications circuits are encased in raceway. .Exception No. 2: Section 805.133(A)(2) shall not apply whm·e the communications wires and cabl.es are permanently separated from the conductors of electric light, powe1; Class 1, non-power-limited fire alarm, and medium-power network-powered broadband communications circuits by a continuous and firml')' fixed nonconduct01; such as porcelain tubes 01· flexible tubing, in addition to the insulation on the wire. (B) Support of Communications Wires and Cables. Raceways shall be used for their intended purpose. Com munications wires and cables shall not be strapped, taped, or attached by any means to tl1e exterior of any raceway as a means of suppon.

Exception: Overhead (am·ial) spans of communications wires and cables shall be permitted to be attached to the exterior of a raceway-type mast intended for the attachment and support of such wires and cables.

805.154 Substitutions of Listed Communications Wires, Cables, and Raceways, and Listed Cable Routing Assemblies. The substitutions for commun ications cables listed in Table 805.1 54 and illusU"ated in Figure 805.1 54 shall be permitted. 805.156 Dwelling Unit Communications Outlet. For new consu·uction, a minimum of one communications outlet shall be installed within the dwelling in a readily accessible area and cabled to the service provider demarcation point.

Table 805.154 Cable Substitutions Cable Type CMR CMG, CM

CMX

Plenum

Permitted Substitutions CMP CMP, CMR CMP, CMR, CMG, CM

CMP

Riser

General purpose

Dwellings

E-.:ception No. 3: As permitted by 620.36.

(2) Other Applications. Commtmications wires and cables shall be separated at least 50 mm (2 in .) from conductors of any e lectric light, power, Class 1, non-power-limited fire alarm, or medium-power network-powe1·ed broadband communications circuits.

Type CM - Communications cables

IAJ

~

Cable A shall be permitted to be used in place of cable B.

FIGURE 805.154 70-678

Cable Substitution Hierarchy. NATIONAL ELECTRICAL CODE

2020 Edi tion

805.179

ARTICLE 805-COMMUNICATIONS CIRCUITS Part V. Listing Requirements 805.170 Equipment. Communications equipment shall be Listed as being suitable for elecu-ical connection to a communications network. Informational Note No. l: One way to determine applicable requirements is to refer to ANSI/ UL 60950-1-2014, Standard for Safety of Information TechnolOf!J' Equipnuml; ANSI/UL 1863-2012, Slandard for Safety Communications Circuit Accessories; or ANSI/ UL 62368-1-2014, Audio/Video, Information and Communication Technology Equipment - Part 1: Safety Requirenum.ls. Informational Note No. 2: Additional information regarding vo ltages, currents, and power allowed on communications circuits can be found in ANSl/ATIS 0600337-2016, Requirements for Maximum Voltage, Cumnt, and Power Lrmels U~ed in Commimicalions Transport Circuits.

shall not be marked on the cable or on the under-carpet communicati ons wire . Exceptivn: Voltage markings shall be permitted where the cable has multiple listing5 and vollage marking i5 required for one m· more of the listings. Informational Note: Voltage markings o n cables may be misinterpreted to suggest that t he cables may be suitable for C lass 1, e lectric ligh t, and power applications.

(A) General Requirements. The gen eral requirements in 805.1 79 shall apply. (B) Type CMUC Undercarpet Wires and Cables. Type CMUC

under-carpe t communications wires and cables shall be listed as being suitable for under-carpet use a nd sha ll also be listed as being resistant to flame spread.

(A) Primary Protectors. The primary protector shall consist of an arrester connected between each Line conductor and ground in an appropriate mounting. Primary protector terminals shall be marked to indicate line and ground as applicable.

Informational Note: One method of determ ining that cable is resistant to flame spread is by testing the cable to the VW-1 (vertical-wire) flame test in ANSI/ UL 1581-2017, Reference Standard for Electrical Wims, Cables and Hexible Cords.

Informational Note: One way to determine applicable 1·equirements for a listed primary protector is to refer to ANSI/ UL 497-2013, Standard for Proli!clorsfor Paired Conductor Conmwnications Circuits.

(C) Circuit Integrity (Cl) Cable or Electrical Circuit Protective System. Cables that are used fo r survivability of critical c ircuits under fire conditions shall be listed and meet either 805.179(C)(l) or805.1 79(C)(2) .

(B) Secondary Protectors. The secondary protector shall be Listed as suitable to provide means to safely limit currents to less than the current-carrying capacity of listed indoor communications wire and cable, Listed telephone set line cords, and listed communications terminal equipment having ports for external wire line communications c ircui ts. Any overvoltage protection, arresters, or grounding connection shall be connected on the equipment terminals side of the secondary protector currentlimiting means.

Informational Note: TI1e listing organization p rovides information for circuit integrity (Cl) cable and electrical circuit protective systems, inclucling installation requirements required to maintain the fire rating.

Informational Note: One way to determine applicable requirements for a listed secondary protector is to refer to ANSI/ UL 497A-2012, Standard for Secondary Pmli!clors for Communications Circuits.

(C) Plenum Grade Cable Ties. Cable ties intended for use in other space used for environmental air (plenums) shall be Listed as having low smoke and heat release properties. Informational Note: See NFPA 90A-2018, Standard/or the l nslallalion of Air-Conditioning and Ventilating Sys/J!ms, and ANSI/ UL 2043-2013, Standal"ll for Safel)• Ffre Test for Heal and Visible Smoke Release for D iscre/J! Products and Their Accessories Installed in Air-Handling SjJaces, for information on listing discrete products as having low smoke and heat release properties.

805.173 Drop Wire and Cable. Communications wires and cables without a m etallic shield, running from the last o utdoor support to the primary protector, shall be listed as being suitable for the purpose and sha ll have current-carrying capacity as specified in 805.90(A)(l)(b) or (A)( l )(c) . 805.179 Communications Wires and Cables. Communi cations ' "it-es and cables shall be listed in accordance with 805.179(A) through (F) and marked in accordance with Table 805.179 and 805.179(G) . Conductors in communications cabl es, other than in a coaxia l cable, shall be coppec Communications wires and cables shall have a voltage rating of not less than 300 volt5. The insulation for the individual conductors, other than the outer conductor of a coaxial cable, shall be rated for 300 volts minimum . The cable voltage rating

2020 Edition

NATIONAL ELECTRICAL CODE

(1) Circuit Integrity (Cl) Cables. Ci1-cuit integ1-ity (CI) cables speci fied in 805.l 79(A) through (D ), and used for survivability of critical circuits, shall have an additional classification using the suffix "CI." In orde1- to ma intain its listed fire rating, circuit integrity (Cl) cable shall only be installed in free air. Informational Note: One method of defining circuit integrity (Cl) cable is by establishing a minimu m 2-hour fire resistance rating for the cable when tested in accordance with ANSI/ UL 2196-2017, Standard for Fire Test for Circuit Integrity of FireResislant Power, lnslrunumtation, Control, mulDala Cah/es.

(2) Fire-Resistive Cables. Cables specified in 800. l 79(A) through (D ) and 805.1 79(C)(l ), that are part of an e lectrical circuit protective system, shall be fo-e-resistive cable identified with the protective system number on the product, or on the smallest unit container in which the product is packaged, and shall b e installed in accorda nce with the listing of the protective syste m. Informational Note No. I: One method of defining an electrical circuit protective system is by establishing a minimum 2-hour fire resistance rating for 1he system whe n tested in accordance

Table 805.179 Cable Markings Cable Marking CMP

CMR CMG CM CMX CMUC

Type Communications ple num cable Communications riser cable Communications general-purpose cable Communications general-purpose cable Communications cable, li mited use Under-carpet communications wire and cable

Informational Note: Cable types are list.ed in descending order of fire performance.

70-679

805.179

ARTICLE 810- RADIO AND TELEVISION EQUIPMENT

with U L Subjecr 1724, Outline of Investigation for Fire Tests for Elec-

trical Circuit Protective !:>)stems. Informational Note No. 2: The listing organization provides information for elecu-ical circuit protective systems (FHlT), including installation requirements for maintaining the fire rating.

(D) Types CMP-LP, CMR-LP, CMG-LP, and CM-LP Limited Power (LP) Cables. Types CMP-LP, CMR-LP, CMG-LP, and CMLP communications limited power cables shall be listed as suitable for carrying power and data up to a specified current limit for each conductor without exceeding the temperature rating of the cable where the cable is installed in cable bundles in free air or installed within a raceway, cable tray, or cable routing assembly. The cables shall be marked with the suffix "-LP(XXA)," where XX designates the current limit in amperes per conductor. Informational Note: An example of the marking on a communications cable with an LP rating is "Cl\llP-LP (0.6A) (7.5°C) 23 AWG 4 pair," which indicates that it is a 4-pair plenum cable with 23 AWG conductors, a temperature rating of 75°C, and a current limit of 0.6 ampere.

(E) Communications Wires. Communications wires, such as distributing frame wire and jumper wire, shall be listed as being resistant to the spread of fire. Informational Not.e: One method of defining resistant to the sjJ1·ead offire is that the cables do not spread fire to the top of the u-ay in the "UL Flame Exposure, Vertical Flame Tray Test" in ANSI/ UL 1685-2010, Standard for Safety for Vertical-Tray FirePropagation and Snwke-Rekase Test for Ekcllical and Optical-Fiber Cabws. The smoke mea5urements in the test method are not applicable. Another method of defining resistant to the spread of fire is for the damage (char length) not to exceed 1.5 m (4 ft 11 in.) when performing the CSA "Vertical Flame Test - Cables in Cable Trays," as described in CSA C22.2 No. 0.3-09, Test Methods for Ewct1ical Wires and Cabws. (F) H ybrid Power and Communications Cables. Listed hybrid

power and communications cables shall be permitted where the power cable is a Listed Type NM or NM-B, conforming to Pa.rt III of Article 334, and the communications cable is a listed Type CM, the jackets on the Listed NM oi- NM-B, and Listed CM cables are rated for 600 volt5 minimum, and the hybrid cable is listed as being resistant to the spread of fire. Informational Note: One method of defining nsistant to the sj1read offire is that the cables do not spread fire to the tOp of the u-ay in the "UL Flame Exposure, Vertical Flame Tray Test" in ANSI/UL 1685-2010, Standard for Safely for Vertical-Tray Fire-

Proj1ago.tion and Smok£-Release Test for Ewctrical and Optical-Fiber Cabws. The smoke measurements in the test method are not applicable. Another method of defining resistant to the sf1read offire is for the damage (char lengd1) not to exceed 1.5 m (4 ft 11 in.) when performing d1e CSA "Vertical Flame Test - Cables in Cable Trays," as described in CSA C22.2 No. 0.3-09, Test Methods for l.!,wctriccd Wires and Ca.bws.

(G) Optional Markings. Cables shall be permitted to be surface ma.1-ked to indicate special characteristics of the cable materials. Informational Note: These markings can include, but are not limited to, markings for limited.;;moke, halogen-free, low-smoke halogen-free, and sunlight resistance.

ARTICLE810 Radio and Television Equipment Part I. General 810.1 Scope. This article cove rs antenna systems for radio and television receiving equipment, amateur and citizen band radio transmitting and receiving equipment, and certain features of transmitter safety. This article covers an tennas such as wiresu·ung type, multi-element, vertical rod, flat, or parabolic and also covers the wiring and cabling that corrnect them to equipment. This article does not cover equipment and anten nas u sed for coupling carrier current to power line conductors.

810.2 Definitions. The definitions in Pa.rt I of Article 100 shall apply. 810.3 Other Articles. '.\Tiring from the source of power to and between devices corrnected to the interior wiring syste m shall comply with Chapters 1 through 4 other than as modified by Parts I and II of Article 640. Wiring for audio signal process ing, amplification, and reproduction equipment shall comply with Article 640. Coaxial cables that connect antennas to equipment shall comply with Article 820. 810.4 Community Television Antenna. The antenna shall comply with this article. The d istribution system shall comply with Article 820. 810.5 Radio Noise Suppressors. Radio inte rference eliminators, interference capacitors, or noise suppressors connected to power-supply leads shall be of a listed type. They shall not be exposed to physical damage . 810.6 Antenna Lead-In Protectors. Where an a ntenna lead-in surge protector is installed, it shall be listed as being suitable for limiting surges on the cable that connec t~ the antenna to the receiver/ transmitter e lectronics and shall be connected between the conductors and the grounded shield or other ground connection. The antenna lead-in protector shall be grounded using a bonding conductor or grounding e lecu·ode conductor installed in accordance with 810.21 (F) . Informational Note: For requirements covering protectors for antenna lead-in conductors, refer to UL 497£, Outline of Investi-

gation for Protectors for Anll!nna Lead-In Conductors.

810.7 Grom1ding Devices. '1\There bonding o r grounding is required, devices used to connect a sh ield, a sheath, noncurrent-;. (21)

1 (27)

1';. (35)

l '/z (41 )

2 (53)

2Y. (63)

3 (78)

3Y,. (91)

4 (103)

18 16 14 12 10

29 20 14 9 6

48 34 23 15 10

83 58 39 26 17

134 94 63 42 27

235 165 111 73 48

304 214 144 95 62

499 351 236 156 !02

751 527 355 235 153

1150 808 543 360 235

1497 1052 707 469 306

1952 1372 923 61 1 399

-

-

12 10

3

5 3

8

13 10

23 18

30 23

.;o

75 58

115 89

149 117

195 l.')2

-

-

l

6

39

5 6 (129) (155)

Notes: L T his cable is for concencric sm111ded conductors only. For compact stranded conduCLors, Table C. 7(A) should be used. 2. Two-hour fire-rated RHH cable has ceramifiable insulation, which has much larger diamecers chan ocher RHH wires. Consult manufacmrer's conduit fill tables. 'Types RHH, RH W, and RHW-2 wichouc outer covering.

2020 Edition

NATIONAL ELECTRICAL CODE

70-775

Annex C: Tables

INFORMATIVE ANNEX C

Table C.8(A) Maximum Number of Conductors or Fixture Wires in Liquidtight Flexible Metal Conduit (LFMC) (Based on Chapter 9: Table I, Table 4, and Table 5A)

T)'pe

Conductor Size (AWG/ kcmil)

Trade Size (Metric Designator) ~ (12)

Y,

Yi

l

(16)

(21)

(27)

l

Y..

(35)

l

Y,

(41)

2Y,

2 (53)

(63)

3 (78)

3Y, (91)

4 (103)

5 (129)

6 (155)

COMPACT CONDUCTORS

THW, THW-2, THHW

8 6 4 2 I 1/ 0 2/ 0 3/0 4/ 0

THHN, THWN, THWN-2

4 3 2

2 L l l l

l l

7 5 4 3 I

12 9 7 5 3

15 12 9 6 4

25 L9 14 LI 7

38 29 22 16 11

58 4.5 34 2.5 17

76 59 44 32 23

99 77 57 42 30

-

-

l l l l

3 2

4 3 3 2

6 .5 4 4

LO 8 7 6

L5 L3 11 9

20 16 14 12

26 21 18 15

-

-

l l l

l l l I l

3 2 2 I l

4 4 3 3 3

7 6 5 5 4

9 8 7 6 .5

12 10 9 8 7

-

-

0 0 0

l 1 1

I I I

I l l

1

1

1

l

l

I

3 3 3 2 I

4 4 3 3 3

6 5 5 4 4

-

-

13 8 6 4

17 11 7 6

28 L7 L2 9

43 26 19 14

66 41 29 22

86 53 38 28

112 69 50 37

-

-

5 4 3 3

8 6 5 4

12 10 8 7

19 15 L3 10

24 20 17 14

32 26 22 18

-

-

1

3 3 2 2

5 4 4 3 3

8 7 6 5 5

11 9 8 7 6

14 12 11 9 8

-

-

-

-

-

-

-

-

5 4 4 3 3

6 6 5 4 4

-

-

()

L

()

()

()

0 0

l l l l

0 0 0 0

()

0

I

1 I

250 300 350 400 500

()

0 0 0 0

()

()

()

0

L

600 700 750 900 1000

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

I

8 6 4 2 1

0 0 0

-

-

-

-

I I

2 L

I 0

l

l

1

1

0 0

l l

()

()

0

0

I I l l

250 300 350 400 500

0 0 0

0 0 0 0 0

1 0 0 0 0

600 700 750 900 1000

0 0 0 0 0

0 0 0

0 0 0 0 0

0 0 0 0 0

8 6 4 2

I

1/ 0 2/ 0 3/ 0 4/0

XHHW, XHHW-2

I I I I 0

I

()

0

L L I 0

()

0 3 2

4 3

I

5 4 3

1 1

l l

l I

7 4 3 2 I I

l l I

l

l

4 3 2

1

I

l l l l

1 L L L

0

l

l l l I

I

-

-

l l l I l

2 1 1

0

l l l l l

l l

4 3 3 2 2

9 6 4 3 2

15 11 8 6 4

20 15 11 7 6

33 24 L7 12 9

49 37 26 19 14

76 56 41 29 22

98 73 53 38 28

129 95 69 50 37

-

-

l

4 3 2 L

5 4 3 3

8 7 5 4

12 10 8 7

19 16 13 Ll

24 20 17 14

32 27 22 L8

-

-

l 1 1

l

8 7 6 6 .5

L5 12

l

5 5 4 4 3

II

1

3 3 3 2

-

-

L I I ()

1/ 0 2/ 0 3/ 0 4/0

0 0 0

0

()

()

l I I l

2.50 300 350 400 500

0 0 0 0 0

0 0 0 0 0

l

I

1

0 0 0 0

1 1 1 0

l l

1 1 l

1 L

9 8 7 6

11

10 8

(continues)

70-776

NATIONAL ELECTRICAL CODE

2020 Edi tion

Annex C: Tables

INFORMATIVE ANNEX C Table C.8(A)

Continued Trade Size (Metric Designator)

Conductor Size Type

(AWG /

%

Y,

~

kcmil)

(12)

(16)

(21)

I (27)

I Y. (35)

I Y2 (41)

2 (53)

2Y2 (63)

600 700 750 900 1000

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

I I 1

l l l I I

1 1 1 l l

0 0

3 (78)

3Y2 (91 )

4 ( 103)

2

4

5

I I I I

3 3

4 4 3 3

6 6 5

2 2

4 4

5 (129)

-

6 ( 155)

-

Definition: Compact stranding is the result of a manufacturing process where the stranded conductor is compressed to the extent that the interstices (voids between strand wires) are virtually eliminated.

2020 Edition

NATIONAL ELECTRICAL CODE

70-777

Annex C: Tables

INFO RMATIVE ANNEX C

Table C.9 Maximum Number of Conductors or Fixture Wires in Rigid Metal Conduit (RMC) (Based on Chapter 9: Table I , Table 4, and Table 5) Conductor Size

Type

(AWG/ kcmil)

Trade Size (M etric Designator)

'Ya ( 12)

Y, (16)

Yi

1

I Y,

(21)

(27)

(35)

IV, (41)

2 (53)

2Y, (63)

3

3 Y,

4

5

(78)

(91 )

(103)

( 129)

6 ( 155)

21 17 14 7 6

28 23 19

46 38 31 16 13

66 55 44 23 18

102 85 68 36 29

136 113 91 48 38

176 146 118 61 49

276 229 185 97 77

398 330 267 139 112

4 4 3

6 5 4 3

lO

14 12

22 19 17

7

11

30 26 23 15

38 34 29 19

60 53 46 30

87 76 66 44

6 5 4 4

10

13 11

17 14 12 11

26 23 20 17

38 33 28 24

3 2 2

4 4 4 3 3

5 4 4

8 7 6 6 5

13 11 10 9 8

18 16 15 13

1

l l l I

3 3 3 2 2

4 3 3 3 3

6 6 5 5 5

9 8 8 7 7

l l l

L l l

l l l

3

1

1

0

1 0

l l l

L

l

1

4 3 3 2 2

6 5 4 4 3

CONDUCTORS

14 12 10 8 6

-

4 3 3

4 3 2 1

-

l l l

l l l

0

1

1/0 2/0 3/0 4/0

-

0 0 0 0

l l

0 0

250 300 350 400 500

-

0 0 0 0 0

600 700 750 800 900

-

1000 1250 1500 1750 2000

-

TW, THHW, THW, THW-2

14 12 10 8

RHH*, RHW*, RHW-2*

RHH, RHW, RHW-2

Tv\l, THW, THHv\l, THW-2, RHH*, RHW*, RHW-2*

l l

7 6 5 2 l

12 10

8 4 3 2 2 l l

l

lO

8

9 7 5

11

l l l l

l l l l

2 2 l l

4 4 3 3

0 0 0 0 0

0

l l

0 0 0

1 1

l l l l

l l l l

l

1

1

0 0 0 0 0

0 0 0 0

0 0 0 0 0

0 0 0 0 0

l

1 0 0 0

1 1

0 0 0

0 0 0

l

0 0 0 0

0 0

0

0 0 0 0 0

0

0

0 0 0 0 0

-

9 7 5 3

15 12 9 5

25 19 14 8

44 33 25 14

59 45 34 19

98 75 56 31

140 107 80 44

215 165 123 68

288 221 164 91

370 284 212 118

581 446 332 185

839 644 480 267

14 12 10 8

-

6 5 3 1

10 8 6 4

17 13 10 6

29 23 18 11

39 32 25 15

65 52 41 24

93 75 58 35

143 115 90 54

191 154 120 72

246 198 154 92

387 311 242 145

558 448 350 209

6 4 3 2

-

1 1

3 1 l l l

8 6 5 4 3

11 8 7 6 4

18 14 12 7

27 20 17 14 10

41 31 26 22 15

5.5 41 35 30 21

71

l l l

5 3 3 2

53 45 38 27

111 83 71 60 42

160 120 103 87 61

1/ 0 2/ 0 3/0 4/ 0

-

0 0 0 0

l l l

2 2

3 3 2

6 5 4 3

8 7 6 5

13

18 15 13

0

l l l l

23 19 16 14

36 31 26 21

52 44 37 31

250 300 350 400 500

-

0 0 0 0 0

0 0 0 0 0

l l

l l l l l

3 2 l l l

4 3 3 3 2

6 5 5 4 3

8 7 6 6 5

11

0 0

l l l l l

9 8 7 6

17 15 13 12 10

25 22 19 17 14

600 700

-

0 0

0 0

0 0

l

l l

1 1

l l

3 2

4 3

.5

8

12

0

4

7

10

l

()

0

0

()

l

0

l l

l

l l l

()

10

l l

8 7 6

2

l l I I

11

9 8

10

8 6 .5

JO

11

(continues)

70-778

NATIONAL ELECTRICAL CODE

2020 Edi tion

Annex C: Tables

I NFORMATIVE ANNEX C Table C. 9

Continued Conduc tor Size (AWG/ kcmil)

Type

THHN, THWN, THWN-2

FEP, FEPB, PFA, PFAH, TFE

PFA, PFAH, TFE PFA, PFAH, TFE, Z

z

Trade Size (Me tric Designator)

% (12)

(16)

'Y. (21)

1 (27)

1Y.. (35)

Y,

l Y,

(41)

2 (53)

2Y,

(63)

4 (103)

5 (129)

3 (78)

3Y. (91 ) 3 3 3

4 4 3

7 6 6

IO 9 8

2

3 2 2

8 6

l l

5 4 3 3 3

6 (155)

750 800 900

-

0 0 0

0 0 0

0 0 0

0 0 0

l l l

l l l

l l l

2 2

IOOO 1250 1500 1750 2000

-

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

l l I

0 0

I l l l l

l l l l

1

l l l l

14 12 10 8 6

-

13 9 6 3 2

22 16 10 6 4

36 26 17 9 7

63 46 29 16 12

85 62 39 22 16

140 102 64 37 27

200 146 92 53 38

309 225 142 82 59

412 301 189 109 79

531 387 244 140 101

833 608 383 221 159

1202 877 552 318 230

4 3 2

l l

2

l

-

l l

l l

4 3 3 l

7 6 5 4

10 8 7 5

16 14 11 8

23 20 17 12

36 31 26 19

48 41 34 25

62 53 44 33

98 83 70 51

141 120 100 74

1/ 0 2/ 0 3/0 4/ 0

-

l 0 0 0

l l l l

1 1 1 l

3 2

4 3 3 2

7 6 5 4

10 8 7 6

16 13 9

21 18 15 12

27 23 19 16

43 36 30 25

63 52 43 36

250 300 350 400 500

-

0 0 0 0 0

0 0 0 0 0

1 1

l l

L

l 0

l l

3 3 2 2

5 4 3 3 2

7 6 5 5 4

10 8 7 7 5

13

l

l l l l l

10 8 7

20 17 15 13 11

29 25 22 20 16

600 700 750 800 900 IOOO

-

0 0 0 0 0 0

0 0 0 0 0 0

0 0 0 0 0 0

l l

l l l l l l

l l

0 0 0 0

l l l l l l

l l l l

3 3 3 2 2 l

4 4 4 3 3 3

6 5 5 4 4 4

9 8 7 7 6 6

13 11 ll LO 9 8

L4 12 10 8

-

12 9 6 3

22 16 ll

35 26 18

6

IO

61 44 32 18

83 60 43 25

L36 99 71 41

194 142 102 58

300 219 157 90

400 292 209 120

51.'> 376 269 154

808 590 423 242

ll66 851 610 350

6 4 3 2

-

2 l

l

7 5 4 3

13 9 7 6

17 12 IO 8

29 20 17 14

41 29 24 20

64

l

4 3 2

37 31

85 59 50 41

110 77 64 53

172 120 100 83

249 174 14.5 120

l

l

l I

l

l

11

44

11

.')

4 4

I

-

l

l

2

4

6

9

14

21

28

37

57

83

1/ 0 2/ 0 3/ 0 4/ 0

-

l

l l l

3 3 2

8 6

l

4

9 8 6

18 L4 12

1

5 4 3 2

ll

l 0 0

l l l l

LO

24 19 16 L3

30 2.'> 21 17

48 40 33 27

69 57 47 39

14 12 10 8 6

-

42 30 18

100

10 6 4 3

43 27 19

L64 116 71 45 31

234 166 102 64 45

361 256 157 99 69

482 342 209 132 93

621 440 269 170 120

974 691 423 267 188

1405 997 610 386 271

4 3 2

-

13 9 8 6

22 16 13 IO

31 22

48 35 29 23

64 47 39 31

82 60 50 40

129 94 78 63

186 136 Ll3 92

l

1.5

l l

l l

26 LS 7 5

11

8

73 52 32 20 14

3 2 l l

5 4 3 2

9 7 6 5

LI

71

.5

19

L5

(continues)

2020 Edition

NATI ONAL ELECTRICAL CODE

70-779

Annex C: Tables Table C. 9

INFORMATIVE ANNEX C

Continued Trade Size (Metric Designator)

Conductor Size Type

XHHW, ZW. XHHW-2,XHH

XHHW, XHHW-2, XHH

(AWG/ kcmil)

% (12)

Y, (16)

% (21)

1 (27)

l Y. (35)

1Y2 (41)

2 (53)

2Y2 (63)

3 (78)

3Y, (91 )

4 (103)

5 (129)

6 (155)

15 12 9 5 3

25 19

44 33 25 14

59 45 34 19 14

98 75 56 31 23

140 107 80 44 33

215 165 123 68 51

288 221 164 91 68

370 284 212 118 87

581 446 332 185 137

839 644 480 267 197

2

7 6 5

10

8 7

16 14 12

24 20 17

37 31 26

49 41

1

4 3 3

%

63 53 45

99 84 70

143 121 101

14 12 10 8 6

-

9 7 5 3

4 3 2

-

l l I

l

-

I

I

l

4

5

9

12

19

26

33

52

76

-

l

0 0 0

I I

3 2

4 3 3 2

7 6 5 4

10 9 7 6

16 13

l l

l l l l

22 18 15 12

28 23 19 16

44 37 30 25

64 53 44 36

250 300 350 400 500

-

0 0 0 0 0

0 0 0 0 0

3 3 2 2

7 6 6 5 4

IO

l

5 4 3 3 2

9 7 7 5

13 11 10 9 7

20 18 15 14 11

30 25 22 20 16

600 700 750 800 900

-

0 0 0 0 0

0 0 0 0 0

1 1

I I

1 1 1

4 4 4 3 3

6 5 5 4 4

9 8 7 7 6

13

l

3 3 3 2 2

10 9

1000 1250 1500 1750 2000

-

()

0 0 0 0 0

1 1

3 2 1 I I

4 3 2 1 1

6 4 4 3 3

8 6 5 5 4

1/ 0 2/ 0 3/0 4/ 0

I

()

0 0 0

I

14

8 6

10

I I

l

I

l

1 1 l

l l I

0

1

1 1 1 1

0 0 0 0 0

1 1 0 0 0

1 1 1 1 1

()

0 0 0 0 0

1 0 0 0 0

0 0

()

0 0 0

1 1 l l l

1 1 1 1 l

11

9

l l l

11 ll

FIXTURE WIRES

RFH-2, FFH-2, RFHH-2

18 16

-

8 7

15 12

24 20

42 35

57 48

94 79

134 113

207 174

276 232

355 299

557 470

804 678

SF-2, SFF-2

18 16 14

-

11 9 7

19 15 12

31 25 20

53 44 35

72 59 48

118 98 79

169 140 113

261 215 174

348 288 232

448 370 299

703 581 470

1014 839 678

SF-I, SFF-1

18

-

19

33

54

94

127

209

299

461

616

792

1244

1794

18 16

-

14 11

25 20

40 32

69 56

94 76

155 125

221 178

341 275

455 367

585 472

918 741

1325 1070

RFH-1, TF, TFF, XF, XFF

14

-

9

15

25

44

59

98

140

215

288

370

581

839

TFN, TFFN

18 16

-

2~~

17

40 30

64 49

111 84

1.50 115

248 189

354 270

54.5 416

728 556

937 715

1470 1123

2120 1620

PF, PFF, PGF, PGFF, PAF, PTF, PTFF, PAFF

18 16 14

-

21 16 12

38 29 22

61 47 35

10.'i 81 61

143 110 83

235 181 136

33.5 259 194

517 400 300

690 534 400

888 687 515

1394 1078 808

2011 1555 1166

ZF, ZFF, ZHF

18 16 14

-

28 20 l.5

49 36 26

79 58 42

135 100 73

184 136 100

303 223 164

432 319 234

666 491 361

889 656 482

11 45 844 621

1796 1325 974

2592 19 12 1405

18 16 14 12 10

-

42 29 19 13 9

73 51 34 24 15

118 82 55 38 2.5

203 142 95 66 44

276 192 129 90 59

454 317 213 148 98

648 452 304 211 140

1000 697 468 326 21.5

1334 931 625 435 288

1717 1198 805 560 370

2695 1880 1263 878 .581

3887 2712 1822 1267 839

XF, XFF

KF-2, KFF-2

(continues)

70-780

NATIONAL ELECTRICAL CODE

2020 Edi tion

Annex C: Tables

I NFORMATIVE ANNEX C Table C. 9

Continued Conduc tor Size

Type

KF-1, .KFF-1

(AWG/ kcmil)

18 16 14 12 10

XF,XFF

12 JO

Trade Size (M e tric Designator)

% (12)

Y,

(16)

-

48 34 23

-

.5

1.5

IO

3

'Y. (21)

1 (27)

1Y.. (35)

84 59 40 26 17

136 96 64 42 28

234 165

8 6

13 JO

(41)

2 (53)

(63)

3 (78)

3Y. (91 )

4 (103)

5 (129)

6 (155)

73 48

318 224 150 100 65

524 368 248 164 107

748 526 354 234 153

1153 810 545 361 236

1540 I082 728 482 315

1982 1392 937 62 1 405

3109 2185 1470 974 636

4486 3152 2120 1405 918

23 18

32 25

52 41

75 58

115 90

154 120

198 154

311 242

448 350

lll

l Y,

2Y,

Notes: 1. This table is for concentric su-anded conductors only. For compact stranded conductors, Table C.8(A) should be tL~ed. 2. Two-hour fire-rated RHH cable has ceramitiable insulation, wh ich has much larger d iameters than other Rl-lH wires. Consu lt manufacturer's conduit fill tables. *Types RHH, RHW, and Rl-fW-2 without outer covering.

2020 Edition

NATIONAL ELECTRICAL CODE

70-781

Annex C: Tables

INFO RMATIVE ANNEX C

Table C.9(A) Maximum Number of Conductors or Fixture Wires in Rigid Metal Conduit (RMC) (Based on Chapter 9: Table I, Table 4, and Table 5A)

Type

Conductor Size (AWG/ kcmil)

Trade Size (M etric Designator)

'Ya ( 12)

Y, (16)

Yi

1

I Y,

(21)

(27)

(35)

IV, (41)

2 (53)

2Y, (63)

11

38 29 22 16

3

3 Y,

4

5

6

(78)

(91 )

(103)

(129)

(155)

59 45 34 25 17

78 60 45 33 23

101 78 58 43 30

158 122 91 67 47

228 176 132 97 68

20 17 14 12

26 22 19 15

41 34 29 24

59 50 42 35 28 24 22 20 17 13 12 11 10 9

COMPACT CONDUCTORS

THW, THW-2, THHW

THHN, THWN, THWN-2

XHHW, XHH W-2

8 6 4 2 l

-

2 l 1 l l

4 3 2 1 1

7 5 4 3 1

12 9 7 5 3

16 12 9 7 5

26 20 15 8

11

l

1 1 L

1 1 1 1

3 2 l 1

4 3 3 2

7 6 5 4

lO

l.')

8

13

7 6

11

l

l l l l l

l l l

3 3 2

7 6 5

1 l

l 1

4 4 3 3 3

l 1

l l l

l l l

I

1

3 3 3 2

1/ 0 2/ 0 3/0 4/ 0

-

250 300 350 400 500

-

0 0 0 0 0

0 0 0 0 0

600 700 750 900 LOOO

-

0 0 0

0 0 0 0 0

8 6 4 2 l

-

()

0 0

()

0 -

2 l l

l 1 1

I

5 3 I I

1 1 L 0 0 0 0

0

()

()

()

0

1 l

-

-

-

-

8 5 3 2

13 8 6 4

18 11 8 6

30 18 13

43 26 19 14

1 1 1 1

4 3 2 l

5 4 3 3

8 7 6 5

12 10

1 l l 1 0

1 1 1 l 1

2 l l l 1

4 3 3 2 1

5 4 4 3

0 0 0 0 0

l l l 0

l 1 1 1 1

15 11 8 6 4

1 1 I I

l

9

5

4

l

2.5 21 17 14 11

'.~

8 7 6 5 5

l 1 1 l l

2 1 1 1 1

21 L5 LI 8 6

34 25 18 13 LO

51 42 35 29

73 60 51 42

8 7 6

14 L2 Ll LO 8

23 20 L7 L5 13

33 28 25 22 19

4 3 3 2 2

5 4 4 3 3

6 6 5 4 4

LO 9 9 7 6

1.5 13 13 LO 9

49 36 26 19 14

76 56 41 29 22

LOl 75 55 39 29

130 97 70 50 38

205 152 110 79 59

296 220 159 114 86

25 21 17 14

32 27 22 19

51 43 35 29

73 62 51 42

11 10 9 8 6

15 L3 Ll 10 8

23 20 18 16 L3

34 29 25 23 L9

()

0

600 700 750 900 LOOO

-

0 0 0 0 0

8 6 4 2 l

-

3 2 l 1 l

.5

I I

9 6 5 3 2

1/ 0 2/ 0 3/0 4/ 0

-

l

1 L L l

4 3 2 l

5 4 3 3

8 7 6 5

12

0 0

I I I I

8 7

19 16 13 11

250 300 350 400 500

-

0 0 0 0 0

I

L

0 0 0 0

I I

1 1 1 1 l

2 l l 1 l

4 3 3 2

5 5 4 4 3

8 7 6 6 5

l

4 3

1 0

l

-

32 26 22 18

()

()

179 79 59

I

0 0

9 8 7 7 6

19 15 13 LO

10

0 0

()

6 5 5 4 4

258 159 1 L4 86

0 0 0

0

4 4 4 3 3 -

()

()

9 8 7

Ll4 70 50 38

-

L

7 7 5

19 17 15 13 Ll

88 5.5 39 29

250 300 350 400 500

()

11

-

-

()

12

66 41 29 22

1/ 0 2/ 0 3/0 4/ 0

I I I

9 8

8

7

10

]()

Jl ()

(continues)

70-782

NATIONAL ELECTRICAL CODE

2020 Edi tion

Annex C: Tables

INFORMATIVE ANNEX C Table C.9(A)

Continued Conduc tor Size

Type

(AWG / kcmil)

Trade Size (Metric Designator)

%

Y,

'Y.

(12)

(16)

(21)

1 (27)

1Y.. (35)

l Y, (41)

2 (53)

I I l 600 0 0 0 l 1 l 700 0 0 0 750 0 0 0 1 1 1 900 0 0 0 I I 0 1000 0 0 0 I I 0 Defini tion: Compact stmnding is the result ofa manufactu ring process where the strnnded conductor is compressed to the extent that the interstices (voids between su-and wires) are virtually e liminated.

2020 Edition

NATIONAL ELECTRICAL CODE

2Y, (63) 2 I I I I

3 (78)

3Y. (91 )

4 (103)

5 ( 129)

6 ( 155)

4 3 3 2 2

5 4 4 3 3

7 6 5 5 4

10 9

15 13 12 11 10

8 7 7

70-783

Annex C: Tables

INFO RMATIVE ANNEX C

Table C.10 Maximum Number of Conductors or Fixture Wires in Rigid PVC Conduit, Schedule 80 (Based on Chapter 9: Table I , Table 4, and Table 5) Conductor Size

Type

Trade Size (M etric Designator)

(AWG/

'Ya

Y,

Yi

1

I Y,

IV,

2

2Y,

3

3 Y,

4

5

6

kcmil)

( 12)

( 16)

(21)

(27)

(35)

(41)

(53)

(63)

(78)

(91 )

(103)

(129)

(155)

39 32 26 13

56 46 37 19 16

88 73 59 31 24

118 98 79 41 33

153 127 103 54 43

243 202 163 85 68

349 290 234 122 98

26 23 20 13

33 29 25 17

53 47 41 27

77 67 58 38

11

15 13 9

23 20 17 15

33 29 2.5 21

11

CONDUCTORS

RHH, RHW, RHW-2

TW, THHW, THW, THW-2

RHH*, RHW*, RHW-2*

14 12 10 8 6

-

4 3 2 1

-

1/0 2/0 3/0 4/0

5 4 3

l

l l

I

9 7 6 3 2

17 14 6 4

23 19 15 8 6 5 4 4 2

8 7 6 4

12 9 6

19 17 14 9

5 4 4 3

8 7 6 5

10 8 7

2 2

4 3 3 3 2

5 .5 4 4 3

7 6 5 5 4

10 9 8 7

16 14 13 12 10

I

3 2 2 2

3 3 3 3 2

6 5 5 4 4

8 7 7 7 6

2

4 3 2 2 l

5 4 4 3 3

11

11

()

I I

0 0

l

l l l

1

1

3 3 3 1

-

0 0 0 0

0 0 0 0

l l l

l l l

l l l

0

I

I

3 3 3 2

250 300 350 400 500

-

0 0 0 0 0

0 0 0 0 0

0

1

l

1

0

l

l

0 0 0

1 0 0

I I I

I I

1

1

600 700 750 800 900

-

0 0 0 0 0

0 0 0 0 0

()

0 0 0 0 0

0 0 0 0 0

LOOO

1250 1500 1750 2000

-

0 0 0

0 0 0 0 0

0 0 0

0 0 0 0 0

0 0 0 0 0

14 12 10 8

-

6 4 3 l

9 6 3

6

35 27 20 11

14 12

-

4 3 2 1

8 6 5 3

13 10 8 5

-

1 1

1 1

l l

0

l l l

3 3 2

1/ 0 2/ 0 3/0 4/ 0

-

0 0 0 0

0 0

250 300 350 400 500

-

0 0 0 0 0

600 700

-

0 0

IO

8 TW, THW, THHW, THW-2, RHH*, RHW*, RHW-2*

3 2 1

6 4 3 2 l

l

()

0

0 0 0 0

1

1

11

l l l

I I I I

l l l

1

l l l l

l

l

l

0 0

I I

()

0

0 0

I I 1

49 38 28 15

82 63 47 26

23 19 15 9

32 26 20 12

l l

7 5 4 3 2

l l l l

l l l l

0 0 0 0 0

0 0

1 1

0

0 0

0 0

0 0

11

l l

()

0 19 15 11

l

11

l

l l l l l

118 91 68 37

185 142 106 59

250 192 143 79

324 248 185 103

514 394 294 163

736 565 421 234

.55 44 34 20

79 63 49 29

123 99 77 46

166 133 104 62

215 173 135 81

341 274 214 128

490 394 307 184

9 7 6 5 3

16 12 8 6

22 17 14 12 8

35 26 22 19 13

48 3.5 30 26 18

62 46 39 33 23

98 73 63 53 37

141 105 90 77 54

3 2

5 4 3 3

7 6 5 4

11 10

8 7

15 13 11 9

20 17 14 12

32 27 23 19

46 39 33 27

2

3 3

l l l

l l l l l

l

5 5 4 4 3

7 6 6 5 4

9 8 7 7 5

15 13 12 10 9

22 19 17 15 13

0 0

l l

1 1

l l

2 2

3 3

4 4

7 6

10

l l

lO

l l l l

2

2

l l l l

9 (continues)

70-784

NATIONAL ELECTRICAL CODE

2020 Edi tion

Annex C: Tables

I NFORMATIVE ANNEX C Table C.10

Continued Conduc tor Size (AWG/ kcmil)

Type

THHN, THWN, THWN-2

FEP, FEPB, PFA, PFAH, TFE

PFA, PFAH, TFE PFA, PFAH, TFE, Z

z

Trade Size (Me tric Designator)

% (12)

(16)

'Y. (21)

1 (27)

1Y.. (35)

(41)

Y,

l Y,

4 (103)

5 (129)

(63)

3 (78)

3Y. (91 )

1 1 1

1 1 1

3 3 2

4 3 3

6 6 5

8 8 7

l

I

2

3 2

5 4 3 3 2

7 5 4 4 3

2 (53)

2Y,

6 (155)

750 800 900

-

0 0 0

0 0 0

0 0 0

0 0 0

0 0 0

1000 1250 1500 1750 2000

-

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

I

1

0 0 0

l l

l l l l

0

1

l l l l

14 12 10 8 6

-

9 6 4 2 I

17 12 7 4 3

28 20 13 7 5

51 37 23 13 9

70 51 32 18 13

118 86 54 31 22

170 124 78 45 32

265 193 122 70 51

358 261 164 9.5 68

464 338 213 123 89

736 537 338 195 141

1055 770 485 279 202

4 3 2

1

1

I

6 5 4 3

8 7 6 4

14 12 10 7

20 17 14

0

l I I

3 3 2

l

-

31 26 22 16

42 3.5 30 22

54 46 39 29

86 73 61 45

124 105 88 65

1/ 0 2/ 0 3/0 4/ 0

-

0 0 0 0

l l l

1 1 1

2

0

I

6 5 4 3

9 7 6 5

14

l l l

3 3 2 1

9 8

18 15 13 10

24 20 17 14

38 32 26 22

55 46 38 31

250 300 350 400 500

-

0 0 0 0 0

0 0 0 0 0

1 0 0 0 0

l l l l l

1 1

3 2

I

I

I I

6 5 5 4 3

8 7 6 6 5

11

1 1

4 3 3 3 2

18 15 13 12 IO

25 22 19 17 14

600 700 750 800 900 1000

-

0 0 0 0 0 0

0 0 0 0 0 0

0 0 0 0 0 0

0 0 0 0 0 0

1 1 1 1 0 0

I I I

3 2 2 2 1

l

I I l l l l

I

4 3 3 3 3 2

5 4 4 4 3 3

8 7 7 6 6 5

12 10 9 9 8 7

14 12 10 8

-

8 6 4 2

16 12 8 5

27 20 14 8

49 36 26 15

68 50 36 20

115 84 60 34

164 120 86 49

257 188 135 77

347 253 182 104

450 328 235 135

714 521 374 214

1024 747 536 307

6 4 3 2

-

I I I

3 2

6 4 3 3

10 7 6 5

14 10 8 7

24 17 14 12

35 24 20 17

55 38 32 26

74 52 43 35

96 67 56 46

152 106 89 73

218 153 127 105

I

1

l l

I

I I

1

1 1

10

11

l l l

9 8 7 6

l

-

I

l

l

3

5

8

11

18

25

32

51

73

1/ 0 2/ 0 3/ 0 4/ 0

-

0 0 0 0

1

3 2

4 3 2

7

10

l l

l l l

.5

20 17 14

27 22 18

0

1

15 12 10 8

ll

l !)

42 35 29 24

61 50 41 34

14 12 10 8 6

-

IO

19 14 8 5 4

33 23 14 9 6

59 42 26 16

1233 875 536 339 238

4 3 2

-

I I I I

2

4 3 2

8 5 5 4

l

7 4 3 I

I l l

I

l l

ll

l

4 4

8 6 .5

82 58 36 22 16

138 98 60 38 26

198 141 86 54 38

310 220 135 85 60

418 297 182 115 81

542 385 235 149 104

860 610 374 236

11

18 13 11 9

26 19 16 13

41 30 25 20

55 40 33 27

72 52 43 35

114 83 69 56

8 6 5

166

164 119 99

80 (continues)

2020 Edition

NATI ONAL ELECTRICAL CODE

70-785

Annex C: Tables Table C. 10

INFO RMATIVE ANNEX C

Continued Trade Size (Me tric Designator)

Conductor Size Type

XHHW,ZW, XHHW-2,XHH

XHHW, XHHW-2, XHH

(AWG/ kcrnil)

% (12)

Y,

(16)

% (21)

1 (27)

l Y. (35)

1Y2 (41)

2 (53)

2Y2 (63)

3 (78)

3Y, (91)

4 (103)

5 (129)

6 (155)

19 15

35 27 20 Ll 8

49 38 28 15

82 63 47 26 19

Ll8 91 68 37 28

185 142 106 .59 43

250 192 143 79 59

324 248 185 103 76

5L4 394 294 163 121

736 565 421 234 173

6

8 7 6

14 12 10

20 17 14

31 26 22

42 36 30

55 47 39

87 74 62

125 106 89

14 12 l0 8 6

-

6 4 3 l l

11

6 3 2

11

4 3 2

-

l l L

l l l

3 3 2

l

-

0

l

l

3

4

7

10

16

22

29

46

66

-

0 0 0 0

l l l 0

l l

2 l L L

3 3 2

6 5 4 3

9 7 6 5

14 ll 9 8

19 16 L3 11

24 20 17 14

39 32 27 22

56 46 38 32

250 300 350 400 500

-

0 0 0 0 0

0 0 0 0 0

l 1 0 0 0

3 2 1 L l

4 3 3 3 2

6 5 5 4 3

9 7 6 6 5

11

10 8 7 6

18 15 14 L2

26 22 20 17 14

600 700 750 800 900

-

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

L L 1 l l

3 2 2

4 3 3 3 3

5 4 4 4 3

8 7 6 6 5

11

1 0

L L l 1 1

1000 1250 L500 1750 2000

-

()

0 0 0 0 0

()

0 0 0 0 0

0 0 0 0 0

l l

1 1

1 1

0 0 0

I l l

3 2 1

1 1

2 L L L L

1 1

.5 4 3 3 2

7 6 5 4 4

1/ 0 2/ 0 3/0 4/ 0

()

0 0 0

9

6 4

I

l

()

0 0 0

.')

4

11

l

L

I

I I

1 1 1 1

L L

1 1 I

l

1

l

JO

JO

9 9 8

FIXTURE WIRES

RFH-2, FFH-2, RFHH-2 SF-2, SFF-2

SF-I, SFF-1 RFH-1, TF, TFF, XF, XFF

18 16

-

6 5

11

18 16 14

-

7 6 5

14

18

-

18 16

-

19 16

34 28

47 39

79 67

Ll3 95

177 150

239 202

310 262

492 41.5

706 595

9

24 19 16

43 35 28

59 49 39

100 82 67

L43 Ll8 95

224 185 150

302 250 202

391 324 262

621 514 41.5

890 736 595

L3

25

42

76

105

177

253

396

534

692

1098

L575

JO

18 15

31 25

56 4.5

77 62

130 105

L87 L51

293 236

395 3L9

511 413

81 L 655

ll 63 939

8

9 11

14

-

6

11

19

35

49

82

Ll8

185

250

324

514

736

TFN, TFFN

18 16

-

15 12

29 22

50 38

90 68

124 95

209 159

299 229

468 3.58

632 482

818 625

1298 992

1861 1422

PF, PFF, PGF, PGFF, PAF, PTF, PTFF, PAFF

18 16 14

-

1.5 LL 8

28 22 16

47 36 27

8.'i 66 49

118 91 68

198 153 115

284 219 L64

444 343 257

599 463 347

776 600 450

1231 952 714

1765 L365 L024

ZF, ZFF, ZHF

18 16 14

-

19 14

36 27 19

61 45 33

110 81 59

1.52 112 82

255 188 138

366 270 L98

572 422 310

772 569 4L8

LOOO

738 542

1.587 11 71 860

2275 1678 1233

18 16 14 12 10

-

29 20 13 9 6

54 38 25 17

91 64 43 30 L9

L65 115 77 53 35

228 159 107 74 49

383 267 179 12.5 82

549 383 257 179 Ll8

859 599 402 280 185

1158 808 543 377 250

L50l !047 703 489 324

2380 1661 11 16 776 .5 L4

3413 2381 1600 11 13 736

XF,XFF

KF-2, KFF-2

LO

ll

(continues)

70-786

NATIONAL ELECTRICAL CODE

2020 Edi tion

Annex C: Tables

I NFORMATIVE ANNEX C Table C.10

Continued Conduc tor Size

Type

KF-1, .KFF-1

(AWG/ kcmil)

18 16 14 12 10

XF,XFF

12 IO

Trade Size (M e tric Designator)

% (12)

Y,

(16)

'Y. (21)

1 (27)

1Y.. (35)

106 74 50 33 21

190 133 90 59 39

263 185 124 82

10 8

19 15

-

33 23 15 7

63 44 29 19 13

-

3 2

6 5

10

2 (53)

(63)

3 (78)

3Y. (91 )

4 (103)

5 (129)

6 (155)

.'>4

442 310 209 138 90

633 445 299 198 129

991 696 468 310 203

1336 939 632 418 273

1732 1217 818 542 3.'>4

2747 1930 1298 860 562

3938 2767 1861 1233 806

26 20

44 34

63 49

99 77

133 104

173 135

274 214

394 307

l Y,

(41)

2Y,

Notes: 1. This table is for concentric su-anded conductors only. For compact stranded conductors, Table C.9(A) should be tL~ed. 2. Two-hour fire-rated RHH cable has ceramitiable insulation, wh ich has much larger d iameters than other Rl-lH wires. Consu lt manufacturer's conduit fill tables. *Types RHH, RHW, and RI-fW-2 without outer covering.

2020 Edition

NATIONAL ELECTRICAL CODE

70-787

Annex C: Tables

INFO RMATIVE ANNEX C

Table C.IO(A) Maximum Number of Conductors or Fixture Wires in Rigid PVC Conduit, Schedule 80 (Based on Chapter 9: Table I, Table 4, and Table 5A) Conductor Size

Type

Trade Size (M etric Designator)

(AWG/

'Ya

Y,

Yi

1

I Y,

IV,

2

2Y,

3

3 Y,

4

5

kcmil)

( 12)

( 16)

(21)

(27)

(35)

(41)

(53)

(63)

(78)

(91 )

(103)

(129)

6 ( 155)

COMPACT CONDUCTORS

THW, THW-2, T H HW

TH HN, THWN, THWN-2

XHHW, XHH W-2

1 1 1 1 0

3 2

l

-

1/ 0 2/ 0 3/0 4/ 0

-

()

250 300 350 400 500

1 1

5 4 3 1 1

9 7 5 4 3

13 lO 7 5 4

22 17 13 9 6

32 2.5 18 13 9

50 39 29 21 15

68 52 39 29 20

88 68 51 37 26

140 108 81 60 42

200 155 116 85 60

1 1 1 1

2

0 0

1 1 0 0

3 3 2 1

6 5 4 3

8 7 6 5

13 11 9 8

17 15 12 10

23 19 16 13

36 30 26 22

52 44 37 31

-

0 0 0 0 0

0 0 0 0 0

1 0 0 0 0

1 1 1 1

2 2 1

4 3 3 3 2

6 5 5 4 3

8 7 6 6 5

11

l

1 1 1 1 1

9 8 7 6

17 15 13 12 10

25 21 19 17 14

600 700 750 900 1000

-

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

1 1 1 0 0

1 1 1 1 1

I

3 2 2 1

4 3 3 3 2

5 4 4 4 3

8 7 7 6 5

12 10 10 8 8

8 6 4 2 1

-

8 6 4 2

()

I

-

-

l

1

1 1 I I

l

-

-

-

-

-

-

11 6 5 3

15 9 6 5

25 15 8

36 22 16 12

57 35 25 19

77 47 34 25

99 61 44 33

158 98 70 53

226 140 100 75

3 2 1 1

4 3 3 2

7 6 5 4

10 8 7 6

16 13 11 9

22 18 15 12

28 23 19 16

45 37 31 25

64 53 44 37

1 1 1

1 1 1

l

l

1

1

3 3 2 1 1

4 4 3 3 2

7 6 5 5 4

10 8 7 6 5

12 11 9 8 7

20 17 15 13 11

29 25 22 19 16

l

1 1 1 1 0

1 1 1 1 1

I

0 0 0 0

1 1 1 1

3 3 3 1 1

4 4 4 3 3

6 5 5 4 3

9 8 8 6 5

13 12 11 9 8

12 9 6 5 3

17 13 9 6 5

29 21 15 11 8

42 31 22 16 12

65 48 35 25 19

88 65 47 34 25

114 85 61 44 33

18 1 134 98 70 53

260 193 140 100 75

3 2 1 1

4 3 3 2

7 6 5 4

IO

8 7 6

16 13 11 9

22 18 15 12

28 24 19 16

45 38 31 26

64 54 44 37

1 1 1 1

1 1 1 1

l

l

3 3 2 1 1

5 4 3 3 2

7 6 5 5 4

10 8 7 7 5

13 11 lO 9 7

21 17 15 14 11

30 25 22 20 17

3 I I I

6 3 2 1

0 0 ()

I I I

1 1 1

0

0

I

1/ 0 2/ 0 3/0 4/ 0

-

250 300 350 400 500

-

0 0 0 0 0

0 0 0 0 0

1 1 0 0 0

600 700 750 900 1000

-

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

8 6 4 2

-

1 1 1 1 1

4 3

7 5 3 2

1/ 0 2/ 0 3/0 4/ 0

-

0 0 0 0

I I I

1

0

1

250 300 350 400 500

-

0 0 0 0 0

0 0 0 0 0

I I I

I

1 1

-

1 1 1 1

I I I

l

I I I

0 0

11

-

-

-

(continues)

70-788

NATIONAL ELECTRICAL CODE

2020 Edi tion

Annex C: Tables

I NFORMATIVE ANNEX C Table C.IO(A)

Continued Conduc tor Size

Type

(AWG/ kcmil)

Trade Size (M e tric Designator)

%

Y,

'Y.

(12)

(16)

(21)

-

1 (27)

1Y.. (35)

l Y, (41)

2 (53)

I I l 0 1 l 0 0 0 0 1 1 0 0 I I 0 0 0 0 I 0 Definition: Compact stmndingis the result ofa manufacturing process where the strnnded conductor is compressed to the extent that the interstices (voids between su-and wires) are virtually e liminated.

600 700 750 900 1000

2020 Edition

NATIONAL ELECTRICAL CODE

0 0 0

0 0 0 0 0

2Y, (63)

3 (78)

3Y. (91 )

4 (103)

I I I I I

3 3 2 2 I

4 4 3

6 5 5 4

3

3

3

5 ( 129)

6 ( 155)

9

13 12

8 7 6 6

11 9 8

70-789

Annex C: Tables

INFO RMATIVE ANNEX C

Table C.11 Maximum Number of Conductors or Fixture Wires in Rigid PVC Conduit, Schedule 40 and HDPE Conduit (Based on Chapter 9: Table 1, Table 4, and Table 5) Conductor Size

Type

Trade Size (M etric Designator)

(AWG/

'Ya

Y,

Yi

1

I Y,

IV,

2

2Y,

3

3 Y,

4

5

6

kcmil)

( 12)

( 16)

(21)

(27)

(35)

(41)

(53)

(63)

(78)

(91 )

(103)

(129)

(155)

20 16 13 7 5

27 22 18 9 7

45 37 '.{0 15 12

64 53 43 22 18

99 82 66 35 28

L33 LlO 89 46 37

171 142 115 60 48

269 224 181 94 76

390 323 261 137 109

4 4 3 1

6 5 4 3

lO

8 7 5

14 12 10 7

22 19 16 11

29 25 22 14

37 33 28 19

59 52 45 29

8.5 75 65 43

4 3 3 2

6 5 4 4

9 8 7 6

13 11 9 8

16 14 12 LO

26 22 19 16

37 32 28 24

3 2 2 1 l

4

6

4 3 3 3

.5

5 4 4

8 7 6 6 5

12 11 10 9 8

18 16 14 13

3 3 2 2 2

4 3 3 3 3

6 6 5 5 5

9 8 8 7 7 6 5 4 3 3

CONDUCTORS

RHH, RHW, RHW-2

TW, THHW, THW, THW-2

RHH*, RHW*, RHW-2*

TW, THW, THHW, THW-2, RHH*, RHW*, RHW-2*

14 12 10 8 6

-

4 3 2 1

11

l

7 5 4 2 l

4 3 2 1

-

l l

l l

2

l

0

1 1

1 1

1/0 2/0 3/0 4/0

-

0 0 0 0

l 0 0 0

1 1 1

l

l l

2 1 1

I

l

I

250 300 350 400 500

-

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

1

1

l

l

1 1 0

1 1 1

1 1 1 1 1

600 700 750 800 900

-

0 0 0 0 0

0 0 0 0

0 0 0 0 0

0 0 0 0 0

l 0 0 0 0

1 1 l l 1

1 1 L L 1

2 1

LOOO

-

0 0 0

0 0 0 0 0

0 0 0

0 0 0 0 0

l I I

l I I

l

3

0 0

l l

I I

0

1 0

1

0

0 0 0 0 0

l

1250 1500 1750 2000

l

1 l

1 1

4 3 3 2 2

14 12 10 8

-

8 6 4 2

14

24 18 13 7

42 32 24 13

57 44 32 LS

94 72 54 30

135 L03 77 43

209 160 119 66

280 215 L60 89

361 277 206 115

568 436 325 181

822 631 470 261

14 12 10 8

-

5 4 3 1

9 8 6

16 13 10 6

28 22 17

38 30 24 14

63 50 39 23

90 72 56 33

139 112 87 52

186 L50 117 70

240 193 150 90

378 304 237 142

546 439 343 205

6 4 3 2 l

-

1 1

2 1

18 13

l

1 1

7

26 19 16 14 10

40 30 25 22 15

53 40 34 29 20

69 51 44 37 26

109 81 69 59 41

157 117

l

8 6 5 4 3

Il

1 0

4 3 3 2 1

1/ 0 2/ 0 3/0 4/ 0

-

0 0 0 0

l l

2 l

3 3 2

I

l

I

8 7 6 5

17 15 12

0

6 5 4 3

13

l

1 1 1

22 19 16 13

35 30 25 21

51 43 36 30

250 300 350 400 500

-

0 0 0 0 0

0 0 0 0 0

1 1 0 0 0

1 1

1 1

3 2

l

l l l

l l l

6 5 5 4 3

8 7 6 6 5

11

1 1

4 3 3 3 2

17 15 13 12 10

25 21 19 17 14

600 700

-

0 0

0 0

0 0

0 0

l l

1 1

l l

3 2

4 3

.5

8 7

10

()

0

0

]]

8 4

3

9 7 4 3 l

()

10

l

8 7 6 4

()

11

10

l l l

11

9 8

JO

9 8 7 6 4

11

100

85 60

lL (continues)

70-790

NATIONAL ELECTRICAL CODE

2020 Edi tion

Annex C: Tables

I NFORMATIVE ANNEX C Table C.11

Continued Conduc tor Size (AWG/

kcmiI)

Type

THHN, THWN, THWN-2

FEP, FEPB, PFA, PFAH, TFE

PFA, PFAH, TFE PFA, PFAH, TFE, Z

z

Trade Size (Me tric Designator)

% (12)

(16)

'Y. (21)

1 (27)

1Y.. (35)

Y,

l Y,

(41)

2 (53)

750 800 900

-

0 0 0

0 0 0

0 0 0

0 0 0

0

IOOO 1250 1500 1750 2000

-

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

14 12 10 8 6

-

11 8 5 3

21 15 9 5 4

34 25 15 9 6

60 43 27 I6 11

82 59 37 21 I5

13.5

4 3 2

2 I

4 3 3

l

-

l

7 6 5 3

1/ 0 2/ 0 3/0 4/ 0

-

0 0 0

l l l l

l l

3 2

1

250 300 350 400 500

-

0 0 0 0 0

0 0 0 0 0

600 700 750 800 900 IOOO

-

0 0 0 0 0 0

14 12 10 8

-

6 4 3 2

-

2Y,

(63)

4 (103)

5 (129)

3 (78)

3Y. (91 ) 3 3 3

4 4 3

6 6 6

IO

3 2

7 6

l l l

5 4 3 3 3

.')

6 (155)

I I l

l l l

2 2

l l

l l l l l

l l l l l

2

62 36 26

193 141 89 51 37

299 2I8 137 79 57

401 293 184 106 77

517 377 238 137 99

815 594 374 2I6 156

1178 859 54I 312 225

9 8 7 5

16 13 11 8

22 19 16 12

35 30 25 18

47 40 33 25

61 51 43 32

96 81 68 50

I38 11 7 98 73

7 6 5 4

10 8 7 6

15 I3

l I

4 3 3 2

9

21 17 14 12

27 22 18 15

42 35 29 24

61 51 42 35

I

4 4 3 3 2

7 6 5 5 4

IO 8 7 6 5

12

l l l l

3 3 2

0 0

l l l l l

9 8 7

20 17 15 13 11

28 24 21 19 16

0 0 0 0 0 0

0 0 0 0 0 0

0 0 0 0 0

1 1 1 1 1 0

l l l

l l l l l l

3 3 2 2 2 l

4 4 3 3 3 3

5 5 4 4 4 3

9 8 7 7 6 6

13 11 11 LO 9 8

11 8 6 3

20 15 10 6

33 24 17

79 58 41 24

131

10

58 42 30 17

188 137 98 56

290 212 152 87

389 284 204 117

502 366 263 150

790 577 414 237

1142 834 598 343

2

4 3 2

12 8 7 6

17 12 IO 8

28 19 16 13

40 28 23

l

7 5 4 3

19

62 43 36 30

83 58 48 40

107 75 62 51

169 ll 8 98 8I

244 170 142 117

l

I l l l l

l l l

l l

l l l l

l

l l

I 0 0 99

l l

1 1 l

96

69 39

l

11

l l l l

11

9

8

4 4

l

-

I

I

2

4

5

9

13

20

28

36

56

81

1/ 0 2/ 0 3/ 0 4/ 0

-

l

I

3 3 2

4 4 3 2

8 6

ll

()

l l l l

4

9 7 6

17 14 12 9

23 I9 I6 13

30 24 20 16

47 39 32 26

68 56 46 38

14 I2 10 8 6

-

13 9 6 3 2

24 17 LO 6 4

40 28 17

70 49 30 19

7

13

158 112 69 43 30

226 160 98 62 43

3.50 248 152

11

95 68 41 26 18

67

469 333 204 129 90

605 429 263 166 116

952 675 414 261 184

1376 976 598 378 265

4 3 2

-

l l l l

3 2

5 4 3 2

9 6 5 4

12 9 7 6

21 15 12 IO

30 22 LS 14

46 34 28 23

62 45 38 30

80 58 49 39

126 92 77 62

183 133

l

0 0

l l

l l l

l

.5

96

l ll

90 (continues)

2020 Edition

NATI ONAL ELECTRICAL CODE

70-791

Annex C: Tables Table C.11

INFORMATIVE ANNEX C

Continued Trade Size (Metric Designator)

Conductor Size Type

XHHW,ZW, XHHW-2,XHH

XHHW, XHHW-2 , XHH

(AWG/ kcrnil)

% (12)

Y,

(16)

% (21)

1 (27)

l Y. (35)

1Y2 (41)

2 (53)

2Y2 (63)

3 (78)

3Y, (91 )

4 (103)

5 (129)

6 (155)

14

24 18 13 7 5

42 32 24 13 LO

57 44 32 18 13

94 72 54 30 22

135 103 77 43 32

209 160 119 66 49

280 215 160 89 66

361 277 206 115 85

568 436 325 181 134

822 631 470 261 193

4 3 3

7 6 5

9 8 7

16 13 ll

23 19 16

35 30 2.5

48 40 34

61 52 44

97 82 69

140 118 99

14 12 10 8 6

-

8 6 4 2

4 3 2

-

l l l

2

l

-

l

l

l

3

5

8

12

19

25

32

51

74

-

l

0 0 0

l l l

l l

3 2 l l

4 3 3 2

7 6 5 4

10 8 7 6

16 13

21 17 14 12

27 23 19 15

43 36 30 24

62 52 43 35

250 300 350 400 500

-

l

l

5 4 3 3 2

7 6 5 5 4

13

1 1 1 1

3 3 2 l

IO

l l

8 7 6 5

11

9 8 7

20 17 15 13 11

29 25 22 19 16

600 700 750 800 900

l l 1 1 1

3 3 2 2 2

4 4 3 3 3

5 5 4 4 4

9 8 7 7 6

13 10 9

1000 1250 1500 1750 2000

3

3 3 2 1 1

6 4 4 3 3

8 6 5 5 4

1/ 0 2/ 0 3/0 4/ 0

l

11

8 4 3 l

l

l

l l

0 0 0 0 0

0 0 0 0 0

l 1 1 0 0

-

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

l 0 0 0 0

-

()

0 0 0 0 0

()

0 0 0 0 0

()

0 0 0

()

0 0 0

l l

l

11

9

1 1

l l

l

l

1 1

1 1

0 0 0 0 0

l l I

1

0 0

1 1

1 1 l l l

l I

l

l l l

11 ll

FIXTURE WIRES

RFH-2, FFH-2, RFHH-2

18 16

-

8 6

14 12

23 19

40 33

54 46

90 76

129 109

200 169

268 226

346 292

545 459

788 664

SF-2, SFF-2

18 16 14

-

10 8 6

17 14 12

29 24 19

50 42 33

69 57 46

114 94 76

163 135 109

253 209 169

338 280 226

436 361 292

687 568 459

993 822 664

SF-I, SFF-1

18

-

17

31

51

89

122

202

289

447

599

772

1216

1758

18 16

-

13 10

23 18

38 30

66 53

90 73

149 120

213 172

330 266

442 357

570 460

898 725

1298 1048

RFH-1, TF, TFF, XF,XFF

14

-

8

14

24

42

57

94

135

209

280

361

568

822

TFN, TFFN

18 16

-

20 16

37 28

60 46

105 80

144 110

239 183

341 261

528 403

708 541

913 697

1437 1098

2077 1587

PF, PFF, PGF, PGFF, PAF, PTF, PTFF, PAFF

18 16 14

-

19 15 IL

3.5 27 20

57 44 33

100 77 58

137 106 79

227 175 131

323 250 188

501 387 290

671 519 389

865 669 502

1363 1054 790

1970 1523 1142

ZF, ZFF, ZHF

18 16 14

-

25 18 13

45 33 24

74 54 40

129 95 70

176 130 95

292 216 158

417 308 226

646 476 3.50

865 638 469

ll 16 823 605

1756 1296 952

2539 1873 1376

KF-2, KFF-2

18 16 14 12 10

-

38 26 18 12 8

67 47 31 22 14

111 77 52 36 24

193 135 91 63 42

265 184 124 86 57

439 306 205 143 94

626 436 293 204 135

969 676 454 316 209

1298 905 608 423 280

1674 1168 784 546 361

2634 1838 1235 859 .568

3809 2657 1785 1242 822

KF-l, KFF-1

18

-

44

78

128

223

305

506

722

ll 18

1498

1931

3040

4395

XF, XFF

(continues)

70-792

NATIONAL ELECTRICAL CODE

2020 Edi tion

Annex C: Tables

INFORMATIVE ANNEX C Table C.ll

Continued Conduc tor Size

Type

(AWG/ kcmil)

16 14 12 10 XF, XFF

12 10

Trade Size (Metric Designator)

% (12)

(16)

'Y. (21)

1 (27)

1Y.. (35)

(41)

2 (53)

(63)

3 (78)

3Y. (91)

4 (103)

5 (129)

6 (155)

-

31 20 13 9

55 37 24 16

90 60 40 26

157 105 70 45

214 144 95 62

355 239 158 103

507 341 226 148

785 528 3.50 229

I052 708 469 306

1357 913 605 395

2136 1437 952 622

3088 2077 1376 899

-

4 3

8 6

13

22 17

30 24

50 39

72 56

112 87

150 117

193 150

304 237

439 343

Y,

IO

l Y,

2Y,

Notes: I. This table is for concentric so-anded conductors only. For compact stranded conductors, Table C. lO(A) should be used. 2. Two-hour fire-rated RHH cable has ceramifiable insulation, which has much larger diameters than other RHH wires. Consult manufacturer's conduit fill tables. *Types RHH, RHW, and RHW-2 without omer covering.

2020 Edition

NATIONAL ELECTRICAL CODE

70-793

Annex C: Tables

INFO RMATIVE ANNEX C

Table C.ll(A) Maximum Number of Conductors or Fixture Wires in Rigid PVC Conduit, Schedule 40 and HDPE Conduit (Based on Chapter 9: Table I, Table 4, and Table 5A) Conductor Size

Type

Trade Size (M etric Designator)

(AWG/

'Ya

Y,

Yi

1

I Y,

IV,

2

2Y,

3

3 Y,

4

5

kcmil)

( 12)

( 16)

(21)

(27)

(35)

(41)

(53)

(63)

(78)

(91 )

(103)

(129)

6 ( 155)

11

37 28 21 15

7

11

57 44 33 24 17

76 59 44 32 23

98 76 57 42 29

155 119 89 66 46

224 173 129 95 67

20 16 14 12

2.5 21 18 15

40 34 29 24

58 49 42 35

9 8 7 6 5

12 10 9 8 7

19 16 15 13 Ll

27 24 21 19 16

4 4 3 3 3

5 5 5 4 4

9 8 7 6 6

13 12 11 9 9

64 40 28 21

-

-

86 53 38 29

L11 68 49 37

175 108 77 58

253 156 1 L2 84

18 15 12 LO

24 20 17 14

31 26 22 18

49 41 34 28

59 50 41

8 7 6 5 4

11 9 8 7 6

14 L2 LO 9 8

22 19 L7 L5 13

32 28 24 22 18

COMPACT CONDUCTORS

THW, THW-2, THHW

THHN, THWN, THWN-2

l

-

1 1 1 1 1

1/ 0 2/ 0 3/0 4/ 0

-

0 0 0 0

250 300 350 400 500

-

0 0 0 0 0

0 0 0 0 0

600 700 750 900 LOOO

-

0 0 0 0 0

0 0 0 0 0

8 6 4 2 1

-

8 6 4 2

-

2 1 1

6 5 3 2 1

11 9 6 5 3

15 12 9 6 4

26 20 15

9

l.')

8

1

4 3 3 2

5

I

3 2 1 1

6

L

1 1 1

5 4

7 5

12 10 9

1 1 1 0 0

1 1 1 1

1 1 1

3 2 2

7 6 5

l

l

l

1

1

4 4 3 3 2

0 0 0 0 0

1 0 0 0 0

1 1 1 1

1 1 1 1 1

I l l I I

3 3 2 2

4

3 l l l l l

4 2

-

-

13 8 5 4

I

I I

7 4 3 2

l

17 11 8 6

5

4

l

-

-

29 18 13 9

41 2.5 18 14

8 7

12 9

5

8

4

6

3 3 3 2 1

5 4 4 3 2 l l l l

4 3 3 2 2

5 4 4 3 3

6 5 5 4 4

LO 9 8 7 6

1.5

1

1 1 1 1 1

-

1/ 0 2/ 0 3/0 4/ 0

-

1 0 0

I I I

1 1 1

3 3 2

0

L

I

l

5 4 3 3

250 300 350 400 500

-

0

0 0 0 0 0

1 1 1 1 0

1 1 1

1 1 1

l

l l

600 700 750 900 LOOO

-

0 0 0 0

0 0 0 0 0

0 0 0 0 0

1 1 0 0

8

-

3 1 1 1 1

.5

14 11 8 5 4

20 L5 LI 8 6

33 25 18 13 9

47 35 25 18 14

73 55 40 28 2L

99 73 53 38 29

127 94 68 49 37

200 149 108

l I

8 6 4 3 2

58

290 2L5 156 112 84

1/ 0 2/ 0 3/0 4/ 0

-

1

l I I l

1 L L 1

3 3 2

8 7 5 5

12 10 8 7

18

l

5 4 3 3

12 10

24 20 17 14

31 26 22 L8

49 42 34 29

72 60 50 42

250 300 350 400 500

-

L

1 1 1 1

1 1 1 1

l

l

4 3 3 2 1

5 4 4 3 3

8 7 6 5 4

11 9 8 7 6

L4 L2 LI 10 8

23 19 17 15 L3

33 28 25 22 L8

XHHW, XHH W-2

6 4 2 I

0 0 0

0

0

l

0 ()

0 0 0 0

0

4 2

0 0 0 0 0

I I

1 0

1 l

1 1 1 l

'.~

l.')

77

72

13 12 LO 9

(continues)

70-794

NATIONAL ELECTRICAL CODE

2020 Edi tion

Annex C: Tables

INFORMATIVE ANNEX C Table C. ll (A)

Continued Conduc tor Size

Type

(AWG/ kcmil)

Trade Size (Metric Designator)

%

Y,

'Y.

(12)

(16)

(21)

1 (27)

1Y.. (35)

l Y, (41)

2 (53)

I I l 600 0 0 0 l 1 l 700 0 0 0 750 0 0 0 1 1 1 900 0 0 0 I I 0 1000 0 0 0 I I 0 Defini tion: Compact stmnding is the result ofa manufacturing process where the strnnded conductor is compressed to the extent that the interstices (voids between su-and wires) are virtually e liminated.

2020 Edition

NATIONAL ELECTRICAL CODE

2Y, (63) 2 I I I I

3 (78)

3Y. (91 )

4 (103)

5 ( 129)

6 ( 155)

4 3 3 2 2

5 4 4 3 3

6 5 5 4 4

10 9

15 13 12 10

8 7 6

9

70-795

Annex C: Tables

INFO RMATIVE ANNEX C

Table C.12 Maximum Number of Conductors or Fixture Wires in Type A, Rigid PVC Conduit (Based on Chapter 9: Table 1, Table 4, and Table 5) Conductor Size

Type

Trade Size (Metric Designator)

(AWG/

'Ya

Y,

Yi

1

I Y,

IV,

2

2Y,

3

3 Y,

4

5

6

kcmil)

( 12)

( 16)

(21)

(27)

(35)

(41)

(53)

(63)

(78)

(91 )

(103)

(129)

(155)

CONDUCTORS

RHH, RHW, RHW-2

14 12 10 8 6

-

5 4 3

4 3 2

I I l

l

-

0

1/ 0 2/ 0 3/0 4/ 0

-

0 0 0 0

250 300 350 400 500

-

0 0

600 700 750 800 900 LOOO

l l

9 7 6 3 2

14 12 10 5 4

24 20 16 8 6

31 26 21 11 9

49 41 33 17 14

74 61 50 26 21

112 93 75 39 31

146 121 98 51 41

187 155 125 65 52

-

-

l l l l

3 3 2

5

7 6 5 3

11 9 8 5

16 14 12 8

24 21 18 12

32 28 24 16

41 36 31 20

-

-

l l l

l l l l

2

3 2

7 6 5 4

10

14 12

l l

5 4 3 3

9

18 15 13 11

-

-

l l

l l l l l

l l l l l

3 3 2 2

5 4 4 3 3

6 6 5 5 4

8 7 7 6 5

-

-

l l l l

I l l l l

l l I I l

2 2

3 3 3 3 2

4 4 4 3 3

-

-

l l

I l l

2

3 2

1

1

l l

l

l

1

-

-

0

l l l l l

0

l

4 4 2 l l l

9 8 7

10

0

0 0 0 0 0

0 0 0

l l l l l

-

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

0

1250 1500 1750 2000

-

0 0 0

0 0 0 0 0

0 0 0 0

0 0 0 0 0

0 0 0 0 0

TW, THHW, THW, THW-2

14 12 10 8

-

11

18 14 10 6

31 24 18 10

51 39 29 16

67 51 38 21

10.5 80 60 33

157 120 89 50

235 181 135 75

307 236 176 98

395 303 226 125

-

-

RHH*, RHW*, RHW-2*

14 12 10 8

-

7 6 4 2

12

20 16 13 7

34 27 21 12

44 35 28 16

69 56 44 26

104 84 65 39

157 126 98 59

204 164 128 77

262 211 165 98

-

-

6 4 3 2

-

l l I l l

3 2

6 4 4 3

9 7 6 5 3

13 9 8 7 5

20 15 13 11 7

30 22 19 16 11

45 33 29 24 17

59 44 37 32 22

75 56 48 41 29

-

-

1/ 0 2/ 0 3/0 4/ 0

-

l

l l l l

l l l l

3 2

4 3 3 2

6 5 4 4

10 8 7 6

14 12 10 9

19 16 13 11

24 21 17 14

-

-

250 300 350 400 500

-

0 0 0 0 0

l l l l

1

3 2 2

0

1 1

l l l l l

l l

4 4 3 3 2

7 6 5 5 4

9 8 7 6 5

12 10 9 8 7

-

-

600 700

-

0 0

0 0

l l

l l

I I

l l

3 3

4 4

.5 .5

-

-

TW, THW, THHW, THW-2, RHH*, RHW*, RHW-2*

l

0 0

()

0 8 6 3

0 0 0 0 0 ()

0 0 () ()

10

8 4

l l l

()

l

l l l l

0 ()

l

l l I

l l

-

-

(continues)

70-796

NATIONAL ELECTRICAL CODE

2020 Edi tion

Annex C: Tables

I NFORMATIVE ANNEX C Table C.12

Continued Conduc tor Size (AWG/ kcmil)

Type

THHN, THWN, THWN-2

FEP, FEPB, PFA, PFAH, TFE

PFA, PFAH, TFE PFA, PFAH, TFE, Z

z

Trade Size (Metric Designator)

% (12)

(16)

'Y. (21)

1 (27) 0 0

Y,

1Y.. (35)

l Y,

(41)

2 (53)

2Y,

(63)

3 (78)

3Y. (91 )

4 (103)

5 (129)

6 (155)

0

0 0

l l l

l l l

l l l

3 2 2

3 3 3

4 4 4

-

-

0 0 0 0 0

l

l l l l

1

l l l l

3 3 2

0 0

I l l l l

3

0 0 0 0

l l I

0

0 0 0 0 0

-

-

16 11 7 4 3

27 19 12 7 5

44 32 20 12 8

73 53 33 19 14

96 70 44 25 18

150 109 69 40 28

225 164 103 59 43

338 246 155 89 64

441 321 202 117 84

566 412 260 150 108

-

-

l l l l

3 2

8 7 6 4

9 8 6

17 15 12 9

26 22

l l

5 4 3 2

11

l

-

39 33 28 21

52 44 37 27

66 56 47 35

-

-

1/ 0 2/ 0 3/0 4/ 0

-

l l

0 0

l l l

2 1 1

4 3 2

l

I

8 6 5 4

11 10 8 6

17 14 12

1

5 4 3 3

10

23 19 16 13

29 24 20 17

-

-

250 300 350 400 500

-

0 0 0 0 0

1 0 0 0 0

1 1

l l I l l

2

3 3 2 2 l

5 4 4 3 3

8 7 6 5 4

10 9 8 7 6

14 12 10 9 7

-

-

600 700 750 800 900 1000

-

0 0 0 0 0 0

0 0 0 0 0 0

0 0 0 0 0 0

l l l l

l l

l l l

2 1 1

0 0

1 1

l l

1

3 3 3 3 2 2

5 4 4 4 3 3

6 5 5 5 4 4

-

-

14 12 10 8

-

15 11 8 4

26 19 13 8

43 31 22 13

70 51 37 21

93 68 48 28

146 106 76 44

218 159 114 65

327 239 171 98

427 312 224 128

549 400 287 165

-

-

-

6 4 3 2

-

3

5 4 3 2

9 6 5 4

15

20 14 11 9

31 21 18 15

46 32 27 22

70 49 40 33

91 64 53 44

117 82 68 56

-

-

750 800 900

-

0 0 0

0 0 0

1000 1250 1500 1750 2000

-

0 0 0 0

0 0 0 0

0

14 12 10 8 6

-

4 3 2

l

1 l

l l l

I

10

8 7

l l l l

1 1 1 l

l

19

14

I l

-

I

-

1

1

3

5

6

IO

15

23

30

39

-

-

1/ 0 2/ 0 3/0 4/ 0

-

l

1

2

1 1 0

l l l

l l

4 3 3 2

5 4 3 3

8 7 6 5

13 10 9 7

19 16 13 11

25 21 17 14

32 27 22 18

-

-

14 12 10 8 6

-

18 13 8 5 3

31 22 13 8 6

.52 37 22 14

85 60 37 23 16

112 79 48 30 21

17.5 124 76 48 34

262 186 114 72 50

395 280 171 108 76

.515 365 224 141 99

661 469 287 181 127

-

-

4 3 2

-

2

4 3 2 1

7 5 4 3

11

15

8 7 5

11

23 17 14 11

35 25 21 17

.52 38 32 26

68 50 41 33

88 64 53 43

l

l

1 1

1

10

9 7

-

-

(continues)

2020 Edition

NATI ONAL ELECTRICAL CODE

70-797

Annex C: Tables Table C.12

INFORMATIVE ANNEX C

Continued Trade Size (Metric Designator)

Conductor Size Type

XHHW,ZW, XHHW-2,XHH

(AWG/ kcrnil)

14 12 10 8

Y,

(16)

% (21)

1 (27)

l Y. (35)

1Y2 (41)

2 (53)

2Y2 (63)

3 (78)

3Y, (91)

4 (103)

5 (129)

6 (155)

-

II

8 6 3 2

18 14 10 6 4

31 24 18 10 7

51 39 29 16 12

67 51 38 21 15

105 80 60 33 24

157 120 89 50 37

235 181 135 75 55

307 236 176 98 72

395 303 226 125 93

-

-

4 3 2

-

1 1

3 2

l

l

5 4 3

8 7 6

11 9 8

18 15 12

26 22 19

40 34 28

52 44 37

67 57 48

-

-

1

-

1

1

3

4

6

9

14

21

28

35

-

-

-

1 1 0 0

l l l l

2

4 3 2

8 6 5 4

12 10 8 7

18 15 12 10

23 19 16 13

30 25 20 17

-

-

l

5 4 3 3

250 300 350 400 500

-

0 0 0 0 0

l

l

1 1

l l l l l

2 1 1 1 1

3 3 3 2

5 5 4 3 3

8 7 6 5 4

ll

0 0 0 0

14 12 10

-

8

-

600 700 750 800 900

-

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

l l l l

1 1

2

3 3 3 3 2

5 4 4 4 3

6 5 5 5 4

-

-

1000 1250 1500 1750 2000

-

()

0 0 0

()

2 1

3 2

l l l

l l l

4 3 2 2 1

-

-

6

XHHW, XHHW-2 , XHH

% (12)

1/ 0 2/ 0 3/0 4/ 0

()

() () ()

() ()

l l l

l

1

()

0 0 0

0 0 0 0 0 0

l

l

l l l

1 1

1 1

1 ()

l l I l

()

()

()

0

l

1 1 1 1 l

1 l l

9 8 7 6

9

-

-

-

FIXTURE WIRES

RFH-2, FFH-2, RFHH-2

18 16

-

10 9

18 15

30 25

48 41

64 54

100 85

150 127

226 190

295 248

378 3 19

-

-

SF-2, SFF-2

18 16 14

-

13 9

22 18 15

37 31 25

61 51 41

81 67 54

127 105 85

189 157 127

285 235 190

372 307 248

477 395 319

-

-

18

-

23

40

66

108

143

224

335

504

658

844

-

-

18 16

-

17 14

29 24

49 39

80 65

105 85

165 134

248 200

372 300

486 392

623 503

-

-

SF-I, SFF-1 RFH-1 , TF, TFF, XF, XFF

ll

14

-

ll

18

31

51

67

105

157

235

307

395

-

-

TFN, TFFN

18 16

-

28 21

47 36

79 60

128 98

169 129

265 202

396 303

596 455

777 594

998 762

-

-

PF, PFF, PGF, PGFF, PAF, PTF, PTFF, PAFF

18 16 14

-

26 20 15

4.5 34 26

74 58 43

122 94 70

160 124 93

251 194 146

376 291 218

565 437 327

737 570 427

946 732 549

-

-

ZF, ZFF, ZHF

18 16 14

-

34 25 18

57 42 31

96 71 52

157 116 85

206 152 112

324 239 175

484 357 262

728 537 395

950 701 5 15

1220 900 661

-

-

KF-2, KFF-2

18 16 14 12 10

-

51 36 24 16

86 60 40 28 18

144 101 67 47 31

235 164 110 77 51

310 216 145 101 67

486 339 228 158 105

727 507 341 237 157

1092 762 512 356 23.5

1426 994 668 465 307

1829 1276 857 596 395

-

-

XF, XFF

ll

(continues)

70-798

NATIONAL ELECTRICAL CODE

2020 Edi tion

Annex C: Tables

I NFORMATIVE ANNEX C Table C.12

Continued Conduc tor Size

Type

KF-1, .KFF-1

(AWG/ kcmil)

18 16 14 12 10

XF,XFF

12 IO

Trade Size (Metric Designator)

% (12)

(16)

'Y. (21)

1 (27)

1Y.. (35)

(41)

2 (53)

(63)

3 (78)

3Y. (91 )

4 (103)

-

59 41 28 18 12

100 70 47 31 20

166 117 79 52 34

272 191 128 85 55

357 251 169 112 73

561 394 265 17.5 11.5

839 589 396 262 171

1260 886 596 395 258

1645 1156 777 515 337

2111 1483 998 661 432

-

-

-

6 4

10 8

16 13

27 21

35 28

56 44

84 65

126 98

164 128

2 11 165

-

-

Y,

l Y,

2Y,

5 (129)

6 (155)

Notes: 1. This table is for concentric su-anded conductors only. For compact stranded conductors, Table C.11 (A) should be tL~ed. 2. Two-hour fire-rated RHH cable has ceramitiable insulation, wh ich has much larger d iameters than other Rl-lH wires. Consu lt manufacturer's conduit fill tables. *Types RHH, RHW, and RI-fW-2 without outer covering.

2020 Edition

NATIONAL ELECTRICAL CODE

70-799

Annex C: Tables

INFO RMATIVE ANNEX C

Table C.12(A) Maximum Number of Conductors or Fixture Wires in Type A, Rigid PVC Conduit (Based on Chapter 9: Table 1, Table 4, and Table 5A) Conductor Size

Type

Trade Size (Metric Designator)

(AWG/

'Ya

Y,

Yi

1

I Y,

IV,

2

2Y,

kcmil)

( 12)

( 16)

(21)

(27)

(35)

(41)

(53)

(63)

3 (78)

3 Y, (91 )

4 (103)

5 (129)

6 (155)

COMPACT CONDUCTORS

THW, THW-2, T H HW

TH HN, THWN, THWN-2

XHHW, XHH W-2

3 2 1

l

-

l l

5 4 3 1 1

8 6 5 3 2

14 10 8 6 4

18 14 10 7 5

28 22 16 12 8

42 33 24 18 13

64 49 37 27 19

84 65 48 36 25

107 83 62 46 32

-

-

1/ 0 2/ 0 3/0 4/ 0

-

l l

1 1

0 0

I I

l l l l

3 3 2 1

4 4 3 3

7 6 5 4

11 9 8 6

16 14 12 10

21 18 15 13

28 23 20 17

-

-

250 300 350 400 500

-

0 0 0 0 0

1 0 0 0 0

l l l I l

l l l l l

I l l l

3 3 2 2 1

5 4 4 3 3

8 7 6 5 4

10 9 8 7 6

13 11 LO 9 8

-

-

600 700 750 900 LOOO

-

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

l

1 1 0 0

l l l

l l l

2 1 1

1

1 l

I I

.5 4 4 3 3

6 5 5 4 4

-

-

l

3 3 3 2 2

8 6 4 2 l

-

1/ 0 2/ 0 3/0 4/ 0

8 6 4 2

-

-

-

-

-

-

-

-

-

15 9 7 5

20 12 7

32 20 14 10

48 30 21 16

72 45 32 24

94 58 42 31

121 75 54 40

-

-

9 6 4 3

6 5 4 3

9

13

7 6 5

11

20 17 14 11

27 22 18 15

34 28 24 19

-

-

12 9 8 7

15 13 11 LO 9

-

-

-

l l

5 3 2

1

I

-

1 1 1 0

I I I I

2 1 1

4 3 3 2

250 300 350 400 500

-

0 0 0 0 0

I I

1

1

2

0 0 0

l l l I

I I l

l l l I

4 3 3 2 2

6 5 4 4 '.~

9 8 7 6 5

600 700 750 900 1000

-

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

l l l l

l I I

l

1 1

1

0

I

l l

3 2 2 1 1

4 3 3 3 2

5 5 4 4 3

7 6 6 5 4

-

-

8 6 4 2

-

4 3

6 5 3 2

11

18 13 9 7 .5

23 17 12 9 7

37 27 20 14 LO

5.5 41 30 21 16

83 62 45 32 24

108 80 58 42 31

139 103 75 54 40

-

-

1/ 0 2/ 0 3/0 4/ 0

-

I l l

4 3 3 2

6 5 4 3

9

13

7 6 5

II

0

I I I I

20 17 14 12

27 22 18 15

34 29 24 20

-

-

250 300 350 400 500

-

0 0 0 0 0

I

1

l

2

1 0 0 0

1 1 1

1 1 1

I I

l

l

-

-

1

6 5 5 4 3

16 13 12

1

4 3 3 3 2

l

3

1

I I l

I

I

8 6 4 3 2 I I I

1

9

9 8

9 8

10

9

12

8

IO

7 6 5

9 8 7

11

9

-

-

(continues)

70-800

NATIONAL ELECTRICAL CODE

2020 Edi tion

Annex C: Tables

I NFORMATIVE ANNEX C Table C.12(A)

Continued Conduc tor Size

Type

(AWG/ kcmil) 600 700 750 900 1000

Trade Size (Metric Designator)

%

Y,

'Y.

( 12)

( 16)

(21)

1 (27)

1Y.. (35)

0 0 0

0 0 0 0 0

0 0 0 0 0

I l

-

0 0

l Y, (41)

I

2 (53)

l l

2Y, (63)

1

1 1

1

3 2 2

l 0

I I

I I

I I

3 (78)

3Y. (91 )

4 ( 103)

4

5 5 4 4

7 6 6 5 4

3 3 3 2

3

5 ( 129)

-

6 ( 155)

-

Definition: Compact stranding is the result of a manufacturing process where the stranded conductor is compressed to the extent th at the interstices (voids between strand wires) are virtually eli minated.

2020 Edition

NATIONAL ELECTRICAL CODE

70-801

Annex C: Tables

INFORMATIVE ANNEX C

Table C.13 Maximum Number of Conductors or Fixture Wires in Type EB, PVC Conduit (Based on Chapter 9: Table 1, Table 4, and Table 5 ) Conductor Size Type

Trade Size (Metric Designator) 1Y. (35)

(AWG/

Ya

~

o/,

kcmil)

(12)

(16)

(21)

-

-

-

-

-

-

-

-

-

-

-

-

l (27)

l~

2

2~

(41)

(53)

(63)

3~

3 ( 78)

(91)

4 (103)

5 (129)

6 (155)

ll9 98 79 41 33

155 128 104 54 43

197 163 132 69 55

303 251 203 106 85

430 357 288 151 I 21

26 23 20 13

34 30 26 17

43 38 33 21

66 58 50 33

94 83 72 47

II

10 8 7

15 13 ll 9

19 16 14 12

29 25 22 18

41 36 31 26

5 5 4 4 3

7 6 5 5 4

9 8 7 6 5

14 12 II

20 17 16 14 12

3 2 2 2 1

3 3 3 3 2

4 4 4 4 3

7 6 6 6 5

10

1 1 1 1 1

2 1 1 1 I

3 2 1 1 I

5 3 3 3 2

7 5 4 4 3

250 192 143 79

327 251 187 104

415 319 238 132

638 490 365 203

907 696 519 288

166 134 104 62

217 175 136 81

276 222 173 104

424 341 266 159

603 485 378 227

48 36 30 26 18

62 46 40 34 24

79 59 51 43 30

122 91 78 66 46

173 129

15 13

26 22 18 15

40 34 28 24

56 48 40 34

12 ll

19 17 15

27 24 21

CONDU CTORS

RHH,RHW, RHW-2

14 12 10 8 6 4 3 2 1 1/ 0 2/ 0 3/ 0 4/ 0 250 300 350 400 500 600 700 750 800 900 1000 1250 1500 1750 2000

TW,THHW, THW, THW-2

RHH*, RHW*, RHW-2*

14 12 10 8 14 12 10 8

-

-

-

-

-

-

-

-

-

-

-

-

-

53 44 35 18 15

-

II

-

-

-

10 9 6

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

5 4 4 3

-

-

-

-

-

2

-

I

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

TW,THW, THHW, THW-2, RHH*,

6 4 3 2

-

-

-

-

-

-

-

-

-

1

-

-

-

-

Rl--£\N*,

-

I/ 0 2/ 0 3/ 0 4/ 0

-

-

-

-

-

-

-

-

1 I I

-

1 1 I I 1

-

I 1 0 0 0 l ll

85 63 35 74 59 46 28

-

-

-

-

-

-

21 16 13

-

II

-

-

-

-

-

-

-

-

-

7 6 5 4

-

8

-

IO 9

9 9 8 7

lII

94 66

RHW-2*

250 300 350

-

-

-

-

3 3 2

-

9

20 17 14 12

-

7 6 6

10 8 7

-

-

-

II

9

(con tinues)

70-802

NATIONAL ELECTRICAL CODE

2020 Edi tion

Annex C: Tables

INFORMATIVE ANNEX C Table C.13

Continued

Conductor Size (AWG/

kcmil)

Type

Trade Size (Metric Designator)

Ys (12)

400 500

-

600 700 750 800 900

-

1000 1250 1500 1750 2000 THHN,THWN, THWN-2

14 12 10 8 6

l'l2

(35)

(41)

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

l

-

-

1 1 1

-

-

l

-

3\'2 (91)

4 (103)

5 (129)

6 (155)

5 4

7 5

8 7

13 11

19 16

3 3 3 3 2

4 4 4 3 3

6 5 5 4 4

9 8 7 7

13

(i

11 10 9

3 2 1

6 4 4 3 3

8 6 6 5 4

-

-

-

-

-

-

-

-

-

-

1

-

-

-

l

-

-

1

-

l

-

2 1 1 1

l

4 3 2 2

0

-

l

1

l

-

359 262 165 95 68

468 342 215 124 89

595 434 274 158 114

915 667 420 242 175

1300 948 597 344 248

42 36 30 22

55 46 39 29

70 59 50 37

107 91 76 57

153 129 109 80

24 20 17 14

31 26 21 18

48 40 33 27

68 56 47 39

22 19

31 27 24 21 18

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

1/ 0 2/ 0 3/ 0 4/ 0

-

-

-

-

-

1

2 1

3 (78)

-

-

1/ 0 2/ 0 3/ 0 4/ 0

2~

(63)

-

-

14 12 10 8

2 (53)

-

-

6 4 3 2 PFA, PFAH, TFE,Z

l Y..

(27)

l

600 700 750 800 900 1000

PFA, PFAH, TFE

l

(21)

4 3 2

250 300 350 400 500

FEP, FEPB, PFA, PFAH, TFE

-

x

'l2 (16)

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

159 116 73 42 30 19 16 13 10

4 3 3 2 1

-

8 7

11 JO

14 12

-

(i

8 7 6

ll

l7

6 5

10 8

15 12

4 3 3 3 3 2

5 4 4 4 3 3

6 6 5 5 4 4

10 9 8 8 7 (i

10 9

348 254 182 104

454 332 238 136

578 422 302 173

887 648 465 26fi

1261 920 fifiO 378

74 52 43 36

97 68 56 46

123 86 72 59

189 132 110 91

269 188 157 129

25

32

41

63

90

20 17 14 11

27 22 18 15

34 28 23 19

53 43 36 29

75 62 51 42

-

1

-

-

-

l l l

-

-

-

1

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

33 23 19 16

-

ll

-

-

-

-

-

-

-

-

-

-

-

-

-

-

9 7 6 5

-

-

-

-

-

-

18 15 13 10

-

-

-

-

-

-

-

-

ll

8 7 5 4

-

-

-

l

155 ll3 81 46

-

-

-

14 12 12 ]]

(continues)

2020 Edition

NATIONAL ELECTRICAL CODE

70-803

Annex C: Tables Table C.13

INFORMATIVE ANNEX C

Continued Conductor Size

Type

z

l Y..

rn

(35)

(41)

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

Ys

kcmil)

(12)

\12 (16)

-

-

-

-

-

-

-

-

-

-

-

14 12 8 6 4 3 2 l

14 12 10 8 6 4 3 2

XHHW, XHHW-2, XHH

l

(27)

(AWG/

lO

XHHW,ZW, XHHW-2, XHH

Trade Size (Metric D esignator)

l

l/ 0 2/0 3/0 4/ 0

Y.. (21)

-

2 (53)

2Yi! (63)

3 (78)

3\12 (91)

4 (103)

5 (129)

6 (155)

186 132 81 51 36

-

419 297 182 115 81

547 388 238 150 105

696 494 302 191 134

1069 759 465 294 206

1519 1078 660 417 293

-

-

24 18 15 12

55 4.0 34 27

72 53 44 36

92 67 56 45

142 104 86 70

201 147 122 99

250 192 143 79

327 251 187 104

415 319 238 132

638 490 365 203

907 696 519 288

-

59 42 36 30

77 56 47 39

98 71 60 50

150 109 92 77

213 155 131 llO

-

-

Ill

-

-

-

85 63 35

-

-

-

-

-

26 19 16 13

-

-

lO

-

22

29

37

58

82

-

-

-

-

-

8 7 6 5

19 16 13

25 20 17 14

31 26 22 18

48 40 33 27

69 57 47 39

-

9 7 6 6 5

11 8 8 6

15 12 11 IO 8

22 19 17 15 12

32 28 24 22 18

5 4 4 4 3

6 6 5 5 4

lO

-

4 3 3 3 3

9 8 8 7

14 12 12 11 10

-

2 l l l l

3 2 l 1

4 3 3 2 1

6 5 4 4 3

9 7 6 5 5

240 202

313 264

398 336

612 516

869 733

395 327 264

502 415 336

772 638 516

1096 907 733

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

l

-

600 700 750 800 900

-

4 3 3 2

-

-

-

l

-

-

1000 1250 1500 1750 2000

-

-

-

-

-

l 1 l l

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

250 300 350 400 500

-

-

-

1 l l

-

-

-

ll

l

-

0

-

-

107 90

-

-

303 250 202

lO

l

FIXTURE WIRES

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

134 l }] 90

RFH-2, FFH-2, RFHH-2

18 16

SF-2, SFF-2

18 16 14

-

-

-

SF-I, SFF-l

-

-

18

-

-

-

-

-

-

238

-

536

699

889

1366

1940

RFH-1, TF, TFF, XF, XFF

18 16

-

-

-

-

-

-

-

-

176 142

-

396 319

516 417

656 530

1009 814

1433 1157

XF, XFF

14

-

-

-

-

-

-

lll

-

250

327

415

638

907

TFN,TFFN

18 16

-

-

-

-

-

-

281 215

-

633 484

826 631

1050 802

1614 1233

2293 1751

(continues)

70-804

NATIONAL ELECTRICAL CODE

2020 Edi tion

Annex C: Tables

INFORMATIVE ANNEX C Continued

Table C.13

Conductor Size (AWG/ kcmil)

Type

Trade Size (Metric Designator)

Ys

'l2

x

l

l Y..

l'l2

( 12)

( 16)

(21)

(27)

(35)

(41)

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

PF, PFF, PGF, PGFF, PAF, PTF, PTFF, PAFF

18 16 14

-

-

-

ZF, ZFF, ZHF

18 16 14

-

-

KF-2, KFF-2

KF-1 , KFF-1

-

-

IS

-

16 14 12

-

10

-

-

18 16 14 12

-

-

-

-

10

XF,XFF

-

-

12 IO

-

-

-

-

2 (53)

2~

(63)

3 (78)

3\'2 (91)

4 (103)

5 (129)

6 (155)

600 464 348

783 606 454

996 770 578

1530 II83 887

2174 1681 1261

774 571 419

1010 745 547

1284 947 696

1973 1455 1069

2802 2067 1519

1161 810 544 378 250

151 5 1057 710 494 327

1926 1344 903 628 415

2959 2064 1387 965 638

4204 2933 1970 1371 907

1748 1228 826 547 358

2222 1562 1050 696 455

3414 2399 1614 1069 699

4850 3408 2293 1519 993

175 136

222 173

341 266

485 378

267 206 155

-

344 254 186

-

516 360 242 168

-

-

-

-

II l

-

-

-

596 419 281 186 122

-

1340 941 633 419 274

59 46

-

134 104

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

Notes: 1. This table is for concentric stranded conductors only. For compact stranded conductors, Table C.12 (A) should be used. 2. Two-hour fire-rated RHH cable has ceramifiable insulation, which has much larger diameters than othe r RHH wires. Consult manufacturer's conduit fill tables. 'Types RHH, RHW, and RHW-2 without outer covering.

2020 Edition

NATIONAL ELECTRICAL CODE

70-805

Annex C: Tables

INFO RMATIVE ANNEX C

Table C.13(A) Maximum Number of Conductors or Fixture Wires in Type EB, PVC Conduit (Based on Chapter 9: Table 1, Table 4, and Table 5A) Conductor Size

Type

Trade Size (Metric Designator)

(AWG/

'Ya

Y,

Yi

1

I Y,

IV,

2

2Y,

3

3 Y,

4

5

kcmil)

( 12)

( 16)

(21)

(27)

(35)

(41)

(53)

(63)

(78)

(91 )

(103)

(129)

6 ( 155)

-

30 23 17 13 9

-

68 52 39 29 20

89 69 51 38 26

113 87 65 48 34

174 134 100 74 52

247 191 143 105 74

8 6 5 4

-

17

-

-

23 19 16 14

29 24 21 17

45 38 32 27

64 54 46 38

11

14 12

30 26 24 2L 18

COMPACT CONDUCTORS

THW, THW-2, THHW

THHN, THWN, THWN-2

XHHW, XHH W-2

8 6 4 2 I

-

1/ 0 2/ 0 3/0 4/ 0

-

250 300 350 400 500

-

600 700 750 900 LOOO

-

8 6 4 2 1

-

1/ 0 2/ 0 3/0 4/ 0

-

250 300 350 400 500

-

600 700 750 900 LOOO

-

8 6 4 2 1

-

1/ 0 2/ 0 3/0 4/ 0

-

250 300 350 400 500

-

-

-

-

-

-

-

-

-

3 3 3 2 1

-

8 7 6 6

-

-

-

-

1 1 1 1 1

-

-

-

-

-

-

34 21 15

-

-

-

-

-

-

9 8 6

22 18

5

-

-

-

-

-

-

4 4 3 3 2

-

10 8 7 6

-

-

-

I 1 1 I I

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

!.')

12 10

11

5

8 7 6

LO 8

21 19 17 15 L2

4 3 3 3 2

.5 4 4 4 3

6 6 5 5 4

IO 9 8 7 7

14 13 12 10 9

-

-

-

77

LOO 62 44 33

L28 79 57 42

196 121 87 65

279 172 124 93

28 23 20 16

36 30 25 20

56 46 38 32

79 6.5 55 45

5

13 II 9 8 7

16 L4 L2 LI 9

25 22 L9 L7 14

35 31 27 24 20

-

4 4 4 3 3

6 5 5 4 3

7 6 6 5 4

Ll 10 9 8 7

16 14 14 Ll 10

39 29 21 15 Ll

-

88 65 47 34 25

Ll5 85 62 44 33

146 109 79 57 42

225 167 121 87 65

320 238 172 124 93

-

9 8 6

22 18

5

-

12

28 24 20 16

36 30 25 21

56 47 38 32

79 67 55 46

-

4 4 3 3 2

-

10 8 7 7 5

13 11 IO 9 7

L7 L4 L2

26 22 19 17 14

37 31 28 25 20

-

11

-

47 34 25

l.'>

L2

!.')

9

11

9

-

(continues)

70-806

NATIONAL ELECTRICAL CODE

2020 Edi tion

Annex C: Tables

I NFORMATIVE ANNEX C Table C.13(A)

Continued Conduc tor Size

Type

(AWG/ kcmil)

Trade Size (Metric Designator)

%

Y,

'Y.

(12)

(16)

(21)

1 (27)

1 Y.. (35)

l Y, (41)

2 (53)

600 700 750 900 1000 Definition: Compact stmndingis the result ofa manufacturing process where the strnnded conductor is compressed to the extent that the interstices (voids between su-and wires) are virtually e liminated.

2020 Edition

NATI ONAL ELECTRICAL CODE

2Y, (63)

3 (78)

3Y. (91 )

4 (103)

5 ( 129)

6 ( 155)

4 4

6 5 5 4 4

7 6 6 5 5

11 10 9

16 14

3 3 3

8 7

13 11 10

70-807

Annex C: Tables

INFORMATIVE ANNEX C

Table C.14 Nwnber of Type MC Cables Permitted in Cable Tray (3C Multiconductor MC Cable Non-Jacketed Assembly) (Based on fill in accordance with 392.9, Table 392.9, column 1, ampacity in accordance with 392.11) Ventilated Tray Width [mm (in.)] Conductor Insulation Type

Conductor Size (AWG/kcmil)

50 (2)

100 (4)

150 (6)

200 (8)

300 (12)

400 (16)

450 (18)

500 (20)

600 (24)

750 (30)

900 (36)

Cable Diameter

110 83 62 50 34 23 21 I8 16 I4 13 10 IO 9 8 8 7 7 6 6 5 5 5 4

124 93 70 56 39 26 23 20 18 I6 I4 11

138 104 78 63 43 29 26 22 20 18 I6 13 I2 II 10 IO 9 8 8 7 7 6 6 6

165 124 94 75 52 35 31 27 24 22 19 15 15 13 12 12 11 IO 9 9 8 8 7 7

206 160 119 96 66 45 40 34 30 28 24 20 I9 I7 16 15 14 13 I2

248 192 149 116 79 55 48 4I 36 34 29 24 22 20 19 18 17 16 15 14 I3 I2 12

0.46 0.53 0.6I 0 .68 0.82 0.99 l.05 l.I3 l.2 1.25 l.34 l.49 1.57 I .74 1.86 l.96 2 .11 2 .24 2 .38 2.52 2 .67 2 .85 2 .99 3 .25

T I-lHN

14 27 13 20 12 10 10 7 I5 8 6 I2 4 6 8 4 2 5 2 5 3 2 2 4 I 4 2 1 3 I /0 2/0 3 2 3/0 2 4/ 0 250 2 300 1 2 350 1 2 400 0 l 500 0 600 0 l 700 0 1 750 0 800 0 900 0 1 1 1000 0 Note: Single conductor diameters were obtained from

70-808

41 31 23 I8 I3 8 7 6 6 5 4 3 3 3 3 3 2 2 2 2 2 2

82 55 41 62 3I 47 25 37 17 26 11 17 IO 15 9 13 12 8 7 11 6 9 7 5 7 5 4 6 4 6 4 6 3 5 3 5 3 4 4 3 2 4 2 4 l 2 3 l 2 3 Chapter 9, Table 5.

II

10 9 9 8 7 7 7 6 6 5 5

11 ll

IO IO 9

11

NATIONAL ELECTRICAL CODE

2020 Edi tion

Annex C: Tables

INFORMATIVE ANNEX C

Table C.15 Number of Type MC Cables Permitted in Cable Tray (4C Multiconductor MC Cable Non-Jacketed Assembly) (Based on fill in accordance with 392.22, Table 392.22(A), column 1, ampacity in accordance with 392.80) Conductor Insulation Type

Conductor Size (AWG/ kcmil)

Ventilated Tray Width [mm (in.)] 50 (2)

100 (4)

150 (6)

200 (8)

225 (9)

300 (12)

400 (16)

450 (18)

500 (20)

600 (24)

750 (30)

900 (36)

Cable Diameter

10 8 6 5 3 2 2 2

23 18 14

37 28 21 17 12 8 7 5 5 5 3 3 3 2 2 2 2 2 2 2

47 37 27 22 15 10 9 7 6 6 4 4 4 3 3 3 3 2 2 2 2 2 2

55 43 32 25 17

73 57 42 33 23 15 13

94 73 54 43 30 19 17 14 12 12 9 7 8 7 7 6 6 5 5 5 4 4 4 3

llO

120 93 69 55 38 25 22 18 16 15 10 10

146 ll4 84 67 46 30 27 21 19 19 14 12 12

9

ll

8 8 8 7 6 6 5 5 5 4

10 9 8 8 8 7 6 6 5

183 142 105 84 58 38 33 27 24 24 17 15 15 14 13 12 12

219 171 127 100 69 45 40 32 29 28 21 17 18 17 15 15 14 13 12 12 10 9 9 8

0.494 0.56 0.65 0.73 0.88 1.09 1.155 1.29 l.355 l.375 l.608 1.75 1.97 2.0l 2.255 2.39 2.46 2.71 2.92 2.98 3.34 3.71 3.98 4.15

TI-IHN

14 12 lO 8 6 4 3 2 1 1/ 0 2/ 0 3/ 0 4/ 0 250 300 350 400 500 600 700 750 800 900 1000

2020 Edition

1 0 0 0 0 0 0 0 0 0 0 0

NATIONAL ELECTRICAL CODE

ll

7 5 4 3 3 3 2 2 2 l l

1

1 1 1 1 0

]

l

ll

10 8 7 7 5 4 4 4 3 3 3 3 3 3 2 2 2 2

ll

10 9 7 6 6 5 5 5 4 4 4 4 3 3 3 2

85 63 50 35 23 20 16 15 ]4 10 9 9 8 7 7 7 6 6 6 5 4 4 4

]]

JO

ll

10 10 8 8 7 7

70-809

Annex C: Tables

INFORMATIVE ANNEX C

Table C.16 Nwnber of Type TC Cables Permitted in Cable Tray (3C MulticonductorTC Cable Assembly) (Based on fill in accordance with 392.22, Table 392.22(A), column 1, ampacity in accordance with 392.80) Conductor Insulation Type

Conductor Size (AWG/ kcmil)

Ventilated Tray Width [mm (in.)] 50 (2)

100 (4)

200 (8)

225 (9)

300 (12)

400 (16)

450 (18)

500 (20)

600 (24)

750 (30)

900 (36)

Cable Diameter

41 32 24 19 13 13 ll 9 6 6 5 4 3 3 3 3 2 2 2 2 2 2

52 41 30 24 17 16 14 12 8 8 7 6 5 4 4 4 3 3 3 3 2 2 2 2

61 47 35 29 20 19 16 14 10 9 8 7 5 5 4 4 4 4 3 3 3 3 2 2

81 63 47 38 26 26 22 18 13 12 10 9 7 6 6 6 5 5 4 4 4 4 3 3

104 81 60 49 34 33 28 23 17 15 13 12

122 95 71 57 40 38 32 27 19 18 16 13

133 104 77 62 43 42 35 30 21 20 17 15 12 ll 10 10 9 8 8 7 7 6 6 6

162 126 94 76 53 51 43 36 26 24 21 18 15 13 12 12 ll 10 9 9 8 8 7 7

203 158 ll8 95 66 64 54 45 32 30 26 22 19 17 15 15 14 13 12

IO

243 189 141 ll4 79 77 65 55 39 36 31 27 23 20 18 18 17 16 14 13 13 12

9 9

10

0.469 0.532 0.616 0.685 0.821 0.834 0.910 0.990 l.l 75 I .220 l.310 1.410 1.558 1.720 1.912 1.953 2.099 2.239 2.433 2.661 2.769 2.988 3.010 3.273

T HI-I N

14 12 10 8 6 4 3 2 l

1/ 0 2/ 0 3/ 0 4/ 0 250 300 350 400 500 600 700 750 800 900 1000

70-810

12 9 7 5 4 4 3 3 2 2 1 1 1

1 0 0 0 0 0 0 0 0

26 20 15 12 9 8 7 6 4 4 3 3 2 2 2 2 1 l l l

1 1

IO

11

9 8 8 7 7 6 6 5 5 5 4

10 9 9 8 8 7 6 6 6 5 5

ll

10

11

NATIONAL ELECTRICAL CODE

2020 Edition

Annex C: Tables

INFORMATIVE ANNEX C

Table C.17 Number of Type TC Cables Permitted in Cable Tray (4C MulticonductorTC Cable Assembly) (Based on fill in accordance with 392.22, Table 392.22(A), column 1, ampacity in accordance with 392.80) Conductor Insulation Type

Conductor Size (AWG/ kcmil)

Ventilated Tray Width [mm (in.)] 50 (2)

100 (4)

150 (6)

200 (8)

225 (9)

300 (12)

400 (16)

450 (18)

500 (20)

600 (24)

750 (30)

900 (36)

Cable Diameter

11

24 18 14 11 7 6 5 4 3 3 3 2 2 2 l

37 28 2J 17 12 10 8 7 5 5 4 3 3 3 2 2 2 2 2 2

48 37 27 22 15 12 11 9 7 6 5 4 4 4 3 3 3 3 2 2 2 2 2 l

56 43 32 25 17 15 12 JO 8 7 6 5 5 4 4 4 3 3 3 3 2 2 2 2

74 57 42 33 23 J9 16 J4 10 10 8 7 6 6 5 5 5 4 4 4 3 3 3 2

95 73 54 43 30 25 21 J8 13 12 JO 9 9 8 7 7 6 6 5 5 5

111 85 63 50 35 29 25 21 15 ]4 12 JO

122 93 69 55 38 32 27 23 17 16 13

148 114 84 67 46 39 33 28 21 19 16 14 13 12 Jl 11

186 142 105 84 58 48 41 34 26 24 20 17 17 15 14 13 12

223 171 127 100 69 58 49 41 31 29 24 21 20 18 17 16 15 14 13 12 ll lO 9 8

0.49 0.56 0.65 0.73 0.88 0.96 1.041 1.137 ] .315 l.365 l.49 1.598 1.75 1.91 2.ll 2.1 6 2.35 2.52 2.7J 2.91 3.02 3.33 3.69 4.02

TI-IHN

14 12 lO

8 6 4 3 2 1 1/ 0 2/ 0 3/ 0 4/ 0 250 300 350 400 500 600 700 750 800 900 1000

2020 Edition

8 6 5 3 3 2 2 l 1 2 l 0 0 0 0 0 0 0 0 0 0

NATIONAL ELECTRICAL CODE

l

1 1 I 1 0

]

4

4 3

lO

9 8 8 7 7 6 6 5 5 4 4

11 ll

IO 9

9 8 7 7 6 6 6 5 4

lO

9 8 8 7 7 6 5

ll

11 10 9 9 8 7

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Annex C: Tables

INFORMATIVE ANNEX C

Table C.18 Nwnber of Single Conductor Cables Permitted in Cable Tray (Based on fill in accordance with 392.22, Table 392.22(A), column 1, ampacity in accordance with 392.80) Conductor Insulation Type

Conductor Size (AWG/kcmil)

Ventilated Tray Width [mm (in.)] 50 (2)

100 (4)

4 3 3 3 5 4 4 3 3 2 2 2

8 7 6 6 IO 9 8 7 6 4 4 4 3 3 3

150 (6)

200 (8)

225 (9)

300 (12)

400 (16)

450 (18)

500 (20)

600 (24)

750 (30)

900 (36)

Cable Diameter

I2

I6 I4 13 I2 2I 18 I6 I4 I2 9 8 8 7 6 6

I8 I6 I5 I4 23 20 18 I6 I3 IO 9 9 8 7 7

24 22 20 I8 32 27 24 2I 18 14 12 I2

32 29 26 24 42 37 32 29 24 19 17 16 15 13 12

36 33 30 27 48 4I 36 32 27 22 I9 I8 I7 15 13

40 37 33 30 53 46 40 36 30 24 2I 20 19 17 15

48 44 40 36 64 55 48 43 36 29 25 24 23 20 I8

6I 56 5I 46 8I 70 6I 55 45 37 32 30 29 26 22

74 67 6I 56 98 84 74 66 55 44 39 37 35 3I 27

0.486 0.532 0.584 0.642 0.7II 0.766 0.817 0.864 0.949 l.051 l.122 1.156 l.188 I.252 l.31

THI-IN

I/ 0 2/ 0 3/ 0 4/ 0 250 300 350 400 500 600 700 750 800 900 1000

70-812

ll

IO 9 I6 I3 12 IO 9 7 6 6 5 5 4

ll

IO 9

NATIONAL ELECTRICAL CODE

2020 Edition

Annex C: Tables

INFORMATIVE ANNEX C

Table C.19 Number of Single Conductor Cables Permitted in Cable Tray (Based on fill in accordance with 392.22, Table 392.22(A), column 1, ampacity in accordance with 392.80) Conductor Conductor Size Insulation (AWG/kcmil) Type

Ventilated Tray Width [mm (in.)] 50 (2)

100 (4)

150 (6)

200 (8)

225

4 3 3 3 5 4 4 3 3 2 2 2

8 7 6 6 10 9 8 7 6 4 4 4 3 3 3

12

16 14 13 12 21 18 16 14 12 9 8 8 7 6 6

18 17 15 12 24 20 18 16 13 10 9 9 8 7 7

(9)

300 (12)

400 (16)

450 (18)

500 (20)

600 (24)

750 (30)

900 (36)

Cable Diameter

24 22 20 18 32 28 24 22 18 14 12 12

32 29 27 24 43 37 33 29 24 19 17 16 15 13 12

36 33 30 27 49 42 37 33 27 22 19 18 17 15 13

40 37 33 30 54 47 41 36 30 24 21 20 19 17 15

49 44 40 37 65 56 49 44 36 29 25 24 23 20 18

62 56 51 47 83 71 62 56 46 37 32 30 29 26 22

74 68 62 56 98 85 75 67 55 44 39 37 35 31 27

0.482 0.528 0.58 0.638 0.705 0.76 0.811 0.858 0.943 1.053 1.124 1.158 l.l9 1.254 1.312

XHHW 1/ 0 2/ 0 3/ 0 4/ 0 250 300 350 400 500 600 700 750 800 900 1000

2020 Edition

l

NATIONAL ELECTRICAL CODE

11

10 9 16 14 12 11

9 7 6 6 5 5 4

11

10 9

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Annex C: Tables

INFORMATIVE ANNEX C

Table C.20 Nwnber of Single Conductor Cables Permitted in Cable Tray (Based on fill in accordance with 392.22, Table 392.22(A), column 1, ampacity in accordance with 392.80) Conductor Conductor Insulation Size (AWG/ kcmil) Type

Ventilated Tray Width [mm (in.)] 50 (2)

100 (4)

150 (6)

200 (8)

225

3 3 3 2 4 4 3 3 2 2

7 6 6 5 9 8 7 6 5 4 3 3 3 3 2

ll 10 9 8 13 12

14 13 12 ll 18 16 14 12 10 8 7 7 6 6 5

16 15 14 13 20 17 15 14 12 9 8 8 7 7 6

(9)

300 (12)

400 (16)

450 (18)

500 (20)

600 (24)

750 (30)

900 (36)

Cable Diameter

22 20 18 17 27 24 21 19 16 13

29 27 24 22 37 32 28 25 21 17 15 14 13 12

33 30 28 25 41 36 32 28 24 19 17 16 15 14 12

37 34 31 28 46 40 35 32 26 21 19 18 17 15 14

44 40 37 34 55 48 42 38 32 26 23 21 20 18 17

56 51 47 43 70 61 54 49 41 33 29 27 26 23 21

67 62 57 52 84 73 65 58 49 40 35 33 31 28 26

0.532 0.578 0.63 0.688 0.765 0.82 0.871 0.918 l.003 l.ll3 l.184 l.218 l. 25 l. 314 l. 372

RI-fW

1/ 0 2/0 3/0 4/0 250 300 350 400 500 600 700 750 800 900 1000

70-814

lO

9 8 6 5 5 5 4 4

]]

10 lO 9 8

ll

NATIONAL ELECTRICAL CODE

2020 Edition

INFORMATIVE ANNEX D

Annex D: Examples

Informative Annex D Examples 77iis informative annex is not a part of the requirements of this NFPA document but is included for informational pmposes only.

Minimum Size Feeder Required {see 220.40]

Selection of Conductors. In the following examples, the results are generally expressed in amperes (A) . To select conductor sizes, refer to the 0 through 2000 volt (V) ampacity tables of Article 310 and the rnles of 310.1 4 that pertain to these tables.

General Lighting Small Appliance Laundry

Voltage. For uniform application of Articles 210, 215, and 220, a nominal voltage of 120, 120/ 240, 240, and 208Y/ 120 V is used in calculating the ampere load on the conductor.

4,500 VA 3,000 VA l,500 VA Total

9,000 VA 3,000 VA 2,100 VA

Net Load

5,100 VA 8,000 VA 5,500 VA

3000 VA at 100% 9000 VA- 3000 VA = 6000 VA at 35% Range (see Table 220.55) Dryer Load (see Tobie 220.54)

Fractions of an Ampere. Except where the calculations result in a majo1-fraction of an ampere (0.5 or larger), such fractions are permitted to be dropped.

Net Calculated Load

Power Factor. Calculations in the following examples are ba5ed, for convenience, on the assumption that all loads have the same power factor (PF) .

Net Calculated Load for 120/ 240-V, 3-wire, single-phase service or feeder

18,600 VA

18,600 VA-:- 240 V = 78 A Ranges. For the calculation of the range loads in these examples, Column C of Table 220.55 has been used. For optional methods, see Columns A and B of Table 220.55. Except where the calculations result in a major fraction of a kilowatt (0.5 or larger), su ch fractions are permitted to be dropped. SI Units. For metri c conversions, 0 .093 m 2 = 1 ft2 and 0.3048 m = 1 ft.

Sections 230.42(B) and 230.79 require service conductors and disconnecting mea ns rated not less than 100 amperes. Calculation for Neutral for Feeder and Service Lighting and Small-App]jancc Load Range: 8000 VA at 70% (see 220.61 ) Dryer: 5500 VA at 70% (see 220.61)

Example Dl(a) One-Family Dwelling

5,100 VA 5,600 VA 3,850 VA Total

The dwelling has a floor area of 1500 ft2 , exclusive of an unfinished cellar not adaptable for future use, unfinished attic, and open porches. Appliances are a 12-kW range and a 5.5-HV, 240V dryer. Assume range and dryer kW ratings equivalent to kVA ratings in accordance with 220.54 and 220.55.

14,550 VA

Calculated Load for Neutral 14,550 VA-:- 240 V = 61 A

Example D 1 (b) One-Family Dwelling

Calculated Load (see 220.40) General Lighting Load 1500 ft2 at 3 VA/ ft2 = 4500 VA Minimum Number of Branch Circuits Required {see 210. ll (A)l General Lighting Load: 4500 VA-:- 120 V = 38 A This requires three 15-A, 2-wi.re or two 20-A, 2-wire circuits. Small-Appliance 210.11(C)(1)1

Load: Two

2-wise,

20-A circuits

{see

La undry Load: One 2-wire, 20-A circuit {see 210.11 (C)(2)]

Assume same conditions as Example No. Dl (a), plus addition of one 6-A, 230-V, room air-condition ing unit and one 12-A, 115-V, room air-conditioning unit,* one 8-A, 115-V, rated waste dispose1~ and one 10-A, 120-V, ra ted dishwasher. See Article 430 for general motors and Article 440, Part VII, for a irconditioning equipment. Motors h ave nameplate ratings of 115 V and 230 V for use on 120-V and 240-V nomina l voltage systems. *(For feeder neuu-al, use larger of the two appliances fo r unbalance .)

Baduoom Branch Circuit: One 2-wire, 20-A circu it (no additional load calculation is required for this c ircuit) {see 210.11 (C) (3)]

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NATIONAL ELECTRICAL CODE

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Annex D: Examples

INFORMATIVE ANNEX D

From Example Dl (a), feeder current is 78 A (3-wire, 240 V) . Line A

Neutral

Amperes from Example Dl (a) One 230-Vair conditioner One 115-Vair conditioner and l 20-V d ishwasher One ll5-V disposer 25% oflargest motor (see 430.24)

78 6 12

61

Total amperes per conductor

LineB

12

78 6 10

3

8 3

8 2

99

84

104

Feeder Neutral Load in Accordance with 220.61 1500 ft2 at 3 VA Three 20-A circuits at 1500 VA

4,500 VA 4,500VA Total

9,000 VA 3,000 VA 2,lOO VA

Subtotal

5,lOOVA 5,600 VA 3,500 VA l,200VA

Total

15,400 VA

3000 VA at 100% 9000 VA- 3000 VA= 6000 VA at 35% Range: 8 kVA at 70 % Clothes dryer: 5 kVA at 70 % Dishwasher

Therefore, the service would be rated 110 A.

Example D2(a) Optional Calculation for On~Family Dwelling, Heating Larger Than Air Conditioning (see 220.82) The dwelling has a floor area of 1500 ft2 , exclusive of an unfinished cellar not adaptable for future use, unfinished attic, and open porches. It has a 12-kW range, a 2.5-kW water heater, a 1.2-kW dishwasher, 9 kW of electric space heating installed in five rooms, a 5-kW clothes dryer, and a 6-A, 230-V, room airconditioning unit. Assume range, water heater, dishwasher, space heating, and clothes dryer kW ratings equivalent to kVA. Air Conditioner kVA Calculation 6 Ax 230 V c- 1000 = 1.38 kVA This 1.38 kVA [item 1 from 220.82(C)] is less than 40% of 9 kVA of separate ly controlled electric heat f item 6 from 220.82(C)], so the 1.38 kVA need not be included in the service calculation. General Load 1500 ft2 at 3 VA Two 20-A appliance outlet circuits at 1500 VA each Laundry circuit Range (at nameplate rating) Water heater Dishwasher Clothes dryer Total

4,500 VA 3,000VA l,500VA 12,000VA 2,500VA l,200VA 5,000 VA 29,700VA

Application of Demand Factor [see 220.82(B)] First 10 kVA of general load at 100% Remainde r of general load at 40% (19.7 kVA x 0.4)

10,000 VA 7,880VA

Total of general load 9 kVA of heat at 40% (9000 VA x 0.4) =

l7,880VA 3,600VA

Total

21,480 VA

Calculated Load for Neutral 15,400 VA-;- 240 V= 64 A

Example D2(h) Optional Calculation for One-Family Dwelling, Air Conditioning Larger Than Heating [see 220.82(A) and 220.82(C)J

The dwelling has a floor area of 1500 ft2, exclusive of a n unfinished cellar not adaptable for future use, unfin ished attic, and open porches. It has two 20-A small appliance circuits, one 20-A laundry circuit, two 4-kW wall-mounted ovens, one 5.1-kv\T counter-mounted cooking unit, a 4.5-kW water heate1·, a 1.2-kv\T dishwasher, a 5-kW combination clothes wa5her and dryer, six 7-A, 230-V room air-conditioning uni ts, and a 1.5-kW permanently installed batlu-oom space heater. Assume wall-mounted ovens, counter-mounted cooking unit, water heater, dishwasher, and combination clothes washer and dryer kW ratings equivalent to kVA. Air Conditioning kVA Calculation Total amperes= 6 units x 7 A= 42 A

42 Ax 240 V c- 1000 = 10.08 kVA (assume PF= 1.0) Load Included at 100% Air Conditioning: Included below {see item 1 in 220.82(C)] Space Heater: Omit {see i tem 5 in 220.82(C)] General Load 1500 ft2 at 3 VA Two 20-A small-appliance circuits at 1500 VA each Laundry circuit Two ovens One cooking unit Water heater Dishwasher Washer/ dryer

4,500 VA 3,000 VA l,500VA 8,000 VA 5,100 VA 4,500VA l ,200VA 5,000 VA Total general load

Calculated Load for Service Size 21.48 kVA = 21,480 VA

First lO kVA at 100% Remainder at 40% (22.8 kVA x 0.4 x 1000)

21,480VA c- 240 V = 90 A Therefore, the minimum service rating would be 100 A in accordance with 230.42 and 230.79.

70-816

32,800 VA 10,000 VA 9,120 VA

Subtotal general load

19,120 VA 10,080VA

Total

29,200 VA

Air conditioning

NATIONAL ELECTRICAL CODE

2020 Edition

INFORMATIVE ANNEX D

Annex D: Examples

Remainder of general load at 40% (23,200 VA x 0.4)

Calculated Load for Service

29,200 VA -c 240 V = 122 A (service rating) Feeder Neutral Load, in accordance with 220.61 Assume that the twu 4-kVA wall-mounted ovens are supplied by one branch circuit, the 5.1-kVA counte1·-m ou nted cooking unit by a separate circuit.

9,280 VA

Total net general load

19,280 VA

Heat Pump and Supplementary Heat'-' 240V x 24A = 5760VA 15 kW Electric Heat:

1500 ft2 at 3 VA Three 20-A circuits at 1500 VA

4,500VA 4,500 VA

5760 VA + (15,000 VA x 65%) = 5.76 kVA + 9.75 kVA = 15.51 kVA

Subtotal

9,000VA 3,000VA 2,lOOVA

*U supplementary heat is not on at same time as heat pump, heat pump kVA need not be added to total.

Subtotal

5,l OOVA

Totals Net general load Heat pump and supplementary heat

3000 VA at 100% 9000 VA- 3000 VA = 6000 VA at 35%

Two 4-kVA ovens plus one 5.1-kVA cooking unit = 13.1 kVA. Table 220.55 permits 55% demand factor or 13.1 kVA x 0.55 = 7.2 kVA feeder capacity.

19,280 VA 15,510 VA Total

34,790 VA

Calculated Load for Service

Subtotal from above Ovens and cooking tmit: 7200VA x 70% for neutral load Clo thes washer/dryer: 5 kVA x 70% for neutral load Dishwasher

5,100 VA 5,040VA

Total

14,840 VA

3,500VA l,200VA

Calculated Load for Neutral 14,840VA -c 240V = 62

Example D2(c) Optional Calculation for One-Family Dwelling with Heat Pump (Single-Phase, 240/ 120-Volt Service)

34.79kVAx 1000-c240V= 145A Therefore, this dwelling unit would be pennitted to be served by a 150-A service.

Example D3 Store Building A store 80 ft by 60 ft, or 4,800 ft2, ha~ 30 ft of show window. The1·e are a total of 80 duplex receptacles. The se1vice is 120/ 240 V, single phase 3-wire service. Actual connected lig hting load is 7,000 VA, a ll of which for this example is conside red continuous. All calculati ons are rounded up or down as permitted in 220.5(B) . Calculated Load (see 220. 40)

(see 220.82) The dwelling has a floo r area of 2000 ft2 , exclusive of an unfinished cellar not adaptable for future use, unfinished attic, and open porches. It has a 12-kW range, a 4.5-kW wate1· heate1-, a 1.2-kW dishwasher, a 5-kW clothes dryer, and a 2\1.l-ton (24-A) heat pump with 15 kW of backup heat. Heat Pump kVA Calculation 24 Ax 240 V -c 1000 = 5.76 kVA This 5 .76 kVA is less than 15 kVA of the backup heat; therefore, the h eat pump load need not be included in the service calculation [see 220.82(C)]. General Load

2000 ft2 at 3 VA Two 20-A appliance outlet circuits at 1500 VA each Laundry circuit Range (at nameplate rating) Water heater Dishwasher Clo thes dryer Subtotal general load First 10kVAat100%

6,000VA 3,000VA l,500VA 12,000VA 4,500VA l,200VA 5,000VA 33,200VA 10,000VA (contintws)

2020 Edition

NATIONAL ELECTRICAL CODE

Noncontinuous Loads Receptacle Load (see 220.44) 80 receptacles a t 180 VA 10,000 VA at 100% 14,400 VA-10,000 VA= 4,400 VA at 50%

14,400 VA 10,000 VA 2,200 VA Subtotal

Continuous Loads General Lighting* 4,800 ft2 at l .9 VA/ft2 Show Window Lighting Load 30 ft at 200 VA/ft [see 220.14(G)} Outside Sign Cirettit [see 220.14(F)}

12,200 VA

9,120 VA 6,000 VA l ,200 VA

Subtotal Subtotal from noncontinuous

16,320 VA 12,200 VA

Total noncontinuous loads + continuo us loads=

28,520 VA

*In the example, the acn1al connected lig hting load a t 125% (7,000 VA x 1.25 VA) is less than the load from Table 220.12, so the required minimum lighting load from Ta ble 220.12 is used in the calculation . Had the acnial lighting load x 125% been greater than the value calculated from Table 220.1 2, the acnial connected lighting load would have bee n used.

70-817

Annex D: Examples

INFORMATIVE ANNEX D

Minimum Number of Branch Circuits Required General Lighting: Branch circuits need only be installed to supply the actual connected load [see 210.11 (B )].

Example D3(a) Industrial Feeders in a Common Raceway

7,000 VA x 1.25 = 8,750 VA 8,750 VA -c 240 V = 36.45 A fo1- 3-wire, 120/ 240 V 8,750 VA -c 120 V = 72.92 A The lighting load would be permitted to be served by 2-wire or ~wi re, 15- or 20-A circuits with combined capacity equal to 36 A or greater for 3-wire circuits or 73 A or greater for 2-wire circuits. The feeder capacity a5 we ll as the number of branchcircuit positions available for lighting circuits in the panelboard must reflect the full calculated load of 9,120 VA. Lighting loads from Table 220.1 2 already include 125% for continuous load. See note at bottom of Table 220.1 2. Show Window 6,000VAx l.25=7,500VA 7,500 VA -c 240 V = 31.25 A fo1- 3-wire, 120/ 240 V 7,500 VA 7 120 V = 62.5 A for 2-wire, 120 V The show window lighting is permitted to be served by 2-wire or ~wire circuits with a capacity equal to 31 A or greater for 3wire circuits or 63 A or greater for 2-wire circuits. Receptacles required by 210.62 are assumed to be included in the receptacle load above if these receptacles do not supply the show window lighting load. Receptacles Receptacle Load: 14,400VA 7 240V = 60A for

An industrial multi-building facility has its service at the rear of its main building, and then provides 480Y/ 277-volt feeders to additional buildings behind the main building in o rder to segregate certain processes. The facility supplies its remote buildings through a partially enclosed access corridor that extends from the main switchboard 1-eanvard a long a path that provides conven ien t access to services within 15 m (50 ft) of each additional building supplied. Two building feeders share a common raceway for approximately 45 m (150 ft) and run in the access corridor along wi th process steam and conu-ol and communications cabling. The steam raises the ambient temperattu-e around the power raceway to as much as 35°C. At a tee fitting, the individual building feeders then run to each of d1e two buildings involved. The feeder neutrals are not connected to the equipment grounding conducto1-s in the remote buildings. All disu-ibution equipment ter minations a re listed as being suitable for 75°C connections . Each of the two buildings has the following loads: Lighting, 11,600 VA, comprised of electric-discharge luminaires connected at 277 V Receptacles, 22 125-volt, 20-ampere receptacles on generalpurpose branch circuits, supp lied by separate ly derived systems in each of the buildings 1 Air comp1-essor, 460 volt, three phase, 5 hp 1 Grinder, 460 volt, three phase, 1.5 hp

~wire,

3 Welders, AC transformer type (nameplate: 23 amperes, 480 volts, 60 percent duty cycle)

120/ 240V

14,400 VA 7 120 V = 120 A for 3-wire, 120/ 240 V The receptacle load would be permitted to be se1-ved by 2wire or ~wire circuits with a capacity equal to 60 A or greater for ~wire circuits or 120 A or greater for 2-wire circuits. Minimum Size Feeder (or Service) Overcurrent Protection (see 215.3 or 230.90) Subtotal noncontinuous loads Subtotal continuo us loads not from Table 220.12 at 125% (7,200 VA x l.25) (sign and show \\fodow) Subto tal of calculated con tinuous loads with 125% already included Total

12,200 VA 9,000 VA

3 lndusu-ial Process Dryers, 480 volt, three phase, 15 kW each (assume continuous use throughout certain shifts) Determine the overcurrent protection and conductor size for the feeders in the common raceway, assum ing the use of XHHW-2 insulation (90°C): Calculated Load !Note: Fo1- reasonable p1-ecision, volt-ampere calculations are carried to three sig nificant figures only; where loads are converted to amperes, the results are rounded to the nearest ampere [see 220.5(B)]f.

9,120VA 30,320 VA

30,320VA -c 240V = 126A The next higher standard size is 150 A (see 240.6). Minimum Size Feeders (or Service Conductors) Required [see 215.2, 230.42(A)]

For 120/ 240 V, ~wire system, 30,320 VA 7 240 V = 126 A Service or feeder conductor is AV•/ G Cu in accordance with 215.3 and Table 310.16 (with 75°C te1-minations) .

Noncontinuous Loads Receptacle Load (see 220.44) 22 receptacles at 180 VA Welder Load [see 630.ll(A),

3,960 VA

Table 630.l l(A)}

Each welder: 480V x 23A x 0.78 = 8,610 VA All 3 welders [see 630.ll(B)} (demand factors 100%, 100%, 85% respectively) 8,610 VA+ 8,610 VA+ 7,320 VA =

24,500 VA

Subtotal, Noncontinuous Loads

28,500VA

Motor Loads (see 430.24, Tabl.e 430.250) (continues)

70-818

NATIONAL ELECTRICAL CODE

2020 Edi tion

INFORMATIVE ANNEX D Air compressor: 7.6 Ax 480 V x v3 = Grinder: 3 A x 480 V x v3 = Largest motor, additional 25%:

6,310 VA 2,490 VA l,580VA

Subtotal, Motor Loads 10,400 VA By using 430.24, the motor loads and the noncontinuous loads can be combined for the remaining calculation. Subtotal for load calculations, Noncontinuous Loads 38,900 VA Continuous Loads General Lighting ll, 600VA 15 kW each 3 Industrial Process Dryers 45,000VA Subtotal, Continuous Loads:

56,600VA

Overcurrent protection (see 215.3) The overcurrent protective device must accommodate 125% of the continuous load, plus the noncontinuous load:

Annex D: Examples

ity corridor were at normal temperatures f (30°C (86°F)], and if the lighting at each building were supplied from the local separately derived system (thus requiring no neutrals in the supply feeders), the raceway result (95,500 VA 7 0.8 = 119,000 VA; 119,000 VA.;. (480 V x v3) = 143 A, or a 1 AWG conductor@ 90°C) could not be used, because the termination result (1/0 AWG) based on the 75°C column of Table 310.1 6 would become the worst case, requiring the larger conductor. In every case, the overcurrent protective device shall provide overcurrent protection for the feeder conductors in accordance with their ampacity as provided by this Code (see 240.4). A 90°C 2/ 0 AWG conductor has a Table 310.16 ampacity of 195 amperes. Adjusting for the conditions of use (35°C ambient temperature, 8 cm-rent-carrying conductors in the common race\vay), 195 Ax 0.96 x 0.7 = 131 A

Continuous load Noncontinuous load

56,600 VA 38,900VA

Subtotal, actual load [actual load in amperes] (99,000 VA.;. (480V x v3) = II9 A] (25% of 56,600 VA) (See 215.3)

95,500VA

The 150-ampere circuit breaker protects the 2/ 0 AWG feeder conductors, because 240.4(B) permits the use of the next higher standard size overcurrent protective device. Note that the feeder layout precludes the application of 310.14(A) (2) Exception.

14,200VA

Feeder Neutral Conductor (see 220. 61)

109,700 VA Total VA Conversion to amperes using three signjficant figures: 109,700 VA I (480V x ./3) = 132 A Minimum size overcurrent protective de\~ce: 132 A Minimum standard size ovcrcu1Tent protective device (see 240.6j. 150 amperes

Where the overcurrent protective device and its assembly are listed for operation at 100 percent of its rating, a 125 ampe1·e overcurrent protective device would be permitted. However, overcurrent protective device assemblies listed for 100 percent of their rating are typically not available at the 12.'.rampere rating. (See 215.3 Exception.) Ungrounded Feeder Conductors The conductors must independently meet requirements fm (1) terminations, and (2) conditions of use throughout the raceway run.

Minimum size conductor at the overcurrent device termination [see 110.14(C) and 215.2(A)(l), using 75°C ampacity column in Table310.16}: l / OAWG. Minimum size conducto1·s in the raceway based on actual load [see Article 100, Ampacity, and 310.15(C)(l) and correction Jactflrs lo Table 310.16}: 95,500 VA.;. 0.7.;. 0.96 = 142,000 VA [70% = 310.l5(C) (l)] & (0.96 =Correction factors to Table 310.16] Conversion to amperes: 142,000 VA.;. (480Vx./3)= 171 A Note that the neutral conductors are counted as currentcarrying conductors [see 310.15(£)(3)} in this example because the discharge lighting has substantial nonlinear content. This requires a 2/ 0 AWG conductor based on the 90°C column of Table 310.1 6. Therefore, the worst case is g iven by the race\vay conditions, and 2/ 0 AWG conductors must b e used. If the util-

2020 Edition

NATIONAL ELECTRICAL CODE

Because 210.11 (B) does not apply to these buildings, the load cannot be assumed to be even ly disa-ibuted across phases. Therefore the maxjmum imbalance must be assumed to be the full lighting load in this case, or 11,600 VA. (11,600 VA 7 277 V = 42 A.) The ability of the neua-al-to-return fault current [see 250.32(B) Exception No. 2} is not a factor in this calculation. Because the neutral mns between the main switchboa1-d and the building panelboard, likely terminating on a busbar at both locations, and not on overcurrent devices, the effect5 of continuous loading can be disregarded in evaluating i ts terminations {see 215.2(A)(1) Exception No. 2). That calculation is (11,600 VA .;. 277 V = 42 A), to be evaluated under the 75°C column of Table 310.16. The minimum size of the neutral might seem to be 8 AWG, but that size would n ot be sufficient to be depended upon in the event of a line-to-neua-al fault [see 215.2(A)(2), second paragraph]. Therefore, because the minimum size equipment grounding conductor for a 150 ampere circuit wired with 2/ 0 AWG conductors, as covered in Table 250.1 22, is 6 AWG, that is the minimum neua-al size required for this feeder.

Example D4(a) Multifamily Dwelling A multifamily dwelling has 40 dwelling units. Meters are in two banks of 20 each with indi,~dual feeders to each dwelling unit. One-half of d1e dwelling units are equipped with electric ranges not exceeding 12 kW each. Assume range kv\T rati ng equivalent to kVA rating in accordance wid1 220 .55. Other half of ranges are gas ranges. Area of each dwelling unit is 840 ft2. Laundry facilities on prem ises are available to all tenants. Add no circuit to individual dwelling unit. Calculated Load for Each Dwelling Unit (see Article 220) General Lighting: 840 ft2 at 3 VA/ ft2 = 2520 VA Special Appliance: Elecu-ic range (see 220.55) = 8000 VA

70-819

Annex D: Examples

INFORMATIVE ANNEX D

Minimum Number of Branch Circuits Requll-ed for Each DwellingUnit [see210.ll(A)} General Lighting Load: 2520 VA 7 120 V = 21 A or two 15-A, 2wire circuits; or two 20-A, 2-wire circuits Small-Appliance Load: Two 2-wire circuits of 12 AWG wire [see 210.ll(C)(l)J Range Circuit: 8000 VA 7 240 V = 33 A or a circuit of two 8 AWG conductors and one 10 AWG conductor in accordance with 210.19(A)(3) Minimum Size Feeder Required for Each Dwelling Unit (see 215.2)

Net calculated load for 120/ 240-V, 3-wire system, 65,590 VA -o- 240 V = 273 A Feeder Neutral

Lighting and Small-Appliance Load Range Load: 25,000 VA at 70% [see 220.61(B)] Calculated Load (neutral)

40,590 VA 17,500VA 58,090VA

Calculated Load for Neutral

58,090 VA -o- 240 V = 242 A Calculated Load (see Artic/.e 220): General Lighting Small Appliance (two 20-ampere circuits) Su b to tal Calcula ted Load (without ranges)

2,520 VA 3,000 VA

Further Demand Factor [220. 6 I (B )]

5,520 VA

200 A at 100% 242 A - 200 A= 42 A at 70% Net Calculated Load (neutral)

Application of Demand Factor (see Table 220. 42)

First 3000 VA a t 100% 5520 VA - 3000 VA= 2520 VA at 35% Net Calculated Load (without ranges) Range Load Net Calculated Load (with ranges)

200A 29A

3,000VA 882VA 3,882VA 8,000VA ll,882VA

Size of Each Feeder (see 215.2) For 120/ 240-V, 3-wire system (without ranges) Net calculated load of 3882 VA 7 240 V = 16 A For 120/240-V, 3-wire system (with ranges) Net calculated load, 11,882 VA 7 240 V = 50 A

229 A

Minimum Size Main Feeders (or Service Conductors) Required (Less House Load) (For 40 Dwelling Units - 20 with Ranges)

Total Calculated Load: Lighting and Small-Appliance Load 40 unitS x 5520 V

220,800 VA

Application of Demand Factor (from Table 220.42)

D.8.6 Feeder Neutral

First 3000 VA at 100% Next 120,000 VA - 3000 VA= 117,000 VA at 35% Remainder 220,800 VA- 120,000 VA= 100,800 VA at25%

3,000 VA 40,950 VA 25,200 VA

3,882 VA 5,600VA

Net Calculated Load Range Load: 20 ranges (less than 12 kVA) (see Col. C, Table 220.55)

69,150VA

Lighting and Small-Appliance Load Range Load: 8000 VA at 70% (see 220.61) (only for apartments \\~th electric range) Net Calculated Load (neutral)

5,600VA 9,482VA

Net Calculated Load

104,150VA

Calculated Load for Neutral

Feeder Neutral

Minimum Size Feeders Required from Service Equipment to Meter Bank (For 20 Dwelling Units - 10 with Ranges)

Lighting and Small-Appliance Load Range: 35,000 VA at 70% [see 220.61(B)] Calcula ted Load (neutral)

110,400VA

Application of Demand Factor First 3000 VA at 100% 11 0,400 VA - 3000 VA= 107 ,400 VA at 35%

3,000 VA 37,590 VA

Net Calculated Load Range Load: 10 ranges (not over 12 kVA) (see Col C,

40,590 VA 25,000 VA

Table 220.55,25 kW)

Net Calculated Load (with ranges)

For 120/ 240-V, 3-wire system Net calculated load of104,150 VA 7 240 V = 434 A

9482 VA -o- 240 V= 39.5 A

Total Calculated Load: Lighti ng and Small Appliance 20 units x 5520 V

35,000 VA

69,150 VA 24,500 VA 93 ,650 VA

93,650 VA -o- 240 V = 390 A Further Demand Factor [see 220.61(B)J

200 A at 100% 390 A - 200 A= 190 A at 70% Net Calculated Load (neutral)

200A 133A 333A

65,590 VA [See Table 3 10.16 through Table 310.21, and 310.15(B), (C), and (E).}

70-820

NATIONAL ELECTRICAL CODE

2020 Edi tion

INFORMATIVE ANNEX D

Example D4(b) Optional Calculation for Multifamily

Dwelling

Annex D: Examples

Range Space Heating (see 220.51) Water H eater Net Calculated Load (for individ ual dwelling unit)

A multifamily dwelling equipped with elecu-ic cooking and space heating or a ir conditioning has 40 dwelling unit~. Meters are in two banks of 20 each plus h o use metering and ind ividual feeders to each dwelling unit. Each dwel.ling unit is equipped with an elecu-ic range of 8kW nameplate rating, four 1.5-kW separately controlled 240-V electric space heaters, and a 2.5-kW, 240-V elecu·ic water heater. Assume range, space heater, and water heater k',Y ratings equiva lent to kVA. Calculate the load for the individual dwelling unit b y the standard calculation (Part III of Article 220) .

6,400 VA 6,000 VA 2,500 VA 18 ,782 VA

Size of Each Feeder

For 120/ 240-V, 3-wire system, Net calculated load of 18,782 VA-;- 240 V = 78 A Feeder Neutral (see 220.61)

Lighting and Small Appliance Range Load: 6400 VA at 70 % [see 220.61(B)] Space and Water Heating (no neutral): 240 V Net Calcula ted Load (neutral)

A common laundry facility is available to a ll tenants [see 210.52(F), Exception No. 1].

3,882 VA 4,480 VA OVA 8 ,362 VA

Calculated Load for Neutral

Area of each dwelling unit is 840 ft2 .

8362 VA-;- 240 V = 35 A Calculated Load for Each Dwelling Unit (see Part JI and P(trt Ill of Article 220)

General Lighting Load: 840 ft2 at 3 VA/fr2 Electric range Electric heat: 6 kVA (or air conditioning if larger)

2,520VA 8,000 VA 6,000VA

Electr ic water heater

2,500VA

Minimwn Number of Branch Circuits Required for Each Dwelling Unit

General Lighting Load: 2520 VA-;- 120 V = 21 A or two 15-A, 2wire circuits, or two 20-A, 2-wire circuits Small-Appliance Load: Two 2-wire c ircui ts of 12 AV•l G [see 210.ll(C)(l)J Range Circuit (See Table 220.55, Column B ): 8000 VA x 80%-;- 240 V = 27 A on a circuit of three 10 AWG conductors in accordance with 210.19(A)(3) Space Heating: 6000 VA-;- 240 V = 25 A Number of circuits (see 210.11) Minimwn Size Feeder Required for Each Dwelling Unit 215.2)

Calcu lated Load (see Articl.e 220): General Lighting Small Appliance (two 20-A circuits) Su btotal Calcula ted Load (without range and space heating)

(see

Net Calculated Load (witho ut range and space heating)

5,520 VA

NATIONAL ELECTRICAL CODE

Net Calculated Load (20 dwelli ng u ni t~) Net Calculated Load Using Optional Calculation

110,400 VA 170,000 VA 160,000 VA 440 ,400 VA

(see Table 220.84)

440,400 VA x 0.38

167,352 VA

167,352 VA-;- 240 V = 697 A Minimum Size Main Feeder Required (Less House Load) (For 40 Dwelling Units)

Calculated Load: Lighting and Small-Appliance Load 40 units x 5520 V Water and Space Heating Load 40 units x 8500 V Range: 40 ranges x 8000 V

220 ,800 VA 340,000 VA 320,000 VA 880,800 VA

Net Calculated Load Using Optional Calculatio n (see Table 220.84) 880,800 VA x 0.28 = 246,624 VA 246,624 VA.;. 240 V = 1028 A

3,000VA 882VA 3,882VA (continues)

2020 Edition

Total Calculated Load: Lighting and Small-Appliance Load 20 units x 5520 V Water and Space Heating Load 20 units x 8500 V Range Load: 20 x 8000 V

Net Calculated Load (40 dwelli ng units) 2,520VA 3,000VA

Application of D emand Factor

First 3000 VA a t 100% 5520 VA - 3000 VA= 2520 VA at 35%

Minimum Size Feeder Required from Service Equipment to Meter Bank (For 20 Dwelling Units)

Feeder Neutral Load for Feeder from Service Equipment to Meter Bank (For 20 Dwelling Units)

Lighting and Small-Appliance Load 20 units x 5520 V

ll0,400 VA (continues)

70-821

Annex D: Examples

INFORMATIVE ANNEX D 3,000VA 37,590VA

First 3000 VA a t 100% 110,400 VA- 3000 VA= 107,400 VA at 35% Net Calculated Load

40,590VA 24,500VA

20 ranges: 35,000 VA at 70% [see Table 220.55 and 220.6J(B)]

Total

65,090 VA

Net calculated load of3882VA 7 2 legs Fo1-

120 /20~V,

7

120 V/ leg = 16 A

3-wire system (with ranges),

Net calculated load (range) of 8000 VA 7 208 V = 39 A Total load (range + lighting)= 39 A+ 16 A= 55 A Reducing the netmal load on the feeder to each dwelling unit is not permitted [see 220.61(C)(l)]. Minimum Size Feeders Required from Service Equipment to Meter Bank (For 20 Dwelling Units - 10 with Ranges)

65,090 VA-;- 240 V = 271 A Further Demand Factor [see 220.61(B)]

For 208Y/ 120-V, 3-phase, 4-wire system,

First 200 A at l 00% Balance: 271A-200 A= 71Aat 70% Total

Ranges: Maximum number bet\'/een any t\vo pha~e legs= 4

200A 50A

2 x 4 = 8.

250A

Ta ble 220.55 demand= 23,000 VA Per phase demand= 23,000 VA 7 2 = 11,500 VA

Feeder Neutral Load of Main Feeder (Less House Load) (For 40 Dwelling Units)

Equivalent 3-phase load= 34,500 VA Net Calculated Load (tota l):

Lighting and Small-Appliance Load 40 units x 5520 V First 3000 VA a t 100% Next 120,000VA- 3000 VA= 117,000VAat 35% Remainder 220,800 VA - 120,000 VA= 100,800 VA a t 25%

220,800VA 3,000YA 40,950VA 25,200 VA

Net Calculated Load

69,150 YA 38,500VA

40 ranges: 55,000 VA at 70% [see Table 220.55 and 220.6J(B)]

Total

107,650 VA

40,590 VA+ 34,500 VA = 75,090 VA 75,090 VA-;- (208 V) (1.732) = 208 A Feeder Neutral Size

Net Calculated Lighting and Appliance Load & Equivalent Range Load: 40,590 VA+ (34,500 VA at 70%) = 64,700 VA Net Calculated Neutral Load: 64,700 VA-;- (208 V) (1.732) = 180 A

107,650 VA-;- 240 V = 449 A

Minimum Size Main Feeder (Less House Load) (For 40 Dwelling Units - 20 with Ranges)

Further Demand Factor [see 220.61(B)]

For 208Y/120-V, 3-phase, 4-wire system, First 200 A at 100% Balance: 449 - 200 A= 249 A a t 70% Total

200A l 74A

Ranges:

374A

Maximum number beMeen any t\vo phase legs = 7 2 x 7 = 14.

Example D5(a) Multifamily Dwelling Served at 208Y/ 120 Volts, Three Phase

Ta ble 220.55 demand = 29,000 VA Per phase demand= 29,000 VA 7 2 = 14,500 VA Equivalent 3-phase load= 43,500 VA

All conditions and calculations are the same as for the multifamily dwelling [Example D4(a)] se1ved at 120/ 240 V, single phase except as fo llows: Service to each dwelling unit would be two phase legs and neutral. Minimum Number of Branch Circuits Required for Each DwellingUnit (see210.11) Range Circuit: 8000 VA -;- 208 V = 38 A or a circuit of t\vo 8 AWG conductors and one 10 AWG conductor in accordance with 210.1 9(A)(3)

Net Calculated Load (total): 69,150 VA+ 43,500 VA = 11 2,650 VA 11 2,650 VA-;- (208 V) (1.732) = 313 A Main Feeder Neutral Size: 69,150 VA+ (43,500 VA at 70%) = 99,600 VA 99,600 VA-;- (208 V) (1.732) = 277 A Further Demand Factor (see 220.61)

Minimum Size Feeder Required for Each Dwelling Unit (see 215.2)

For 120/ 208-V, 3-wire system (with ou t ranges),

200 A at 100% 277 A - 200 A= 77 A at 70% Net Calculated Load (neutral)

70-822

NATIONAL ELECTRICAL CODE

200.0 A 54A 254A

2020 Edi tion

INFORMATIVE ANNEX D

Minimum Size Service Required (Less House Load) (for 40 Dwelling Units) (Assume Balanced Load)

Example D5(b) Optional Calculation for Multifamily Dwelling Served at 208YI 120 Volts, Three Phase

Net Calculated Load:

All conditions and calculations are the same as for Optional Calculation for the Multifamily Dwelling [Exa mple D4(b )] served at 120/240 V, single phase except as follows: Service to each dwelling unit would be two phase legs and neutral. Minimum Number of Branch Circuits Required for Each Dwe lling Unit (see 210.11)

Range C ircuit (see Tabl,e 220.55, Column B): 8000 VA at 80%.;208 V = 31 A or a circuit of two 8 AWG conductors and one 10 AWG conductor in accordance wid1 210.1 9(A) (3) Space Heating: 6000 VA 7 208 V = 29 A Two

2~ampere,

2-pole circuits required, 12 AWG conductors

Minimwn Size Feeder Required for Each Dwelling Unit

=

90 A

Feeder Neutral Load for Feeder from Service Equipment to Meter Bank (for 40 Dwelling Units) Lighting and Small-Appliance Load

40 units x 5520 VA= 220,800 VA First 3000 VA at 100% = 3000 VA Next 120,000 VA - 3000 VA = 117 ,000 VA 11 7,000 VA at 35% = 40,950 VA Rema inder 220,800 VA - 120,000 VA= 100,800 VA at 25% 25,200 VA

=

Net Calculated Load: 69,1 50 VA

2xl4=28

Line to lin e =14,900 VA.;- 208 V = 71.6 A

Ta ble 220.55 demand 43,000 VA per phase

Total load= 16.2 A + 71.6 A= 88 A Minimwn Size Feeder Required for Service Equipment to Meter Bank (for 20 Dwelling Units) Net Calculated Load

=

15,000 VA + (1000 VA x 28)

Demand = 43,000 VA.;- 2 = 21,500 VA Equivale nt 3-phase load= 21,500 VA x 3 = 64,500 VA Neutral Load = 64,500 VA at 70% [See Table 220 .55 and 220.61 (B) l Neutral Load= 45,1 50 VA

465 A

Feeder Neutral

Net Calculated Neutral Load (tota l) : 69,150 VA+ 45,150 VA

Load for Feeder from Service Equipment to Meter Bank (for 20 Dwelling Units) Lighting and Small-Appliance Load

20 units x 5520 VA 3000VA

685 A

Maximum number b etween any two phase legs= 14

3882 VA 7 2 legs 7 120 V per leg= 16.2 A

=

=

Ranges:

Net calculated load (lighting line to neutral):

167,352 VA.;- (208 V) (1.732)

246,624 VA.;- (208 V) (1.732)

Minimum Size Main Feeder (Less House Load) (for 40 Dwelling Units - 40 with Ranges) for 208Y/ 120-V, 3-Phase, 4-Wire System

120/ 208-V, 3-wire circuit Net calculated load of 18,782 VA 7 208 V

Annex D: Examples

=

114,300 VA.;- (208 V) (1.732) = 317 A Further Demand Factor [see 220.61(B)]

110,400 VA first 3000 VA at 100%

110,400 VA- 3000 VA= 107,400 VA at 35%

= 114,300 VA

=

=

37,590 VA

Net Calculated Load: 40,590 VA Minimum Size Main Feeder (Less House Load) (for 20 Dwelling Units- 20 Ranges) for 208Y/ 120-V, 3-Phase, 4-Wrre System

200 A at 100% 317 A - 200 A= II7 Aat 70% Ne t Calcu lated Load (neutral)

200A 82A 282 A

Example D6 Maximum Demand for Range Loads

Ranges: Maximum numbe1- benveen any two phase legs = 7 2 x 7 =14 Tabl e 220.55 demand= 29,000 VA

=

Table 220.55, Column C, applies to ranges not over 12 kW. The application of Note 1 to ranges over 12 kW (and not over 27 kW) and Note 2 to ranges ove1- 81'.; kW (and not over 27 kW) is illustrated in the following two examples.

Per phase demand= 29,000 VA .;- 2 = 14,500 VA

A. Ranges AU the Same Rating(see Table 220.55, Note 1)

Equivalent 3-phase load = 43,500 VA

Assume 24 ranges, each rated 16 kW.

Net Calculated Neuu·al Load (total): 40,590 VA+ 43,500 VA 84,090 VA 84,090 VA.;- (208 V) (1.732)

2020 Edition

=

234 A

NATIONAL ELECTRICAL CODE

From Table 220.55, Column C, the maximum demand for 24 ranges of 12-kW rating is 39 kW. 16 kW exceeds 12 kW by 4. 5% x 4 = 20% (5% increase for each kW in excess of 12)

70-823

Annex D: Examples

INFORMATIVE ANNEX D

39 kW x 20% = 7.8 kW increase 39 + 7.8 = 46 .8 kW (value to be used in selection offeeders) B. Ranges of Unequal Rating(see Table 220.55, Note 2)

If no temperature correction or ampacity adjustment factors are requit-ed, the following table includes conductor sizes calculated using the requirement5 in 310.1 2. This table is based on 75°C terminations and without any adjustment or correction factors.

Assume 5 ranges, each rated 11 kW; 2 ranges, each rated 12 kW; 20 ranges, each rated 13.5 kW; 3 ranges, each rated 18 kW.

Conductor (AWG or kcmil) Aluminum or

5 ranges 2 ranges 20 ranges 3 ranges

x

12 kW =

x 12 kW= x13.5kW = x 18 kW=

30 ranges, Total kW =

60 kW (use 12 kW for range rated less than 12) 24 kW 270 k\N 54 kW 408kW

408 -;- 30 ranges = 13.6 kW (average to be used fen- calcula· tion) From Tabl e 220.55, Column C, the demand for 30 ranges of 12-kW rating is 15 k\ 12 in.)

'I

!;~~

685 mm- 2030 mm (27 in.- 80 in.)

~305

(~12

mm in.)

+-------:_ _...._ _.

I

~685

mm

k

(a)

FIGURE J.3 70-842

X> 305 mm (> 12 in.)

(~?in .)

l r

510 mm-:>635 mm (>20 in.- :>25 in.)

~I

~I

~~t;;::---.:;;1120 mm

:>1220 mm

--iiilllllililillllllli•-(-$4--+8in.)

...................

{a)

FIGURE J.4

('4r)

{b)

Vertical Clearance. FIGURE J.6.2

Obstructed High Forward Reach.

J.7 Side Reach.

J.5 Required Clear Width. Protruding objects shall not reduce the clear width required for accessible routes.

J.6

Forward Reach.

J.6.1 Unobstructed. v\The1·e a fonvard reach is unobstructed, the high fonvard reach shall be 1220 mm (48 in. ) maximum, and the low forward reach shall b e 380 mm (1 5 in. ) minimum a bove the fini sh floor or ground. (Se,e Figure]6.1.) J .6.2 Obstructed High Reach. Where a high fonvard re ach is over an obstruction, the clear floor space shall extend beneath the element for a distance not less than the required reach depth over the obsffuction . The hig h fonvard reach shall be 1220 mm (48 in.) maximum where the reach depth is 510 mm (20 in. ) maximum. Where the reach depth exceeds 510 mm (20 in. ), the hig h forward reach shall be 1120 mm (44 in.) maximum, and the reach depth shall be 635 mm (25 in. ) maximum. (SeeFigure]6.2.)

J.7.1 Unobstructed. Where a clear floo1· or ground space allows a parallel approach to an ele ment, and the side reach is unobstructed, the high side reach sha ll be 1220 mm (48 in. ) maximum, and th e low side reach sha ll be 380 mm (15 in.) minimum above the fin ish floor or ground. (See Figure] 7.1. ) Exception No. 1: An obstruction shall be permitted between the clear floor or ground space and the element where the depth of the obstruction is 255 mm ( 10 in.) maximum. Exception No. 2: Operable parts of jitel dispensers shall be permitted to be 1370 mm (54 in.) maximum, rneasured from the swface of the vehicular way where fuel dispensers are installed on e>.isting curbs.

J.7.2 Obstructed High Reach. Where a clear floor or ground space allows a parallel approach to an element and t he high side reach is over a n obstruction, the h eight of the obsu-uct10n shall be 865 mm (34 in.) maximum, and the depth of the o bsu·uction shall be 610 mm (24 in. ) m aximum. The high side reach sha ll be 1220 mm (48 in. ) maximum for a reach depth of 255 mm (10 in.) maximum. V\7h ere the reach depth exceeds 255 mm (10 in.), the high side reach shall b e 1170 mm (46 in.) maximum for a reach depth of 610 mm (24 in. ) maximum. (See Fzgurej. 7.2.) 1'.xception No. 1: The top of washing machines and clothes dryers shall be permitted to be 915 mm (36 in.) maximum above the finish floor: Exception No. 2: Operable parts of jitel dispensers shall be permitted to be 1370 mm (54 in.) maximum, measured from the swface of the vehicular way where fuel dispensers are installed on existing curbs.

I

I :>1220 mm (:>48 in.)

?'.380mm (?'.15 in.)

------T

?'.380mm (?'.15 in.) :>255 mm (:>1 O in.)

FIGURE J.6. 1

2020 Edition

Unobstructed Forward Reach.

NATIONAL ELECTRICAL CODE

:>1220 mm (:>48 in.)

FIGURE

J. 7.1

T Unobstructed Side Reach.

70-843

AnnexJ: Accessible Design

~1220

INFORMATIVE ANNEX]

mm

1~..)llllillll---·- (Tl

~1170

L......------'k-

(~34

in.)

70-844

l

>255 mm-~610 (;,~ (>10 in.-~4 in.)

(a)

FIGURE J.7.2

mm

(~6in.)

~865mm

.,L

(b)

Obstructed High Side Reach.

NATIONAL ELECTRICAL CODE

2020 Edi tion

INDEX

Index Copyright© 2019 National Fire Protection Association. All Rights Reserved. The copyright in this index is separate and distinct from the copyright in the document that it indexes. The li censing provisions set forth for the document are not applicable to this index. This index may not be reproduced in whole or in part by any means without the express written permission ofNFPA. -A-

AC and DC conductors in same enclosure, 300.3(C) (1), 725.48 AC armored cable, see Armored cable (Type AC) Access and working space, see also Working space Audio s ig nal processing, amplification, and reproduction equipment, 640.46 Cranes and hoists, 610.57 Electrified truck parking space supply equipment, 626.22(C) Elevator machine room, 620.71 Induction and dieleccric heating equipment, 665.22 Manholes, 110.72, 110.73, 110.75 Noc over 1000 volts, 110.2 6 O ver 1000 volts, 110-111 Portable substations, 530.62 Swicchboards, 408.18 Transformers, electric sig n, 600.2 l (D) Vaults and cunnels, 110.76 Accessible Air-conditio ning a nd refrigeration disconnects, 440.14, 440.63 Arc-fault circuit-interrupter p rotectio n , 210.12 Aeries a nd roof spaces Armored cable, 320.23 Knob-and-tube wiring, 394.23 Open wiring on insu lato rs, 398.23 Cable trays, 392. 18(E), 392.1 8( F) Conduit bodies,junccion , p ull, and outlet boxes, 314.29, 314.72 (D) C ritical operatio ns power systems, 708.50 De fini tion, Art. 100 Eleccric sig ns and ligh ts, 600.42( B) G round-fault circuicinterrupcers, 210.8 Grounding eleccrode conneccion, 250.68(A) H ydromassage batlHubs, 680.73

2020 Edition

Luminaires and lampholde rs, 410.5, 410.24( B), 410.137(A) Motor disconnects, 430.107 Overcurrent de\~ces, 240.24(A) Panels, e lectrical equipmenc inscalled behind, 300.23, 368.lO( B), 725.21, 760.21, 770.21, 800.21 Readily De finition, Art. 100 Recreational vehicles site supply equip ment, 551.77(C) Sealing fittings, 501.15(C)(l), 502.15, 505.16(D)( I ); see also Hazardous (classified) locations Service overcurrent protection, 230.92 Services, 230.70(A)(l) Site-isolating device, 54 7.9 (A) (8) Splices and taps Auxiliary gutters, 366.56(A) Wireways, 376.56(A), 3 78.56 Theaters, scage switchboards, 520.21 (2) Transformers, sig ns a nd outlet lig hting, 600.21 (A) Transformers and vaults, 450.13 Accessible design, ADA standards for, Annex j AC Marking, 404.20 Motors, 430.83(C) Pa nelboards, use in, 408.36(A) Ratings, type loads, 408.36(A) AC general-use snap switch, 404. l 4(A); see also AC-DC general-use snap switch es AC modules and systems, solar photovoltaic systems, IN Fig. 690.l(b), 690.4(B), 690.6, 690.13(C) , 690.5 1 De finitions, 690.2 AC resistance and reactance conversion, Chap. 9, Table 9 AC systems Co nductor co be grounded, 250.26 Grounding co nnections, 2.~0.24(A), 250.25

NATIONAL ELECTRICAL CODE

Grounding electrode conductor, 250.66 Grounding of, 250.20, 250.30 Systems not required to be grounded, 250.21 In same metallic enclosures, 215.4(B), 300.20 ADA standards for accessible design, Annex j Adjustable speed drive and drive systems, 430.88, 430-X De finiti o ns, Art. 100 Administration and enforcement, Annex H Adoptio n of; Annex H 80..5 Application of, Annex H 80.9 Authority, Annex H 80.13 Connection to e lectricity supply, Annex H 80.25 De finiti ons, Annex H 80.2 Effective d ate, Annex H 80.35 Electrical board, Annex H 80.15 Inspector's qualificatio ns, Annex H 80.27 Liability for damages, Annex H 80.29 Notice of violations, penalties, Annex H 80.23 Occupancy of bui lding or structure, Annex H 80.11 Permits and approvals, Annex H 80.19 Plans review, Annex H 80.21 Records a nd reports, Annex H 80.17 Repeal of conflicting acts, Annex H 80.33 Title of, Annex H 80.7 Valid ity of a rticle, Annex H 80.31 Aerial cables Communications systems, 800.44 Community antenna television a nd radio distributio n systems, 820.44 Ide ntification, 200.6(A) Messenger-supported wiring, Art. 396 Network-powered broadband communications systems, 830.44 Optical fi ber cables, 770.44 Agricultural buildings, Art. 547

Bonding, 547.9, 547.10 De finitio ns, 547.2 Disconnecting means, 547.9 Distribution point, e lectrical supply to buildings o r structures from, 547.9 Equipotencial p lanes, bonding, 547.10 Feeder and service loads, calculat io n of, 220-V Grounding, 547.9 Luminaires, 547.8 Moto rs, 547.7 Overcurrent protection, 547.9 Surface temperatures, 547.4 Switches, receptacles, c ircuit breakers, controlle rs, and fuses, 54 7.6 Wiring methods, 547..5 Air conditioners, room, 440-VU Branch-circuit requirements, 440.62 Definition, 440.60 Disconnecting means, 440.63 Grounding, 440.61 Nameplate marking, 220.82(C), 440.4 Air-conditioning and refrigerating equipment, Art. 440 Arc-fault circuit-inte rrupter protection, 440.65 Branch circuits Conductors, 440-IV Ampacity, determination of; 440.6 Combination loads for, 440.34, 440.35 General, 440.31 Multi motor equipment for, 440.35 Several motor-compressors for, 440.33 Sing le motor-compressor for, 440.32 Outlets, 2l0.63(A) Selectio n curren t De finitio n , 440.2 Marking on nameplate, 440.4(C) Short-circuit an d g round-fault protection, 440-lll Equipment, for, 440.22( B)

70-845

NATIONAL E LECTRICAL CODE

Individual motor-compresso1; for, 440.22(A) Controllers for, 440- V Marking, 440.5 Rating, 440.41 Definitions, 440.2, 551.2 DisconneCling means, 440-ll Cord-connected eq uipment, 440.13 Ratings and interrupting capacity, 440.12 Room air conditioners, 440.63 Hermetic refrigerant moto 1~ compressor, see Hermetic refrigerant motor-compressors Leakage-current detectorinterrupter, 440.65 Definition, 440.2 Load, 220.82(C), 220.83 Mobile homes, 550.20 Nameplate requirements, 440.4 O verload protection, 440-Vl Application and selection ot: 440.52 8 ranch-- or 20-ampere branch circuits, 440.54 Park trailers, 5.52 .48 ( P), 552.59(B) Rated-load current Definition, 440.2 Marking on nameplate, 440.4(A) Recreational vehicles, 551.47(Q) Room air conditioners, see Air conditioners, room Single machine, when considered, 440.8 Trucks transporting refrigerated units, see Electrified truck parking space equipment Aircraft hangars, Art. .5 13 Aircraft batteries, 513.10 Aircraft elecrrical systems, 513.lO(A) Classification of locations, 513.3 Equipment, 5 13.4, 513.7, 513.8, 513.10 Ground-fault circuit interrupters, 513.12 Grounding and bonding, .5 13.16 Mobile equipment, 513.7(F), 513. IO(D) Painting hangar, 513.3(C) (2) Definition, Art. 100 Portable equipment, 513. I O(E) Sealing, 513.9

70-846

Stanchions, rostrums, and docks, 513.7(E) Wiring, 513.4, 513.7, 513.8 Air ducts, see Ducts Air plenums, see Plenums Air terminals, see Surge arresters Alarms Burgla1; see Remote-control, signaling, and powerlimited circuits Fire, 230.82(5) , 230.94 Ex. 4. See also Fire alarm systems Alarm systems, see Fire alarm systems Alternate power source , see Power source, Alternate Alterna ting-current power distribution box, 530.18(E) Definition, 530.2 Alternators, see Generators Aluminum conduit, see Rigid metal conduit Aluminum siding, grounding of, 2.50.11 6 IN Ambient temperature, 310.14(A) (3) IN No. 1, 310.14( B), Table 310.15( B) (I), Table 310.15( B)(2), 311.60( D) (4), Table 311.60( D) (4); see also Tern perature limitations Ambulatory health care centers, see also Health care facilities Essential electrical systems, 517.45 Ambulatory health care occupancies Definition, 517.2 Ampacities, see also Am paci ties,

under enlriesfor sfJecific wiring and eqttijmuml

Conductors, 310.14 through 310.21, Tables 31 i.60(C) (67) through 3ll.60(C) (86), Tables B.2(1) through B.2( I 0) Amusement attractions, 522.22 Auxiliary gutters, 366.23 Crane and hoist, Table 610.14(A) Energy storage systems, 706.30(C) Fire a larm systems, 760.51 Interconnected electric power production sources, 705.28( B) Motors, motor circuits, and controllers, 430.6 Remote control, signaling, and power-limited Class 2

and Class 3 circuits, Table 725.144 Solar photovoltaic systems, 690.8(B) Wind electric systems, 694.l 2(B) Definition, Art. 100 Feeders, 310.12(C) Fixture wires, 402.5 Grounding, 250.122 Medium voltage cable (Type MV) , 311 - IV Tables, 0- 2000 volts, Annex B Amusement attractions, control systems for p ermanent, Art. 522 Control circuits, 522- 11 Control circuits wiring methods, 522-111 Definitions, 522.2 Maintenance, 522.7 Voltage limitations, 522.5 Analgesia, relative Definition, 517 .2 Anesthetizing locations, 517-I V. See also Health care facilities Definition, 517 .2 Flammable, 517.60(A)(i), 517.60(B) (2) Ex., 517.6l(F), 517.64(F) IN Definition, 517.2 Annexes , informative, 90.5(D), Annexes A through j Antenna discharge units, 810.20, 810.57 Antenna systems, radio and television, see Community antenna television and radio distribution (CATV) systems; Radio and television equipment Apparatus, see also Associated apparatus; Intrinsically safo apparatus; Simple apparatus Associated nonincendive field wiring, 500.8(C) (6) Definition, Art. 100 Nonincendive field wiring, 508.8(C) (6) Definition, Art. 100 Appliances, Art. 422. See also Motors Battery-powered, 517.64( E) Branch circuits, see Branch circuits, appliances Construction, 422-IV Cords, see Cords, flexible Definition, Art. 100 Disconnecting means, 422- Ill

Dwelling units Disconnecting means, 422.34 Outlets, 210.52 Fixed, 550.12(D), 5.50.13(C), 55 1.42 Definition, 550.2, 551.2 Floating buildings, 555.56(B) Ground-fau lt circuit-interrupter protection, 210.8(D), 422.5 Grounding, 250-VI, 550.16, 551.54 Hazardous (classified) locations, see Hazardous (classified) locations Household cooking, demand factors and loads for, 210.2l(B)(4), Table 220.55 Installation, 422- Il Listing, 422.6 Live pares, 422.4 Load calculations, 220.14, 220.52 rhrough 220.56, Table 220.55 Marking, 422- V Mobile homes, in, 550.12(8), 550.12( D), 550.14, 550.1 5 0 ), 550.18 Motor-driven, 422.lO(A) Disconnecting means, 422.31 (C) Load, 220.18(A) Marking, 422.62 Overload protection, 422. l l (G) Outlets, 210.50(C), 210.52 Overcurrent protection, 422.11 Park u·ailers, 552.10(E)(3), 552.20( D), 5.5 2.46(B) , 552.47, 552.56(F), 552.58 Portable, 550. IS(A) (2) Definition, 550.2 Recreational vehicles, 55 1.20( D), 55 l.41 (C) Ex. I , 551.42, 551.55( F), 551.57 Signal transmission between, 517.82 Small, 210. 1 l(C)(l ), 210.52(8), 220.52(A), 550.1 2(B), 550.18, 552.46(8) (2), 552.47(A) Subject to immersion, 422 .41 Terminals, identification of; 200.lO(E) Approval, approved Definition, Art. l 00 Equip ment and materials, 90.4, 90.7, l l0.2, 500.8(B), 680.3, 680.81, 691..5,

NATIONAL ELECTRICAL CODE

2020 Edition

INDEX

705.6, 710.6, Annex H 80.19 Arc-fault circuit interrupters, 210.12 Definition, An. 100 Protection, 440.65, 550.25 Receptacle replacemems, 406.4(D) (4) Solar p hotovoltaic systems, 690. l l Arc fault protection, direct current microgrids, 712.57 Arc-flash hazard warning, l l 0.16 Arcing parts, 240.41 Enclosure ot: 110.18, 430.14(B), 51 l.7( B) (1), 513.7 (C), 515.7(B), 516.7(B), 517.61 (B) (2) Arc lamps, portable Motion p icture stud ios, 530.17 Stage equip ment, 520.61 Arc-welder motors, see Welders, electric Arc welders, see Welders, elecu-ic Arenas, 410.IO(E), Art. 518, Art. 520 Emergency lighting system, Art. 700 Armored cable (Type AC), Art. 320 Accessible attics, 320.23 Ampacity, 320.80 Bends, 320.24 Boxes and fittings, 320.40 Conductor type, 320.104 Consu-uction, 320-llJ Definition, 320.2 Equi pment grounding, 320.108 Eq ui pment grounding conductor installation, 250.120(A) E.xposed work, 320.15 Installation, 320-11 Marking, 320.120 Support, 320.30 Through or parallel to framing members, 320.17 Uses not permitted, 320.12 Uses permitted, 320.LO Armor ies, Art. 518 Emergency ligh ting system, Art. 700 Array, solar photovoltaic systems, IN Fig. 690. l (a), 690.7(C), 690.12(A), 690.12(B), 690.31 (F), 690.41 (A); see also Solar photovoltaic systems Definition, 690.2 Arresters, surge, see Surge arresters

2020 Edition

Artificially made bodies of water, see Natural and artificial ly made bodies of water, electrical wiring and equipment for Askarels Definition, Art. 100 Transformers, 450.25 Assembly occupancies, 410.lO(E), Art. 518 Classifications, 518.2 Emergency ligh ting system, Art. 700 Supply, 518.5 Theaters, audience areas, Art. 520 Wiring meth ods, 518.4 Associated apparatus Definition, Art. 100 Grounding of, 504.50(A) IN, 504.50(B ) Installation, 504.10 Listed , 504.4 Marking, 500.8(C) (6), 505.9(C) (2) Ex. 1, 505.9(C)(2) Ex. 3, Table 505.9(C) (2) (4), Table 506.9(C)(2) (3), 506.9(C)(2) Ex. Permitted equipment, 500.8(B) (2) Associated nonincendive field wiring apparatus Definition, Art. 100 Marking, 500.8(C) (6) Atmospheric groups, see Hazardous (classified) locations Attachment fittings, 210.8(A) ( lO) Ex., 210.8( B) (10) Ex., 314.27( E), 422.22, 422.33(A) Defin ition, Art. 100 Attachment plugs (caps), see also Hazardous (classified) locations; Receptacles, cord con nectors, and attach ment p lugs (caps) Construction of, 406.7 Definition, Art. 100 Flexib le cords on, 210.50(B), 400.lO( B), 400.24 Grounding type, 406.10 Po larized, terminal identification , 200. I O(B) Attics

Armored cable, 320.23 Knob and tube, 394.23 Lighting outlets required, 210.70(C) Metal-clad cable, 330.23 Nonmetallic extensions, 382.12(1)

NATIONAL ELECTRICAL CODE

Nonmetallic-sheathed cable, 334.23 Open wiring, 398.23 Sign u-ansformers in, 600.21 (E) Audio signal p rocessing, amplification, and reproduction equipment, Art. 640 Access, 640.5, 640.46 Conduit or tubing, 640.23 Definitions, 640.2 Environmental protection, 640.44 Flexible cords, use of, 640.21, 640.42, 640.4.5 Grounding, 640.7 Grouping of conductors, 640.8 Locations, 640.3 Loudspeakers Definition, 640 .2 In fi re-resistant construction, 640.25 Mechanical execution of work, 640.6 Motion picture projectors, 540 .50 Permanent installations, 640-11 Portable and temporary installations, 640-lll Protection of elecu-ical equipment, 640.4 Theaters, 520.4 Transformers, 640.9 (D) Definition, 640 .2 Underwater, 680.27(A), 680.35(D), 680.43(G), 680.45(D) Water, near, 640.10 Wireways, gutters, auxiliary gutters, 640.24 Wiring methods, 640.9 Wiring of equipment racks, 640.22, 640.43 Auditoriums, Art. 518, Art. 520 Emergency lighting system, Art. 700 Authority h aving jurisdiction, 90.4; see also Approval, approved Definition, Art. 100 Automatic Defin ition, Art. 100 Autotransformers, see Transformers Auxiliary gutters, Art. 366 Conductors Ampacities, 366.23 Clearance, bare live parts, 366. IOO(E) Insulated, 366.58 Number ot: 366.22

Construction specifications, 366III

Covers, 366.I OO(D) Definitions, 366.2 Extension beyond equipment, 366.12 Grounding, 366.60 Indoors Listing, 366.6(B) Marking, 366.120(B) Uses permitted, 366.IO(A) (I ), 366.10( B)(2) Installation, 366-ll Listing, 366.6 Marking, 366.120 Metallic Conductors, 366.22 (A), 366.23(A) Definition, 366.2 Securing and supporting, 366.30(A) Uses permitted, 366. IO (A) Nonmetallic Conductors, 366.22( B), 366.23(B) Definition, 366.2 Mark ing, 366. 120 Securing and supporting, 366.30(B) Uses permitted, 366. IO(B) Outdoors Listing, 366.6(A) Marking, 366. 120(A) Uses permitted, 366. IO (A)( l ), 366. I O(B) ( I ) Sound recording, sim ilar equipment, 640.7(A), 640.24 Splices and taps, 366.56 Support, 366.30 Uses not permitted, 366.12 Uses permitted, 366.10 -B-

Back-fed devices, 408.36(D) Backfill, 300.5(F), 300.50(E) Balconies, outdoor, receptacles for, 2 10.52(E)(3) Ballasts, electric discharge lamps, 410-Xll, 410-XJJI Protection in fluorescent fixtures, 41O.l30(E) Protection in recessed HID fixtures, 4 10.130(F) Bare conductors Ampacities, 310. 15(D) Auxiliary gutters, 366.56(B) Bondingjumpers, 250. 194(A) Contact conductors, cranes and hoists, 610-lll

70-847

NATIONAL ELECTRICAL CODE

Definition, Art. 100 Equipment grounding conductors, l l0.54(B) , 225.4Ex., 250.118(1), 2.50.119, 250.120, 250.18 7(D) Grounded conductors, 225.4 Ex., 230.22 Ex., 230.30(A) Ex., 230.41. Ex. Lighting systems operating at 30 volts or less, 411.6(C) Raceways, 225.27, 230.30(A) Ex. Service entrance, Types SE, USE, 338.100 Sizing conduits for, Chap. 9 Underground conduits, grounded neutral , 230.30(A) Ex., 230.41 Ex. Barriers, 368.234 (8 ) Basements (cellars) Lighting outJets required, 210.70(C) Nonmetallic extensions, 382.12 ( l) Nonmetallic sheathed cable, 334.15(C) Receptacles in, 210.8(A) (5), 210.52(G) Basic care space, 517.29(A) Definition, 517.2 Bathrooms, see also Bath nibs Branch circuits for, 210.11 (C) (3) Definition, Art. 100 Disconnecting means, 230.70(A) (2)

Fixed electric space-hearing equipm e nt cables, 424.44 (E) Lighting outJets required , 210.70(A)( l ), 210.70(8 ) O vercurre nt devices, 240.24(E) Receptacles in, 210.8(A) (1), 210.8(B) ( 1), 210.52(D), 406.9(C), 550.1 2(E), 550.13(D) through (F), 5.51.41 (C), 552.41 (F) Bathtubs Hydro massage, 680-Vll Definition, 680.2 Fixed electric space-h eating equipment cables, 424.44(E) Luminaires, 410.lO(D), 550.14 (D), 551.53(8), 552.54(8 ) Receptacles, 210.8(A) (9), 406.9(C), 550.1 3(F), 5.52.41 (F) Switches, 404.4(C) Batteries, see also Storage batteries

70-848

Aircraft, 513.10 Flow, 706--V Definition, 706.2 Installations, Art. 480 Marking, 480.7(F), 480.7(G) Nominal voltage Definition, 480.2 Sealed Definition, 480.2 Vents, 480.11 (B) Terminal, see Terminals Battery charging equipment, 51 1.lO (A) Aircraft hangars, 513.lO(B) Battery system, see alrn Storage batteries Definition, Art. 100 Bedrooms Arc-fault circuit-interrupter protection, 210.12(A) Bell circuits, see Remote-control, signaling, and powerlimited circuits Bends, 300.34, Chap. 9, Table 2; see alsa;;pecific wiring system Berths Definition, 555.2 Bipolar circuits, 690.7 ( C), 690.31 (E) Definition, 690.2 Block (city, town, or village) Communication wires Protective devices, 80.5.90(A) Underground block disu-ibution, 805.47(B) De finition, 800.2 Network-powered broadband co mmunications systems, protection, 830.90(A) Boathouses and boat hoists, ground-fault circuit interrupters, 210.8(A) (8)

Boatyards, see Marinas, boatyards, fl oating buildings, and docking facilities Bodies, conduit, see Conduit bodies Boilers Electrode-type 600 volts or less, 424-VIII Over 1000 volts, 490-V Resistance-type, 424-Vll Bonding, 250-V Agriculmral buildings, 547.9, 547.10 Aircraft hangars, 513 .16 Bulk srorage p lants, 515.16 Cable trays, 392.60

Carnivals, circuses, fairs, and similar events, 525-IV CATV and radio distribution systems, 820.100 Communications circuits, 800.100, 800.106(8) Cranes and hoists, 610- Vl l Definition, Art. 100 Electrolytic cells, 668.30(E) Elevators, 620-LX Equipotential p lane, 547.10, 680.26, 682.33 Flexible metal conduit (Type FMC) , 348.60 Garages, commercial, .511.16 Grounding-type receptacles, 250.146 Hazardous (classified) locations, see Hazardous (classified) locations Health care facilities, 5 l 7.13(B), 517.19( D), 517.19(E) Induction and dielectric heating equipment, 665.26 Informatio n technology equipment, 645.15 lnte rsystem bonding termination, 545.27, 770.lOO(B) Definition, Art. I 00 Intrinsically safe systems, 504.60 Irrigation machines, 675.14 Liquidtight flexible metal conduit (Type LFMC), 350.60 Liquidtight flexible nonmetallic conduit (Type LFNC), 356.60 Loosely jointed raceways, 250.98 Manufactured buildings, .545.11 Marinas and boatyards, 555. 13 Metal boxes, 314.4 Mobile homes, 550.16(C) Motor ti.tel dispensing facilities, 514.16 Naturally and artificially made bodies of water, electrical equipment for, 682- lll Optical fibe r cables, 760.180, 770.100, 770.106(8) Other enclosures, 250.96 Omside raceway, 250.102(E) Ove r 250 volts, 250.9 7 Over lOOO volts, 490.74 Panelboards, 408 .40, 517.14 Park trailers, 552.57 Piping systems and exposed structural steel, 250. 104 Raceways, see Raceways

Radio and television equipment, 8 10.2 1, 810.58 Receptacles, 250. 146 Rec reational vehicles, 5.51.5.5(A), 5.5 l.55 (B), 551.56 Relocatable strucmres, 545.26, 545.27 Separately d e rived systems, 250.30 (A) (8), 250.30 (8 ) (3), 250.104(D) Service equipmem, 250.92, 250.94 Signs and outline lighting, 600. 7(B), 600.33(D) Substations, fences and othe r metal so-uctures e nclosing, 250.194 S"imming pools, see Swimming pools Tunnels, 110.54 Wind e lectric systems, 694-V Bonding conductors, 517.l 9 (D), 545.26, 547.lO (B), 55l.56(C), 552.57(C), 680.74(B), 760.1 80, 770. 100, 800.100, 810.21, 8 10.58, Chap. 9, Note 3 Bonding jumpers, see.Jumpe rs, bonding Bored ho les through studs, joists, 300.4 (A) (1) Bowling alleys, Art. 5 18 Emergency lighting system, Art. 700 Boxes (ou tle t, device, pull, and junction) , Art. 3 14. See also Hazardous (classified) locations Accessibility, 314.29, 3 14.72(D) Agriculniral buildings, 547.5(C) Alternating-current power distribution box, 530.18(E) Definition, 530.2 Community antenna television and radio distribution systems, 820.133(A)(l) Concealed work, 314.20 Conductors, numbe r in box, 314.1 6 Entering boxes, conduit bodies or fi ttings, 314. 17 Construction specificatio ns, 314111

Covers, 314.25, 314.28(C), 314.41, 314.42, 314.72(E) Cutout, see Cabinets, cmout boxes, and meter socket e nclosures

NATIONAL ELECTRICAL CODE

2020 Edi tion

INDEX

Damp locations, 314.15 Depth , minimtm1, 314.24 Drop (th eaters, etc.), 520.44, 520.46 Definition, 520.2 Enclos ures, handho le, 314.29, 314.30 Fill calculations, 314.16( B) Fire pumps, 695.6(H), 695.6( !) Fire resistive system , 728.5 (E) Floor, for receptacles, 314.27(B) Flush-mounted installations, 314.19 Grounding, 250.148, 250- VI Gutters, auxiliary, used as, 366.58( B) Insulating, see Boxes, nonmetallic Junction, pull, seeJunction boxes Ligh ting (luminaires) outlets, see Lighting outlets Marking, 314.44 Metal Construction, 314.40, 3 14-III Grounding and bonding, 3 14.4 Installation, 314-11 Wireways used as pu ll boxes, 376.23(B) Mobile h o mes, 550 .15 (!) Multioutlet assemblies used as pull boxes, 380.23(B) Neon transformer enclosures used as, 600.5(D)(2) Network-powered broadband communications systems, 830.l33(A) (1) Nonmetallic, 314.3, 314.17(C), 314.43, 334.40 Receptacles installed in, 406.3(D) (2) Wireways used as pull boxes, 378.23(B ) Not required , 590.4(G) Ex . I Optical fiber cables in, 770.133( B) O ver 1000 volts, 314-IV Park traile rs, 5.52.48, 552.56( D) Plugging, see Plugging boxes, motion p icture studios Portable Rides, tents, and concessions, 525.22 Theaters, 520.62 Recrea tional vehicles, 551.47 Repairing noncombustible sur faces, 314.21 Required location, 300.15 Round, 314.2

2020 Edition

Securing and supporting, 300.11, 314.23, 392.1 8(G) Snap switch es over 300 volts, not ganged, 404.8( B) Solar p hotovoltaic systems, 690.34 Surface extensions, 3 14.22 Temporary installations, 590.4(G) Unused openings, closed , 1 l0. 12(A) Vertical raceway runs, 300.1 9 Volume calculations, 3 14.16(A) Wall or ceiling, 314.27(A) Wet locations, 314.15 Branch circuits, ArL 210, An. 220 Air conditioners, 440-lV, 440Vll Appliances, 210.23, 422-11 Calculations, 220- 11 Definition, ArL 100 Small, 210.11 (C) ( 1) Arc-fault circuit-imerrupte r protection, 210.12 Audio equipmem, 640. lO(A) , 640.41, 640.42( E) Bathrooms, 210.l l (C)(3) Breakom assembly, 520.68(A) (6) Definition, 520.2 Busways as branch circuits, 368.17 (C) Calculation of loads, 220- 11, Annex D Co lor code, 210.5 Common area, 210.25(B) Co nducto rs, minimum ampacity and size, 210.19 Critical, 517.34,517.44 De finition, 517.2 Critical operations power system s, 708-11, 708.30 De finition, Art. 100 Electric vehicle supply eq uipment, 62.5.40, 625.41, 625.47 Electroplating, 669.5 Elevawrs, dumbwaite rs, escalators, etc., 620.1 3 Emergency ligh ting transfer switch , 700.25 De finition, 700.2 Emergency systems, 700.12 (1) (2), 700.15, 700.17, 700.18, 700.25 Ene rgy manageme nt systems, 750.30 (C) Fire a larm systems, 760.41 (B), 760.121 (B) Fixed electric space-heating equipment, 424.4

NATIONAL ELECTRICAL CODE

Boilers, 424.82 Low-voltage equipmem, 424. I 04 Radiam heating panels, 424.95, 424.96 Fixed resistance and e lectrode industrial process heati ng equipmem, 425.4, 425.22(A). 425.22(D) Electrode-type bo ilers, 425.82 Resistance-type boile rs, 42.5.72(D) General-purpose Defin ition, ArL 100 Guest rooms or suites, 210.6(A), 210.17 Healtl1 care facilities, 5 17.18(A), 517.63( B), 517.63(C), 517.73(A)( l ) Individual Defin ition, ArL 100 Ove rcurrent protection, 210.20 Permissible load s, 2 10.22 Rating or setting, 430 .52 Required, 490.72, 600.5, 60.5.9( B), 620.22 tl1rough 620.25 Information technology equipmem, 645.5 Irrigation machines, 675.9, 675.10 Isolated power systems, 517.160 Low-voltage suspended ceiling power distribution systems, 393.21 (B) Ma rinas, boatyards, floating bu ildings, a nd d ockyards, 555.32 (A) (3), 55.5.34(B) (2), 555.35 (A) (3), 555.37(D), 555.53 Maximw11 loads, 220.18 Mobile homes, 550. l l , 550. 12 Modular data centers, 646.7(B) Mowr, on indh~dual branch circuit, see Mo tors Multiple, 210.7 Multiple-outlet, 210.23, 210.24, Table 210.24 Multiwire, 210.4, 393.21(B) Defin ition, An. 100 Outside, see Omside branch circuits and feeders Overcurre nt device, 240.24( B) (2)

Definition, ArL 100 Overcurre nt protection, 210.20, 240.4, 250.32(B) (2), 250.32(C) (2 ), 520.52 Park traile rs, 552.42, 552.46 Patient bed location, 517.IS(A), 517.19(A)

Pe rmissible loads, 210.22, 210.23 Pie rs, 682. 15( B) Ratings, 210-11 Recreational vehicles, 5.51.42 Requirements for, 210.24, Table 210.24 Selection current, 440.4(C) Definition , 440.2 Sho re power, 555.33(A)(3) Small-appliance, 210.11 (C) ( l ) Stage or set, 530.23 Swimming pools, 680.23(F) Taps from, 210.19(A), Table 210.24, 240.4( E), 240.5 (B) (2) Through luminaires, 410.64(C) Voltage d rop, 210.1 9(A) IN No.

3 Voltage limitations, 210.6 X-ray equ ipme nt, 517- V, 660.4, 660.6 (A) Branch-circuit selection current Definition , 440.2 Marking on nameplate, 440.4 (C) Building Definition,An. 100 First fl oor ot: 362.10 Building component Definition , 545.2 Building system Definition, 54.5.2 Building wire, see Conducto rs Bulkhead De finitio n , 555.2 Bulk storage p lants, An. 515. See alrn Hazardous (classified) locations Class I locations, 515.3 Gasoline dispensing, 515.10 Grounding and bonding, 5 15.16 Seal ing, 515.9 Underground wiring, 5 15.8 Wiring and equipment, 515.4, 515.7 Bull switches, 530.15(D ) Definition, 530.2 Burglar alarm systems, see Remote-control, signaling, and powerlimi ted ci rcuits Busbars Aboveground wiring metl1ods, 300.3 7 De fini tion, 393.2 Industrial co ntrol panels, 409.102 Interconnected electric power production sources, 70.5.12(B)(3) Moto r con trol cemers, 430.97

70-849

NATIONAL ELECTRICAL CODE

Porcable dislribution or lermination boxes, 525.22(B) Porcable srage equipment, 520.62 (C) Swilchboards, 408.3, 408.51 Bushings Cord, luminaire, 410.84 Eleclrical nonmelallic rubing, 362.46 Fiber, 320.40 Fire alarm syslems, 760.3(K) Generalors, 445.16 High density polyelhylene conduit, 353.46 Insulated, 300.4(G), 312.6(C) Lampho lders alcached lo flexible cord, 410.62(A) Securing filti ngs or raceways, 300.4(G) lntermediale metal condui l, 342 .46 Motors, 430.13 Outlel boxes, conduil bodies, and outlel filtings, 314.42 Reinforced lhermosetting resin conduil, 355.46 Rigid mecal cond uit, 344.46 Rigid polyvinyl chloride conduil, 352.46 Snow-melting and deicing equipment, 426.22 (C) Underground inslallations, 300.5 (H ) Use in lieu of box or lerm inal lilting, 300.16(B) Busways, ArL 368 Barriers, fire , 368.234(B) Branches from, 368.56 Connections, 368.238 Construclion, 368.--111 Dead ends closed, 368.58 Definition, 368.2 Drains, 368.236 Exlension through walls and floors, 368.lO(C) Feeder or branch circuits, 368.17 Grounding, 368.60 Over 1000 volts, 368.260 Installation, 368.--11 Luminaires connecled lO, 410.36(F) Manufacrured wiring systems, 604.lOO(A) (4) Marking, 368.120, 368.320 Overcurrent prolection, 368.17 Over 1000 volts, 368.--IV Reduction in size, 368.17(B) Seals, vapor, 368.234(A)

70-850

Swrage bauery, disconnection means, 480.7(E) Support, 368.30 Terminalions, 368.238 Under 1000 volts, 368.240 Through walls and floors, 368.IO(C) Uses nol perm iued, 368.12 Uses permiued, 368.10 Ventilated enclosures, 368.237 Bypass isolation S\\itch, 700.5(B), 701.5(B), 708.24 Definition, ArL 100 -C-

Cabinets, cutout boxes, and meter socket enclosures, Art. 312 Construction specifications, 31211

Damp and wel locations, 312.2 Definitions, Art. 100 Defleclion of conducwrs, 312.6 Installation, 312-l Insulation al bushings, 300.4(G), 312.6(C) Marking, 230.66(B) Posilion in walls, 312.3 Swilch enclosures, splices, taps, 312.8 Unused openings, 110.12(A) Wire-bending space at terminals, 312.6(B) Wiring space, side or back, 312.9 Cable bending, see type of cable Cablebus, Art. 370 ConduClors, 370.20 Ampacily, 370.80 Overcurrent protection, 370.23 Terminalions, 370.20( B), 370.42(3) Construction specifications, 370lll

Definilion, 370.2 Equipmenl grounding conduClor inscallation, 250.120(A) Fittings, 370.42 Grounding, 370.60 lnslallation, 370-11 Marking, 370.120 Securing and supporting, 370.30 Support and extension lhrough walls and floors, 370.1 8 Uses nol permilled, 370-12 Uses permiued, 370.10 Cable connectors Definition, 324.2 Theater, 520.67

Cable end fittings, changing from cable to knob-andtube, 300.16(A) Cable management system, 625.17(C), 626.23, 626.25 (B) (3) Definition, 625 .2, 626.2 Cable routing assembly, 800.26, 800.110, 800.113, 800.154, 800.1 82, 805.133(A)(l) Coaxial cables, 820.133(A) (1) Definition, Art. 100 Network -powered broadband communications systems, 830.133 (A) ( I) Premises-powered broadband communications systems, 840.l 70(D) Cables Abandoned, 640.6( B) Audio dislribution, 640.2 Communications, 800.25 Definition, 800.2 Fire alarm, 760.25 Definition, 760.2 Interconnecting Definition, 645.2 Optical fiber, 770.25 Definition, 770.2 Premises-powered broadband communication, 840.25 Remote-control, signaling, and power-limi ted circuits, 725.25 Definition, 725.2 Adjustment factors for more tlrnn three currenlcarrying conductors in, Table B.2 (11) Aerial, see Aerial cables Armored (Type AC), see Armored cable (Type AC) Border lights, tl1eater, 520.44(C) Bundled Definition, 520.2, 725.2 Cable trays, installation in, see Cable trays CATV, Art. 820 Circuit integri cy, 725 .179 ( F), 760.24(B), 760.179(G), 770.179(£) Communications, 805.179(C) Definition, 805.2 Coaxial, ArL 820, 840.1 IN, 840.47(C), 840.48(C), 840.93(C), 840.101 (A) Definition, Art. I 00 Continuily, 300.12 Definition, 805.2

Feswon, 610. 13(C) Definition, 610.2 Fial cable assemblies (Type FC), SI'£ Flat cable assemblies (Type FC) Fial conduClor (Type FCC), see Flat conduclor cable (Type FCC) Flexible, see Cords, Flexible Grouped, 520.2.54(C), 620.2l (A) Definition, 520.2 Heating, Art. 424 Installation in cable trays, see Cable trays Installed in grooves, 300.4(F) lnstrumencation tray (Type !TC) , see lnstnunentation tray cable (Type ITC) lnlegrated gas spacer cable (Type IGS), see lnlegraled gas spacer cable (Type IGS) lmerconnecting, 645.5 Definition, 64.5.2 Manufactured wiring syslems, 604.lOO(A) Medium vo ltage cable (Type !VIV), see Medium voltage cable (Type MV) Mecal-clad cable (Type MC), see Metal-clad cable (Type MC) Mineral-insulated metalsheatl1ed (Type Ml) , see Mineral-insulaled melalsheatl1ed cable (Type Ml) Multiconductor cables, identification of conductors in, 250.l 19(B) Nonmetallic exlension, see Nonmetallic exlensions Nonmecallic-shemhed (Types NM, NMC, and NMS), see Nonmecallicsheatlled cable (Types NM, NMC, and NMS) Nonmelallic underground conduil witll conductors, see Nonmelallic underground conduit wilh conduclors Optical fiber, see Optical fiber cables Otl1er types of, see systems, e .g. Communily anlenna lelevision and radio distribution (CATV) systems

NATIONAL ELECTRICAL CODE

2020 Edition

INDEX

Point of entrance Definition, 770.2, 800.2 Portable, see Cords, flexible Portable power cables, marinas and boaryards, 555.34(A) (2 ), 555.34( B) (3) Power and control tray cable (Type TC) , see Power and control tray cable (Type TC) Preassembled in nonmetallic conduit, see Nonmetallic underground conduit with conductors Protection against physical damage, 300.4 Sealing, 50l.15(D), .50l.l5 (E) , 505.16(A)(2), 505.16(B) (5) through (B)(7), 505.16(C) (2) Secured, 300.11 , 314.l 7 (B ) Service, see also Service-en trance cable (Types SE and USE) Definition, Art. 100 Service-enu-ance (Types SE and USE), see Servicee ntrance cable (Types SE and USE) Splices in boxes, 300.15 Stage, 530.18 Support, 110.12(C), 392.1 8(G ) Through studs,joists, rafters, 300.4 Traveling, elevator, 620. 11 (B), 620.12(A), 620-V Two-fer, 520.69 De finitio n, 520.2 Type P, see Type P cable Underground, 230-III, 300.5, 300.50, 770.47 Underg round feeder and branch circuit Type UF, see Underground feeder and branchcircuit cable (Type VF) Vehicle supply equi pment, 625 .17, 626.23 through 626.25 Definitions, 625.2, 626.2 We lding, 630-IV Cable sheath Definition, 770.2, 800.2 Cable suspension , 300.19 Cable trays, ArL 392 Accessibiliry, 392.18(E), 392.18(F) Ampacity, 320.80(B), 392.80 Bends, 392.1 8(A) Bonding, 392.60 Bus hed conduit and nibing, 392.46

2020 Edition

Cable and conductor installation, 392.20 Cable fill, 392.22 Class I circuits, 725.48( B)(4 ), 725.51 Communications circuits in, 800.110, 800.ll3( H) Community antenna television and radio distribution system s, 820.1 33(A) (1) Construction speci fications, 392lll Covers, 392.18(C) Definition, 392.2 Equipment grounding co nductor installation, 2.50.120(A) Exposed, 392.18( E) Fire a larm system co nductors, 760.5 l(C), 760.133, 760.139 Fire resistive system, 728.5 (D) Grounding, 392.60 Installation, 392-11 Marking, 392.18( H) Maximum numbe r of cables in, Tables C.14 through C.20 Network-powered broadband co mmunications systems, 830.133(A) (1) Optical fiber cables, 770.11 3(1-1), 770.133, Table 770.154 (a) Outdoors, 725.1 35(H) Over 1000 volts, cables rated, 392.20 Over 2000 volts, cables rated, 392.80( B) Photovoltaic systems, 690.31 (C) (2) Plen urns, 300.22 (C) (2) Securing a nd supporting, 392.30 Splices, cable, 392.56 Support for raceways, cables, boxes, and conduit bodies, 392 .18(G ) Through partitions and walls, 392.18(D) Uses not permitted, 392.12 Uses permitted, 230.44, 392.10 Ventilated , 392.22 Wiring methods, 392. lO (A), Table 392. lO(A) Calculations, Annex D; see also Loads Camping trailer, .'W!e alrn Recreational vehicles (camping traile rs, motor horn es, park trailers, travel traile rs, truck campers)

NATIONAL ELECTRICAL CODE

Definition, 551.2 Canopies Boxes and fittings, 314.25 Live parts, exposed, 410.5 Lum in a ires fixtures Conductors, space for, 410.20 Cover At boxes, 410.22 Combustible finishes, covering required between canopy and box, 4!0.23 Capacitors, Art. 460. See also Hazardous (classified) locations Definition, 460.2 Enclosing and guarding, 460. 3 Induction and dielectric heating, 665.24 Installatio n, Art. 460 Moto rs, 430.27, 460.9 1000 volts and unde t; 460- 1 Conductors, 460.8 Grounding, 460.10 Marking, 460.12 Means of discharge, 460.6 Overcurre nt protection, 460.8( B) Rating or setting of motor overload device, 460.9 Over I 000 volts, 460-11 Grounding, 460.27 Identification, 460.26 Means for discharge, 460.28 Overcurre nt protection, 460.25 Switching, 460.24 Phase converters, 455.23 Safe zone De finition, 460.2 X-ray equipment, 517. 76, 660-III Caps, see Attachme nt p lugs Carnivals, circuses, fairs, and similar events, ArL 525 Conductor overhead clearance, 525 .5 De finitions, 525.2 Grounding and bonding, 525- IV Equipment bonding, 525.30 Equipment grounding, 525.31, 525.32 Grounding conductor continuiry assurance, 525.32 Power sources, 525-11 Multiple sources of supply, 525.11 Services, 525.10 Protection of electrical equipme nt, 525.6, 525.23 Wiring methods, 525--111

Concessions, 525.21 Ground-fault circuitinte rrup ter protection, 525.23 Portable distribution or terminal boxes, 525.22 Rides, 525.21 Te n ts, 525.21 Cartridge fuses, 240-VI Disconnection, 240.40 CATV systems, Se£ Communiry antenna television and radio distributio n (CATV) systems Ceiling fans, 680.22(B), 680.43(B) Support, 314.27(C), 422. 18 Cell Cellu lar conc rete fl oor raceways Definition, 3 72.2 Cellu lar metal floor raceways Definition , 374.2 Electrol ytic, Se£ Electrolytic cells Fuel, Art. 100; see also Fue l cell systems Inte rcell connectors, 480.4(B) Definition, 480.2 lnte rtie r connectors, 480.4 (B) Definition , 480.2 Solar, IN Fig. 690. 1 (a) Definition , 690.2 Storage batteries, 480.4, 480. ll (B) Definition, 480.2 Cellars, see Basemen ts Cell line, electrolytic cells, Se£ Electrolytic cells Cellular concrete floor raceways, ArL 372 Ampaciry of conductors, 372 .23 Connection to cabinets and other e nclosures, 372.18(B) De finitio ns, 372.2 Discontinued outlets, 372.58 Header, 372.1 8(A) Installation, 372-11 J unction boxes, 372. 18(C) Markers, 372.18(E) Number of conductors, 372.22 Size of conductors, 372 .20 Splices and taps, 372.56 Uses not permitted, 372.12 Cellular metal floo r raceways, ArL 374 Ampaciry of conductors, 374.23 Connection to cabinets and extension from cells, 374. 18(A) Construction, 374-lll De finitions, 374.2

70-851

NATIONAL ELECTRICAL CODE

Discontinued ourJets, 374.58 Inserts, 374.18(C) Installation, 374-LI Junction boxes, 374.18(B) Markers, 3 74.18(D) Number of conductors, 374.22 Size of conductors, 374.20 Splices and taps, 374.56 Uses not permitted, 374.12 Chairlifts, see Elevators, dumbwaiters, escalators, moving walks, p latform lifis, and stairway chairlifts Charge controllers Definition, Art. 100, 694.2 Energy storage systems, 706.33 Solar photovoltaic systems, 690.72 Charger power converter, 625.102 Definition, 625.2 Child care facility Definition, 406.2 Tamper-resistant receptacles in, 406.12 (3) Churches, Art. 518 Cinder fill Electrical metallic tubing, 358.lO(C) High density polyerJ1ylene conduit, 353.10(3) Intermediate or rigid metal conduits and electrical metallic tubing, in or Lmder, 342.IO(C) , 344.IO(C) Nonmetallic underground conduit with conductors, 354.10(3) Reinforcing thermosetting resin conduit, 355.lO(C) Rigid polyvinyl chloride conduit, 352.IO(C) Circuit breakers, Art. 240. S& also Hazardous (classified) locations Accessibility and grouping, 404.8(A) Agricultural buildings, 547.6 Arc energy reduction, 240.87 Circuits over 1000 vo lts, 490.21, 490.45, 490.46 Damp or wet locations, in, 404.4 Definition, Art. LOO Disconnection of grounded circuits, 404.2( B), 514. ll (A) Enclosures, 404.3 Fixed electric heating equipment for pipelines and vessels, 427.5.5(A)

70-852

Fixed resistance and electrode industrial process heating equipment, supply conductors, 425.21 General, 110.9, 240- 1 Indicating, 240.8 1, 404.7, 422.35, 425.21 Markings, 240.83, 240.86(A) Mobile homes, .550. ll (C) Overcurrent protection, 230.208, 240-1, 240-Vll Generators, 445.12 Motors, 250.122( D), 430.52, 430.58, 430.111 , 430.225(C) (1) Transformers, 450.3 Panelboards, 408-111 , 408.54, 408.55 Ex.I Ra ting Fixed-trip circuit breakers, 240.6(A), 240.83(C), 240.86 Motor branch circuits, 430.58 Service disconnecting means, 230.70, 230.205 Service overcurrent protec tion, 230.90, 230.91 Stand-alone systems, 7 10.15(F) Switches, use as, 240.83( D), 404.11, 410.14l(A) Switching devices, over 1000 volts Definition, Art. 100 Circuit directory, panelboards, 408.4 Circuit integrity cables, 72.5.179 (F) , 770.!79( E) Co mmunications, 805.l 79(C) De finition, Art. 100, 760.2, 805.2 Fire a larm systems, 760.24( B), 760.53( B) (2), 760.154, 760.176( F), 760.179(G) Circuit interrupters, groundfault, see Ground-fault circuit interrupte rs Circuits Abandoned supply circuits, 645.5(G) De finition, 645.2 Anesthetizing locations, 517.63 Branch, see Branch circuits Burglar alarm, see Remotecontrol, signaling, and power-limited circuits Central station, see Fire alarm systems Communication, s& Communications circuits Control, see Control circuits

Diffe re nt intrinsically safe, 504.30(B) Definition, Art. 100 Electrical circuit protective system, 250.120(A) IN, 300.l 9( B) Definition, Art. 100 Fire alarm, see Fire alarm systems Fuel cell systems, see Fuel cell systems Grounding, Art. 250 Im pedance, 110.10 Information technology equipme nt, 645.5 Inte rconnected electric power production sources, 705.28 Intrinsically safo, 504.30 Inverter input and output circuits, 690. l , 690.8(A)(J), 690.10 Less than 50 volts, Art. 720 Class 1, 725-11 Grounding, 250.20(A) Modular data centers, 646.6 through 646.8, 646.17, 646.20 Motor, 430-11 Motor control, 430-VI Number of, in e nclosures, 90.8( B) Outpu t, see Output circuits Over 600 vol ts, see Over 600 volts Over 1000 volts, see O ver 1000 vo lts Photovoltaic systems, 690.6, 690-LI , 690-IV Definitions, 690.2 Inverter circuits, 690.6 Output circuits, 690.l, 690.6(B), 690.7 rJuough 690.9, 690.31 Definition, 690.2 Source circuits, 690.l, 690.7 through 690.9, 690.3 1, 690.5 3 Definition, 690.2 Power-limited, s& Remotecontrol, signaling, and power-limi ted circuits Premises communications Definition, 840.2 Premises community antenna television (CATV), 840.170(F) Premises community antenna television (CATV) circuits Definition, 840.2 Protectors required, communications

circuits, 800.100, 800. 106, 805.90, 805.170, 830.90 Remote-control, see Remotecontrol, signaling, and power-limited circuits Signal, see Remote-control, ~ signaling, and powe rlimited circuits Telegraph, see Communications circuits Telephone, see Communications circuits Underground, s& Communications circuits Ungrounded, 210. 10, 2 15.7, 410.93; see also Conductors Wind e lectric systems, 694-11, 694.30(C) Definitions, 694.2 Circuses, see Carnivals, circuses, fairs, and similar events Clamp fill , b oxes, 314.16(B) (2) Clamps, ground, 250.10, 250.70 Class I , 2, and 3 circuits, s& Remote-control, signaling, and powerlimited circuits Class I, II, and III locations, see Hazardous (classified) locations Clean surfaces, grounding conductor connections, 250.12 Clearances, see also Enclosures; Space Ante nnas, 810.13, 810. 18, 8 10.54 Co mmunity ante nna systems, 820.44(B), 820.47, 820.133(A) Conductors Open, outside branch circuits and feeders, 225.18, 225. 19 Overhead service, 2 30.24, 230.26, 551 .79 Elevators, dumbwaiters, escalators, etc., 620.5 Fixed resistance and electrode industrial process heating equipment, supply conductors, 425. 13 Live part.~ Auxiliary gutters, 366. IOO(E) Circuits over 1000 volts, 110111 Lt1111inaires, 410.116, 410. 136 Network-powered broadband communications systems, 830.44 Swimming pools, 680.9

NATIONAL ELECTRICAL CODE

2020 Edition

INDEX

Switchboards, 408.5, 408. 18 Wind e lectric systems, 694.7(G) Climbing space, line conductors on poles, 225.l4(D) Clothes closets Definition, Art. 100 Heating, 424.38(C) Luminaires, 410.16 Overcurrent d evices, 240.24(D) Clothes dryers Calculations for, 220.54 Feeder demand facrors, Table 220.54, 220.82(B) Grounding, 250.114, 250.140 Mobile homes, 550.15(E) , 5.50.16(A), 550.16( B)(3) Clothing manufacturing plants, 500.5(D), Art. 503, Art. 506. See also Hazardous (classified) locations CO/ ALR Receptacles, 406.3(C) Switches, 404.14(C) Collector rings, 490 .54 , 675.11 Definition, 675.2 Collectors, cranes and hoists, 610.22 Color code Branch circuits, 210.5 Conductors, 311.14, 4!0.69, 504.80(C), 647.4(C) Extra-hard-usage cables, 520.44 (C) (3) Grounded conductor, 200.6, 200.7, 400.22 , 520.44(C) (3), 520.540)(1 ) Grounding conductor, 250.119, 311.14, 400.23, 520.44 (C) (3) Iso lated power systems, 5 17.160(A) (5) Ungrounded , 2l0.5(C), 215.12(C) , 3 11.14 Higher voltage to g round Sensitive electronic equi pment, 647.4(C) Sen1ce-e ntrance conductors, 230.56 Combustible dusts, Art. 502, Art. 506; see also Hazardous (classified) locations Definitio n, Art. 100 Combustible gas detection systems, 500.7 (K), 505.8(1) Definition, Art. 100 Combustible-liquid produced vapors, see H azardous (classified) locations

2020 Edition

Commercial garages, see Garages, commercial Common grounding electrode, 250.58 Common neutral Feeders, 21 5.4 Outside wiring, 225.7(B) Communications circuits, Art. 800, Art. 805; Sl!I! also Com munications systems; Community antenna television and radio distribution (CAT V) systems; Pre mises-powered broadband co mmunication systems; Radio and television equipment Bonding, 800.100, 800.106(B), 805.93 Within buildings, 805-11 Cable substitutio n , 805.154 Essential electrical systems, 517.33(D ), 517.43( D) Grounding, 800-UI, 805.93 H ybrid power and co mmunications cables, 805.l 79(F) Limited-power circuits, 72.5.121 (A) Listi ng of equipment, 805.18, 805-V Protection, 805-Ill Devices, 805.90 Grounding, 800. IOO, 800.106(A) Mobile homes, ground ing and bonding at, 800.l 06 Primary protectors, 800.100, 800. 106, 805.50, 805.90, 805.170 (A), 830.90 Secondary protecrors, 805.90(D), 805. l 70 (B) Raceways, 800.110, 800.113, 800.154, 800.182, 805.133(A)( l ), 840.170(D) De finition, Art. lOO Unde rground circuits e nte ring buildings, 805.47 Unlisted cables en tering buildings, 805 .48 Communications equipment De finition , Art. JOO Communications service provider De fini tion, 800.2 Communications systems, Sl!e also Communications circuits Abandoned cables, 800.25 Definition, 800.2

NATIONAL ELECTRICAL CODE

Access to electrical equipment, 800.21 Buildings, within, 800.lOO (B), 800-rv Cable marking, 800.179, 800.182 Cable routing assemblies, 800.182 Critical operations power systems, 708.14 Definitions, 800.2 Dwelling unit communications oudets, 800.156 Heald1 care facilities, 517.33( D), 517.43(D), 517- Vl Installation, 800-IV Lightning conductors, 800.53 Listing of equipment, 800.l 13(A), 800.179, 800-V Mechanical execution of work, 800.24 Mobile homes, 800. 106 Multifamily dwellings, 800.113(K) One- and two-fam ily dwellings, 800. 113(L) Overh ead wires and cables, 800.44 Types of cable, 800.179 Community antenna television and radio distribution (CATV) systems, Art. 820; see also Radio and tele\1sion equipment Cables Aeria l e ntra nce, 820.44 Wid1in bui ld ings, 820-V En tering build ings, 820.47, 820.48 Listing, 820.154, 820- Vl Outside, 820.44 Underground, 820.47 Ene rgy limitations, 820.15 Grounding, 820-rv Cables, 820.93, 820.100 Equipment, 820.103 Installation of cables and equipment, 820-V Locations, 820-11 Marking, 820.179 Premises community antenna tele\1sion (CAT V) circuit De finition, 840.2 Premises community antenna television (CAT V) circuits, 840. l 70(F) De finition, 840.2 Protection, 820-Ul, 820.100 Raceways, 820.1 33 Unlisted cables e ntering bu ildings, 820.48

Compressors, refrigeration, Art. 440 Computer rooms, see Information techno logy equipment Concealed Definition, Art. 100 Electrical metallic u.1bing, 358.lO (A) Electrical nonmetallic mbing, 362.!0 (4) Fixed industrial process duct heaters, 425.45 Knob-and-tube wiring, see Knoband-tube wiring Low-voltage su spended ceiling power distribution systems, 393.1 2(4) Metal wireways, 376.10 (4) Nonmetallic extensions, Sl!e Nonmetallic extensio ns Surface metal raceways, 386.12(5) Concentric knockouts, see Knockouts Concrete Boxes Enclosures, 314.23(G) Flush-mounted installations of, 314.20 Cellular concrete floor raceways, Art. 372 Direct-buried cable , conduit, or raceways, cover requiremen ts, Table 300.5 Electrical metallic tubing in, 358.10, 358.42 Electrical no nmetallic mbing in, 362.10 Electrodes encased in, 250.50 Ex., 250.52(A) (3), 250.66( B), 250.68, 250.70 Flexible metal conduit, 348.12(6) Heating cables, installation in concrete floo rs of, 424.44 Hig h density polyemylene conduit in, 353.10 Inte rmediate metal conduit, 342.10, 342.42 (A) Liquidtigh t fl exible metallic conduit, 374.1 8(A) Liquidtig h t fl exible nonmetallic condui t, 356.10(7), 356.42, 374. l8(A) Metal raceways and equipment in, 300.6(A) (3), 300.6(B) Mineral-insulated, metalsh eath ed cable in, 332.10(6)

70-853

NATIONAL ELECTRICAL CODE

Nonmetallic-sheathed cable in, 334.lO(B) (3), 334.12, 334.15(B) Nonmetallic underground conduit with conductors, 3.54.10(2) Rigid metal conduit, 344.10, 344.42(A) Rigid polyvinyl chloride conduit, 352.lO(G) Slabs, raceways under, Table 300.50 Underfloor raceways, 390.10 Underground feeder and branch-circuit cable, type UF, 340.12 (8) Walls, cabinets installed in, 312.3 Conductive surfaces, exposed, 517.11 De finition, 517.2 Conductor fill Audio systems, 640.23(A) Auxiliary gutters, 366.22 Boxes, 314.16(B)(l) , 314.16 (B)(5) Cable trays, 392.22 Cellular concrete floor raceways, 372 .22 Cellular metal floor raceways, 374.22 Control circuits, 517.74(A) Electrical metallic tubing, 358.22 Electrical nonmetallic tubing, 362.2 2 Elevators, 620.32, 620.33 Fixture wire, 402.7 Flexible mera l conduit, 348.22 Flexible metallic tubing, 360.22 General installations, 300.17 HazardotL~ (classified) locations, sealing fi ttings, 501.15(C) (6), 505.16(D)(5) High density polyerh ylene conduit, 353.22 Intermediate metal conduit, 342.22 Liquidtight flexible metal conduit, 350.22 Liquidtight flexible nonmetallic conduit, 356.22 Maximum permitted, 300.17 Nonmetallic underground conduit with conductors, 354. IOO(D) Outlet boxes, etc., 3 14.16 Re inforcing t11e rmosetting resin conduit, 355.22 Remote co ntrol circuits, 725.51 Rigid metal conduit, 344.22

70-854

Rigid polyvinyl chloride conduit, 352.22 Signs, 600.31 (C) Strut-type channel raceway, 384.22 Surface raceways, 386.22, 388.22 Theaters, 520.6 Underfloor raceways, 390.22 Wireways, 376.22, 378 .22 Conductors, see also Cords, flexible; Fixture wires Aluminum, 250.120( B) Ampacities, Table 31 l.60(C) (68), Table 31 1.60(C) (70), Table 31 l.60(C) (72), Table 31 l.60(C) (74), Table 31 l.60(C) (76), Table 31 l.60(C) (78), Table 311.60(C) (80 ), Table 31 l.60(C) (82), Table 311.60(C) (84 ), Table 311.60(C) (86) Pro perties of, Chap. 9, Table 8 Ampacities, 310.14 through 310.21, Tables 31 l.60(C) (67) through 31 I.60(C) (86), Annex B, Tables B. 2(1) t11rough B.2(10) Amusement attractions, 522.20 through 522.24 Applications and insulations rared 600 volts, Table 3 10.4(A) Armored cable, Type AC, see Armored cable (Type AC) Bare, see Bare conductors Be nding radius, 300.34 Bonding, see Bonding conductors Boxes and fittings, junction, 314.16, 314.17 Branch circuits, Art. 210. See also Branch circuits Bundled, in theaters, etc. De finition, 520.2 Buried, 310. I O( E) Busways, see Busways Cabinets and cutout boxes, 312.5 through 312.7 Cable bus, see Cable bus Calculations, examples, Annex D Capacitors, 460.8 Cellular concrete floor raceways, see Cellular co ncrete floor raceways Cellular metal floor raceways, see Cellular me tal floor raceways Circuit Communica tions, Art. 800

Control, heal th care facilities, 517.74 Fire a larm, An. 760 Less than 50 volts, An. 720 Ove r 1000 volts, Art. 490 Signal, remote-control, powerlimired , Art. 725 Combinations, Chap. 9, Table I Communications circuits, 800-11 Concealed knob-and-tube, see Knob-and-tube wiring Conduit or tubing, number in, 342.22, 344.22, 348.22, 3.50.22, 352.22, 353.22, 354.22 , 356.22, 358.22, 360.22 , 362.22, Chap. 9 Tables, Annex C Cooling of electric equipment, 11O.l 3(B) Copper, 110.5, 505.18 (A), 760.49(C) Ampacities, Table 311.60(C) (67), Table 31 l.60(C) (69), Table 31 l.60(C) (71 ), Table 31 l.60(C) (73), Table 31 l.60(C) (75), Table 31 l.60(C) (77), Table 31 l.60(C) (79), Table 31 l.60(C) (81 ), Table 3 1 l.60(C) (83), Table 31 l.60(C) (85), Tables B.2(1) t11rough B.2(10) Properties, Chap. 9, Table 8 Copper-clad aluminum Definition, An. 100 Equipme nt-grounding conductors, 250.120 (B) Cords, flexible, see Cords, flexible Corrosive conditions, see Corrosive conditions Covered De finition, Art. 100 Crane and hoists, 610-11, 610-111, 610.41 Damp locations, 310.IO(B) De finitions, An. 100 Deflection of Auxiliary gutters, 366.58(A) Cabinets and cutout boxes, 3 12.6 Different systems, 300. 3(C), 72.5.48 Dime nsions of, Chap. 9, Table 4 Dry locations, 310.IO (A) and (B) Electrical metallic tubing, see Electrical metallic tubing Electrical nonmetallic tubing, see Elec trical nonmetallic tubing

Elevators, dumbwaiters, escalators, etc., 620- 11 t11rough 620-IV Enclosure, grounding, 250-N Gro unding electrode conductors, 2.50.64(D), 250.64(E) Equipment grounding, see Equipment grounding conductors Feeder; Art. 215 Fire alarm systems, 760.3, 760.48, 760.49, 760.130 Fire pumps, 695.6 Fixed resistance and electrode incl ustrial process heating equipment, supply conductors, 425.11, 425.22 (0 ), 425.22(E) Fixrure wires, Arr. 402 Gages (AWG), general provisions, I L0.6 General wiring, An. 310 Gene rato rs, size, 445.13 Grounded, see Grounded conductors Gro unded power systems in anesthetizing locations, 5 17.63 Grounding, see Grounding conductors Grounding electrode, see Grounding e lectrode conductors Grouped, 520.54 (C), 620.21 (A), 620.44, 640.8, 650.6, 690.31 (B) (2) Definition , 520.2 Ide ntification, 3 10.8, 311.14, 311.1 6, 4 10.69 Induction and d ielectric heating equipment, ampacity of supply, 665.10 Industrial control panels, 409.20 Installation , 310-111 Otl1er system s, witl1, 300.8 Insulated, Art. 310 At bushings, 4 AWG and larger, 300.4 (G), 312.6(C) Construction and application, 311.10 Definition , Art. 100, 396.2 Elevators, dumbwaiters, escalators, etc., 620.II Fire alarm systems, 760.49(B) Fixtures, 410.52, 410.117 (A) Grounded conductors, 200.2 (A), 551.54(C), 552.55(C)

NATIONAL ELECTRICAL CODE

2020 Edi tion

INDEX

Hazardous (classified) locations, 501.20, 505.l 8(B) Ide ntification, 3 11.14, 410.69 Line-ry pe fire detectors, 760.179(.l) Low-voltage suspended ceiling power distribution systems, 393.14 (B) Motion picrure pr~jectors, 540.14 Outside branch circuits and feeders, 225.4 Park trailers, 552 .55 ( C) Re inforced thermosetting resin conduit, 355.lO (I ) Service conductors, 230.22, 230.30(A), 230.41 Splices and joints, l 10.14(B), 400.13, 530.1 2( B), 590.4(G) Switchboards, 408.19 Theaters, 520.42 Interconnected electric power production sources, 705.11 ( B) Intrinsically safe, 504.30, 504.50 Length in boxes, 300.14 Length in surge protective de\~ces, 242.28 Lightning rod s, spacing from , 250.106 l N No. 2, 800.53 Liquidtight flexible metal conduit, see Liquidtight flexible metal conduit Liquidtigh t flexible nonmetallic conduit, see Liquidtight flexible nonmetallic conduit Low-voltage susp e nded ceiling power distribution systems, 393.104 Marking, 311.16 Mate rial, 311.1 2 (B) Metal-dad cable, see Metal-clad cable Metal enclosures, spacing from lightning rods, 250.106 IN No. 2 Metal wireways, 376.56(B) (5) Mineral-insulated metalsheathed cable, see Mineral-insulated metalsheathed cable (Type MJ)

Minimum size, 230.31 , 230.42, 311.12 (A), 517.74( B), 620.12 , 650.6(A), 660.9, 725.49 (A), 760.49(A), 760.142, 810.17 , 810.53

2020 Edition

Modular d ata centers, supply conductors, 646.6, 646.9(D) Motion picture projectors, 540.1 3 Motor circuits, 430.6, 430-11 Multioutlet assembly, see Multioutlet assembly Multiple, 250.102(C), 250.l22(F), 300.5( 1) Ex. 1, 300.20, 310.lO (G), 392.20(C), 520.27(A) (2), 620.12(A) (l) Neuu-al, see Neutral Nonmetallic extensions, see Nonmetallic extensions Nonmetallic sheathed cable, Types NM, NMC, and NMS, see Nonmetallicsheathed cable (Types NM, NMC, and NMS) Number of, in, see Conductor fill Organs, 650.6, 650.7 Outdoor overhead conductors over 1000 volts, Art. 399 Outlet boxes, temperature limits, 410.21 Outside wiring, Art. 22.5 Overcurre nt protection, 240.4 Cablebus conductors, 370.23 Fixed resistance and electrode industrial process heati ng equipment, 425.72(E), 425.72(F) Grounded co nductors, 230.90( B), 240.22 Service-en trance co nductors, 230.90, 230.91, 230.208 O verhead service, see O verhead se r~ce conductors Over 1000 volts, Art. 490 Outdoor overhead co nductors, Art. 399 Pa ralleled, 250.30(A)(3), 250.102(C), 250. 122(F), 250.l86(A)(2) , 250.186( B)(2), 300.3( B) (l ), 300 .5(1) Ex. l, 300.20, 310.lO(G), 366.20, 376.20, 392.20(C), 520.27(A) (2), 620.l2(A)( l ); see also Flat cable assemblies (Type FC) Pe ndant fix tu res, 4 10.54 Prope rties ot: Chap. 9, Table 8 Raceways, numbe r of conductors in, see Conductor fill Radio and televisio n equipme nt and antenna syste ms, 810. 13,

NATIONAL ELECTRICAL CODE

810.16(A), 8 10.17, An. 820 Railway, power and ligh t from, 110.19 Recreational vehicle site feeder circuit, 551.73, 5.51.80 Definition, 551 .2 Remote-control circuits, Art. 725 Rigid metal conduit, see Rigid metal conduit Same circuit, 300.5(1) Selection of, examples, Annex D Service, see also O verhead service conductors; Ser~ceen trance cable (Types SE and USE); Ser~ce­ e ntrance conductors De finitions, An. 100 Unde rground service, 300.5( D) (3) Setvice-en trance, see Serviceentrance conductors Signal circuits, Art. 725 , An. 760 Signs and outline lighting, 600.31, 600.32, 600.33 Single, 392.lO(B)(l ), 392.20(D), 392.22(B), 392.80 Sizes, 110.6, 540.13, 810.16(A), Table 810.16(A), 8 10.17, 810.53, Ch ap. 9, Tables 5 and 5A; see alrn Minimum size Spliced , 230.33, 230.46 Stranded , 3 ll.12 (C), Chap.9, Table 10 Support of; 110.12(C), 300.19 Surface raceway, see Strut-rype channel raceway; Surface metal raceways; Surface nonmetallic raceways Switchboards and panelboards, 408.3(A), 408.19, 520.53 (E), 520.54 Temperature, limitations of, 310.14(A)(3), 338. LO(B) (3) Theaters, portable stage equipment, 520.68 Tunnels, 110.53, 110.54 Underfloor raceway, see Underfloor raceways Underground feeder and branch-circuit cable, see Underground feede r and branch-circuit cable (Type UF) Unde rground se r~ce, 300.5(D)(3) De finition, Art. 100 Ungrounded Disconnection of; 230.70

Flat conductors, nonmetallic extensions, 382.104 (A) Grounding separately derived systems, 250.30(B) Ide ntification, 2 10.5(C), 215.12 (C) L an1pholders, 410.93 Multiple branch circuits, 210.7 O vercurrent protection, 240.15 Services, 230.90(A) Tapped from g rounded system, 210.10 Welders, e lectric An1paciry of supply, 630.11 , 630.3 1 Overcurrent p rotection, 630. 12(B), 630.32(B) Wet locatio ns, 225.4, 310. lO(C) Wireways, seeWireways, metal; Wireways, nonmetallic X-ray equipment, 517-V, 660.6 tl1rough 660.9 Conduit bodies, see also Boxes (outlet, device, pull, a nd j unction) Definition,Art.100 Marking, 314.44 Number of conductors, 3l 4. l 6(C) Over 1000 volts, 314-1\1 Pull and junction box, 314.28 Shon radius, 314.16(C) (3) Support Cable trays, 392.18(G) By reinforcing thermosetting resin conduit, 355.l O(H) By rig id nonmetallic condui t, 352.lO(H) Conduit fill, see also Conductor fill Equipment g rounding conductors, Chap. 9, Note 3 Grounding conductor, 310.15(F) Conduit nipples, Chap. 9, Note 4 Conduits Boxes supporting, 314.23( H) (2) Circuits, physical protection of remote control, 725.31 (B) Conductors, numbe r in, Chap. 9, Table 1, Annex C, Tables C.l through C.13(A) Dime nsions, Ch ap. 9, Table 4 Electrical metallic tubing, see Electrical metallic tubing Electrical nonmetallic tubing, SP£ Electrical nonmetallic tubing Flexible metal, see Flexible metal condui t

70-855

NATIONAL ELECTRICAL CODE

High density polyech ylene conduit (Type HOPE), see High density polyeth ylene conduit (Type HOPE) lntermediace mecal, see Intermediate mecal conduic Liquidtight flexible metal, see Liquidcight flexible metal conduit Liquidtight flexible nonmetallic, see Liquidtight flexible nonmetallic conduit Manufacntred wiring systems, 600.100(2) Mecallic, grounding runs 7.5 m (25 ft), 250.86 Ex.I Number offixcure wires in, 402.7 Outside wiring, 225.10 Rigid metal, see Rigid metal conduit Rigid polyvinyl chloride, see Rigid polyvinyl chloride conduit Connections Aluminum, copper conductors, 110.14 Busways, 368.238 Cellular metal floor raceways tO cabinets and extensions, 37 4. I 8(A) Eleccric vehicle supply equipment, 625.44 Essential elecffical syscems, 517.32, 517.35, 517.43, 517.44 Fixed electric space-heating equipment, 424.45(C), 424.99 (B) (2) Fuel cell systems to othe r circuit~. 692-Vll Grounding conductor, 250-111, 2.50- Vl High-impedance grounded neuffal system, 250.187(C) Integrity of, ll0.12(B) Interconnected power production sources, 705.ll (D) Multiple circuit connec tions, grounding, 250.144 Splices, 110.14(B) Switches, 404.2 Temperature limitations, l 10.14(C), 110.40 Terminals, 110.14(A), 110.14(0 ) X-ray installations, 517. 71 Connectors Armored cable, 320.40

70-856

Boxes, 314.17 Breakollt assembly, 520.68(A) (6) Definition, 520.2 Cabinets and cutout boxes, 312.5 (C) Cable Definition, 324.2 Theate r, 520.67 Co nnector mip, 520.44, .520.46 Definition, 520.2 Elecu'ical metallic tubing, 3.58 .42 Elecffic vehicle, 625.17(B) , 625.50 Definition, 625.2 Flexible metal conduic, 348.42 lntercell, 480.4(B) Definition, 480.2 Inte rmediate metal conduic, 342.42 lnte nier, 480.4 ( B) Definition, 480.2 Liquidtight flexible mecal co nduic, 350.42 Liquidtight flexible nonmetallic conduit, 356.42 Low-voltage suspe nded ceiling power discribution systems, 393.40(A) Definitions, 393.2 Pressure (solderless), 250.8(3), 250.70 Definition, Art 100 Rigid metal conduit, 344.42 Single-pole separable, 520.53(C), 520..54(1), 525.22( 0 ), 530.22 Definition, Art 100 Solar photovoltaic syscems, 690.32, 690.33 Constant-voltage generators, Art. 445 Overcurren t protection for, 445.12 (A) Construction, closed, .545.4(B), 545.9( B) Definition, 545.2 Construction, types of, Annex E Construction sites Assured equipme nt grounding co nductor program, 590 .6(B) (2) Extension cord sets, 590.6(A), 590.6(B) (2) Ground-fault protection, 590.6 Container, storage battery De finition, 480.2 Continuity Elecffical Cable ffays, 392.60(A)

Equipme nt grounding conduccors, 250.124 Grounded conductors, 200.2 (B) Gutcers, auxiliary, 366.lOO (A) Metal raceways and cables, 250.92(B), 250.96, 250.97, 300.10 Wireways, 376. lOO(A) Grounding, metal boxes, grounding-type receptacles, 250.148 Mechanical Gutce rs, auxiliary, 366. lOO (A) Raceways and cables, 300.IO, 300.12 Conduccors, 300.1 3 Grounded conductor of multiwire circuits, 300.13(B) Wireways, 376.lOO(A) Continuous duty Definition, Art. 100 Motors, see Motors, Continuous duty Continuous industrial processes Coordination, elecffical system, 240.12 Ground-fault protection, 230.95 E.x. Orderly shutdown, 430.44 Power loss hazard, 240.4(A) Continuous load Applications, 210.19 (A), 210.20(A), 215.2(A) De finition, An. 100 Control, see also Hazardous (classified) locations De finition, 750.2 Remoce Circuits, see Remoce-conffo l, signaling, and powerlimi ted circuits Induction and dielectric hea ting equipme nt, 665.7 X-ray equipment, 5 17-V, 660-11 Control circuits, 2 30 .82 (7), 430-Vl Amusement accractions, 522- 11, 522- 111 Definition, Art. 100 Control drawing, 504.IO (A) De finition, Art. 100 Controllers, see also Hazardous (classified) locations Agriculntral buildings, 547.6 Air-conditioning a nd refrigerating equipment, 440.5, 440-V Cases, grounding, 250.112( 0 )

Charge controllers Definition , Arc. 100, 694.2 Energy storage systems, 706.33 Solar photovoltaic syscems, 690.72 Definition, An. 100 Dive rsion load controlle rs, 694.7(C) De finition , 694.2 Enclosures, grounding, 250.112 (0 ) Fire pumps, 695. 12, 695.14(0), 695. 14(E) Motion, 6I0.5l (B) , Fig. 09, Fig. 010 Definition, 620.2 Moto r; see Motor con trollers Ope ration, 620.22(A), 620.51 (C) (1), Annex D, Ex. 09, Fig. 09, Fig. 01 0 De finition , 620.2 Ratings, 430.83 Resistors and reactors, see Resisto rs and reactors Control panels, see Industrial control pane ls Control room Branch circuits, lighting and recepracles, 620.23 De finition , 620.2 Wiring, 620.21 (A) (3), 620.37 Control space Branch circuits, lighting and recepcacles, 620.23 Definition , 620.2 Wiring, 620.21 (A) (3), 620.37 Control system De finition , 620.2 Convenience outlets, see Receptacles Conversion table, AC conductor resistances and reactances, Chap. 9, Table 9 Converters, see also DC-to-DC conveners; Elecffonic power conve ners; Phase converters Charger power; 625. 102 Definition , 625.2 Definition , 551.2 Voltage, 551 .20, 552.20 Definition, 551.2 Cooking unit, countermounted, see also Ovens, wall-mounted; Ranges Branch circuits, 210.19(A) (3), 2l0.23(C), 220.55 De finition , An. 100 Feeders, calculation of load, 220.82 (B) (3)

NATIONAL ELECTRICAL CODE

2020 Edi tion

INDEX

Grounding, 250.140 Cooling of equipment, 110.1 3(B ) Coordination, electrical systems, 240.12 Feeders, 240.lOO(C), 517.17(B) O vercurre nt protective devices Critical operations power systems, 708 .54 Health care facilities, 517.3 l (G) Information technology equipmenL, 645.27 Legally required standby systems, 701.32 Selective, 620.62, 645.27, 695.3(C) (3), 700.1 O(B), 700.32, 701.32 Definition, Art. 100 Copper-clad aluminum conductors Defini tion, An. 100 Equipme nt-grounding conductors, 250.120(B) Copper conductors, see Conductors, copper Cord connectors, 626.25(B)(5); see also Receptacles, cord connecto rs, and auachment p lugs (caps) Definition, An. 100, 626.2 Cords, see also Hazardous (classified) locations Audio sig nal processing, amplification, and re production equipment power supply cords, 640.21, 640.42 Electric-discharge Iumina ires, 410.62(C) (1) Electrified truck parking space power-supply, 626.25(B), 626.32 Flexible, An. 400, 422.16, 422.43 Air conditioner, 440.64 Ampacities, Tables 400.5 (A) ( l ) through 400.5(A) (3) Anesthetizing locations, 517.61 (A) Audio signal processing, amplification, and re produc tion equipment, 640.21, 640.42, 640.45 Bending radii, minimum, 400.34 Construction specifications, 400-11 Electrified truck parking space supply equipment, 626.25(B)(2 ), 626.32(C) Emergency systems, 700.12 (1)(2)

2020 Edition

Eq uipme nL grounding conductors Identification, 400.23 Over 600 volts, 400.31 (B), 400.32, 400.33 Size of, 250.122(£) Fittings, 400.35 Hazardous (classified) locations, 505.17, 506.17 Identified conductors within, 200.6(C), 250.119(C), 400.22, 400.23 Insulation, Table 400.4, 400.2l (B) Interconnected electric power production sources, 705.25(B) Labels, 400.20 Lampholde rs, insulating bushings, 410.62(A) Manufactured wiring systems, 604.lOO(A) (3) Marking, 400.6 Modular data cente r equipment e nclosures, 646.9 Motion picture projectors, 540.15 Office htrnishing, 605.9(A) Oudets Covers, 3 l4.25 (C) Required, 210.50(B) Overcurrent protection, 240.5, 400.16 Over 600 volts, 400-III Powe r-limited and signal circuits, remoteco ntrol, 725.49(A) Pull at joints and terminals, 400.14 Repair of, hard service, 400.1 3 Showcases, wall cases, 410.59 Solar photovoltaic signs, 600.34(C) Solar photovoltaic systems, 690.31 (C) (4) Splices and taps, 400.13, 400.36, 530.12 Co nstruction sites, 590.4(G) Stage equipment, portable, 520.68(A) ( l ) Swimming pools, fountains, a nd similar installations, 680.8, 680.21 (A) (3), 680.23(B) (3), 680.35(A), 680.42(A), 680.55(B), 680.56 Types, 400.4, Table 400.4 Uses not permitted, 400.12 Uses permitted, 400.10

NATIONAL ELECTRICAL CODE

Wind electric systems, 694.30 (B) Heater, Table 400.4, 422.43(A) Information power-supply cord, 645 .5( B) Mobile home powe1~suppl y cord, 550.10 Office furnishings power-supply cord, 605 .9(A) Park trailer power-supply cord, 552.43(B), 5.52.44 Recreational vehicle powersupply cord, 551.31, 551.46 Solar photovoltaic signs, 600.34(C) Submersible or floating equipment, for bodies of water, 682. 14 Tinsel Overcurrent protection, 400.16 Types, Table 400.4 Vehicle supply equipment power-supply cord, 625.17(A), 625.l 7(C) De finition, 625.2 Cord sets, see Exte nsion cord sets Correction factors, ambient temperature, 310. 15(B), Table 310.1 5(B) (l ), Table 310.15(B) (2), Table 31 l.60(D ) (4) Corrosion protection, see Protection, corrosion Corrosive conditions Agriculcural buildings, wiring in, 547.5(C) (3) Armored cable, 320.12 (4) Bushings, 430.13 lN Cablebtts, 370.10(3) Conductors and conductor insulation, 300. 6, 310.lO(F) , 505.1 8( B) High density polyethylene conduit, 353.10(2) Rigid polyvinyl chloride conduit, 352.lO(B) Deteriorating agents, I IO. I I Electrical nonmetallic tubing, 362.10 (3) Fire alarm systems, 760.3( D) Flat cable assemblies, 322. l 2 ( L) Flat conductor cable, 324.12(2), 324.101 Low-voltage s uspended ceiling power distribution systems, 39 3.1 2 (2) Luminaires installed in, 410.lO( B) Metal wireways, 376.12 (2)

Mine ral-insulated, metalsheathed cable, 332.10(10) Nonmetallic-sheath ed cable, 334.lO(B) ( 1), 334.l2 (B) ( 1) Nonmetallic wireways, 378. l 0 (2) Open wiring on insulators, 398.15 (B) Reinforcing thermosetting resin conduit, 355.10 Surface metal raceways, 386.12 (3) Underground feede r and branch-circuit cable, 340.10(3) Corrosive environment, 680.7, 680.14, 680.2 1 (A)(l ), 680.23( F)( I ), 680.25(A) De finition , 680.2 Countertops, outlets, 210.52(A) (4), 210.52(C), 406.5(E) Couplings Electrical metallic tubing, 358.42 Fire resistive system, 728.5 (C) Flexible metal conduit, 348.42 Inte rmediate metal conduit, 342.42 Liquidtiglu fl exible metal condui t, 350.42 Liquidtig ht flexible nonmetallic condui t, 356.42 Rigid metal conduit, 344.42 Running threads al, 342.42 (B), 344.42 (B) Threaded and d1readless, 250.92(B) Cove lighting, space for, 410.18 Covers Auxiliary guuers, 366.lOO (D) Boxes and fittin gs, 314.25, 314.28(C), 314.41 , 314.42, 3 14.72 (£ ) Cable, 650.6(D) Cable trays, 392.18(C) Faceplates, see Faceplates Luminaires fixmres, outlet boxes for, 410.22, 410.23 Pool cover, e lectrically operated, 680.27 (B) Definition , 680.2 Strut-type c hanne l raceways, 384.lOO (C) Wireways, 376.2, 376.56 (B)(4), 376.lOO(D), 378.2 Cranes, An. 610; see also Hoists Bo nding, 610-Vll Conductors, 610-III Control, 610-VI Definition, 555.2

70-857

NATIONAL E LECTRICAL CODE

Disconnecting means, 430.112 Ex., 610--rv Electrolytic cells, 668. 32 Flexib le cords, 400. lO(A) (5) Grounding, 250.22(1), 2.50.112(E) , 250.116(1), 610-VII Ha za rdotL~ (classified) locations, 503.155, 610.3(A) Marina~ and boatyards, 555.8 Motors and controllers, disconnecting means, 430. l l 2 Ex. Nameplates, 610.14(G) O vercurrent protection, 610--V, 610.53 Wiring, 610--11 Cr itical bran ch , 517.25, 517.29 IN, 517.31, 517.34 Definition, 517.2 Essential electrical systems, 517 .35 Critical care space, 517.19, 517.29(B), 5 17.34(A), 517.40(B), 517.45(C) Definition, 517.2 Nursing homes and limited care facilities, 517.40 I N No. l Critical operations data system, 645.1 O(B) Definition, 645.2 Critical operations power systems, Art. 708, Annex F Availability and reliabi li ty fo1; Annex F-1 Circuit wiring and equipment, 708-11 Commissioning, 708.8 Definition, 708.2 Definitions, 708.2 Developme nt and implementation of functional performance tests (FPTs), Annex F- 11 Emergency operations p lan, 708.64 Grounding, 708.20 (C) O vercurrent protec tion, 708-IV Physical securi ty, 708.5 Power sources and connection, 708-lll Risk assessment, 708.4 System performance and analysis, 708-V Testing and maintenance, 708.6, 708.8 Cross sectional areas Conductors, Chap. 9, Tables 5 through 8 Conduits, Chap. 9, Table 4

70-858

Current-carrying cap acities, see An1pacities Current-limiting devices, see also Circuit breakers; Fuses Definition, 240.2 Curtain machines, theaters, 520.48 Cutout b ases, see Fuseholders Cutout boxes, see also Cabinets, cutout boxes, and meter socket enclosures Definition, Art. 100 Cutting tables, motion pic ture, 530-IV -D-

Dampers (flue), control Critical operations power systems, 708.20(F)(4) Fixed stage equipment, smoke ventilator control, 520.49 Transformer vau lts, ventilating openings, 450.45(E) Damp or wet locations, l l0.11. See also Wet locations Agricultural buildings, 547.5(C)(2) Armored cable, 320.12 Boxes and fittings, 314.15 Busways, 368. l2(D) Cabinets and cutout boxes, 312.2 Cablebus, 370. 10 (3) Conductors, types, 310. lO( B), 310.lO(C) Definition, Art. 100 Electrical nonmetallic tubing, 362.10(4) , 362.10(7) Electric signs and outline lighting, 600.lO(C), 600.42(G), 600.42(H)(2) Fire alarm systems, 760.3(D) Fixed electric space-h eating equipment, 424. l2(B) Fixed resistance and electrode industrial process heating equipment, supply conductors, 425. l2(B) Flat conductor cable, 324.lO(E), 324.12( I ) Lampholders, 410.96 Low-vollage suspended ceiling power distribution systems, 393.12 ( 1) Luminaires, 410.JO(A) Metal-clad cable, 330. IO(A) Mineral-insulated, metalsheathed cable, 332.10(3) Nonmetallic-sheathed cable, 334.IO(B) (1), 334.12(B)(4)

Ope n wiring, 398.15(B) Overcurrent protection, enclosure, 240.32 Panelboards, 408.37 Receptacles, 210.S(A)(ll), 406.9 Reinforcing thermosetting resin conduit, 35.5.lO(D), 355.IO(E) Rigid polyvinyl chloride conduit, 35.5.lO(D), 355.1 O(E) Switchboards, 408.l 6 Switches, 404.4 Dance halls, Art. 518 Data centers, mo dular , see Modular data cente rs Data processing systems, see Information technology equipment DC combiners, 600.34(A) , 690.4 (B) De finition, 690.2 DC systems, 250--Vlll; see also Direct current microgrid systems Branch circuits, identification of, 210.5(C)(2) Grounding, 250.162, 250.164 Lum inaires, installation of, 410.1 34 Solar photovoltaic systems, see Solar photovoltaic systems DC-to-DC converters, IN Fig. 690.1(a),690.4(B), 690.7 (B) , 690.8(A)(J), 690.15, 690.41 (B), 706.30(A) (5), 706.33(C) Definitions, Art. 100, 690.2 Dea d ends Busways, 368.58 Cablebus, 370.42(2) Flat cable assemblies, 322.40(A) Wireways, 376.58, 378.58 Dead front, ll0.26(A) ( l) De finition, Art. 100, 551.2 Instrume n ts, meters, and relays on, 250.l 74( B) Park trailers, 552.45(C) Recreational vehicles, 551.45 (C) Working spaces about, l 10.26 (A)( l ) Decks, recep tacles for, 210.52 (E) (3) Definitions, Art. l 00 Deflection of conductors Auxiliary gutters, 366.58(A) Cab inets and cutou t boxes, 312.6 Deicing installations, see Fixed outdoor e lectric deicing

and snow-melting equipment Delta breakers, 408.36(C) Delta-connected Grounding separate ly derived systems, 250.30 (A) (3) Identifying high-leg, 3-phase supply, 4-wire, 110 .15, 230.56, 408.3(E) ( l ), 408.3 (F), 409.102 Demand factor, see also Loads Definition ,Art.100 Dental office (medical office) De finition , 517.2 Designated critical op erations area , see also Critical operations power systems Definition, 708.2 Detached buildings, oil-insulated transfor mers in, 450.26 Ex. 5 Deteriorating agents, l l 0.11 Device, see also Receptacles; Switches Definition, Art. 100 Device or equipmen t fill for boxes, 314.16(B)(4) Diagnostic equipment, 5 I 7.73(A) Diagrams Adjustable speed drive control, Fig . D.10 Autotransformer overcurrent protection, Fig. 4.50.4 Cable installation dimensions, underground, Figs. B.2(1) through B.2(4) for use with Tables B. 2 (5) through B.2 (10) Cable substimtion hierarchy Communications systems, Fig. 805. 1.54 Community antenna T V and radio distribution systems, Fig. 820. 154 Optical fibe r cables, Fig. 770.1 54 Remote control, signaling, and power limited circuits, Fig. 725.154 (A) Communications system, bonding conductor in, Fig. IN 800.lOO(B) ( I), Fig. IN 800. l OO( B) (2) Elevators, dumbwaiters, escalators, etc. Contro l system, Fig. 620.2 Single li ne diagram, Fig. 620. 13 Feeders, 2 15.5 Generator fi eld control, Fig. D.9

NATIONAL ELECTRICAL CODE

2020 Edition

INDEX

Hazardous (classified ) locations adjacent to dispensers, Fig. 514.3, Fig. 514.3( B) Luminaires, closet st0rage space, Fig. 410.2 Marine term ina l handling flammable liquids, Fig. 515 .3 Mobile homes, receptacle and attachment plug, Fig. 550.lO(C) Motor feeder and branch circuits, Fig. 430.1 Park trailers, receptacles and attachment p lugs, Fig. 552 .44 (C) ( I ) Recreational vehicles, receptacles and attachment plugs, Fig. 551.46(C) ( 1) Remote control, signaling, and power limited c ircuits, Class 2 and 3 circuits, IN Fig. 725.121 Services, Fig. 230.l Solar photovoltaic systems, identification of compo ne nts, Fig. 690.l (a), Fig. 690.1 (b) Spray application, dipping, coating, and printing, Fig. 516.4, Fig. 516.5 (D)(l), Fig. 516.5(D) (2), Fig. 516.5(D)(4), Fig. 516.5( D) (5), Fig. 516.18, Figs. 516.29(a) through (d) Swimming pools, clearance from pool strucru res, Fig. 680.9(A) Dielectric heating, see also Induction and dielectric heating equipment Definition, 665.2 Different systems, conductors in same enclosure, 300.3(C), 725.48, 725.1 36 (B), 760.48, 760.1 36, 805.47(A), 805.1 33(A), 810.18(C), 820.133(A) Dimensions Conductors, C hap. 9, Tables 5 through 8 Conduits and tubing, C hap. 9, Table 4 Dimmers Emergency lighting circuits, 700.23 Solid-state-type, 520.25(C) De finition, 520.2 Stage switchboard, 520.25

2020 Edition

Switches, 404.9(B) , 404.14(E); S(;?alsoSnap switches Dip tanks, An. 516 Direct burial Ampacities, modification of, 310.16 CATV coaxial cables, 820.47(B) Corrosion protection Aluminum metal equipment, 300.6(B) Ferrous metal equipment, 300.6(A) (3) Electrical nonmetallic tubing, 362.12(4) Flexible metallic mbing, 360.12(4) Grounding conductor connection, 250.68(A) Ex. 1, 250.70 High density polyethylene conduit, Table 300.50, 353.10(4) Integrated gas sp acer cable, 326.10 Intermediate metal co nduit, Table 300.5, Table 300.50 Liquidtight flexible metal co nduit, 350.10( 3), 350.120 Liquidtight flexible nonmecallic conduic, 356.10( 4), 356.10(7) Medium voltage cable, 3 11.36 Metal-dad cable, 330.lO(A) (5), 330.12(2) Nonmetallic underground co nduit wich conductors, 354.10( I ) Optical fibe r cables, 770.47(B) Ove r 1000 volts, 300.50 Pre mises-powered broadband communication, optical fiber cables for, 840.47 (A) (2) Reinforced thermosetting resin conduit, Table 300.50 Rigid metal conduit, Table 300.5, Table 300.50, 344. lO(A) (2), 344.lO (B) Rigid polyvinyl chloride co nduit, Table 300.50, 352.lO(G) Bulk storage p lants, 515.8 Motor fuel dispen sing facilities, 514.8 Ex. 2 Underground feeder and branch-circuit cable, 340. 10 ( 1) Underground service cable, 230.30(A) Ex., Table 300.5, 3 10.lO(E)

NATIONAL ELECTRICAL CODE

Underground service-entrance conductors, 230.41 Ex. Direct current micro grid systems, Art 712 Circuits, 712-11 Definitions, 712.2 Disconnec ting means, 712-lll Fuel cell system installation, 692.4(B) (2) Marking, 712- V Primary DC source Definition, 712.2 Directory, 712.10 Protection, 712-Vl Systems over 1000 volts, 7 12- Vll Wind electric systems, 694.50 (B) Wiring methods, 712-1\1 Disconnecting means, see also O vercurrent protec tion Agricultural bui ld ings, 547.9 Air-conditioning and refrigerating equipment, 440-11 , 440.63 Appliances, 422-III Branch circuits, multiwire, 210.4( B) Capacitors, 460.8(C) Carnivals, circuses, fairs, and similar events, 525.21 (A) Cranes, 4 30.112 Ex., 610-IV De finitions, Art 100, 551.2 Direct current microgrid systems, 712-Ill Electric deicing, snow-melting equipment, 426.50 Electric p ipeline, vessel heating equipment, 427.55 Electric space heating equipment, 424-III Electric vehicle charging system equipment, 625.43 Electrolytic cells, 668.13 Electroplating systems, 669.8 Elevators, 620- VI, 620.91 (C) Eme rgency systems, 700.15(D) Energy storage systems, 706--11 Fire pumps, 695.4( B) Fixed e lectric heating equipme nt for pipelines and vessels, 427 .55 Fixed outdoor electric deicing and s now-melting equipment, 426.50 Fixed resiscance and e lectrode industrial process heating equipment, supply conductors, 425.19, 425.65

Fue l cell systems, see Fuel cell systems Fuses, 240.40 Generato rs, 445.1 8 Health care facilities, 517.l 7 (B), 517. l 7(C), 517.72 Identification, 110.22, 230.70(B), 620.5l(D) Induction and dielectric heating equipment, 665.12 Industrial control panels, 409.30 Industrial machinery, 670.4(B) Information technology equipment, 645.4(1), 645.10 Interconnected electric power production sources, 705 .12 (A), 705.20 Irrigation machines, 675.8 Legally required standby systems, 701.1 2(G) Lockable, 110.25 Low-voltage suspended ceiling power d istribution systems, 393.21 Lmninaires, 410. 130 (G), 410. 14 l (A) Marinas and boatyards, 555.36 Mobile homes, 5.50.11 Moto rs and controllers, 430.75, 430.95, 430- IX, 430. 128, 430.227 Naturally and artificially made bodies of water, elecu"ical equipment for, 682. 14 Outside branch circuits and feeders, 225 .31, 225.51, 225.52 O ver 1000 volts, 240-IV, 240.67(B), 240.83( D), 368.239 Mobile and portable equipment, 490.5 l (D) Parking space, 626.22( D), 626.24(C), 626.31 Definition, 626.2 Phase conveners, 455 .8, 455.20 Pools, spas, and hot tubs, 680.1 3, 680.57(D) Portable equipment, 517. l 7 (C) Receptacles, cord connectors and attachment p lugs (caps), 422.33, 440.63 Recreatio nal vehicle parks, 55 l.77(B) Rec reational vehicles, 55 1.45(C) Reloca.cable su-uctures, 545.24(A) Sensitive electronic equipment, lighting equipme nt, 647.8(A)

70-859

NATIONAL ELECTRICAL CODE

Separate building on same premises, 2.50.32(D) Services, 230- VI, 2.50.64(D) Connections, ahead ot: 230.82 Emergency, 230.85 Over 1000 volts, 22551, 225.52, 230.205, 230.206 Shore power connections, 555.36 Signs and oucline lighting, 600.6, 680.57(D) Solar photovol taic signs, 600.34(E), 691.9 Solar photovoltaic systems, 690-lll, 690.53, 690.54, 690.56 Stage switchboard, 520.27(A) (3) Standby systems, optional, 702.12 St.0rage batteries, 480.7 Switching devices, over 1000 volts, 240.83(D), 249.67(B), 368.239 Definition, Art. 100 Temporary circuits, 590.4 (E) Transformers, 450.14 Tunnels, 110.58 Welders, 630.13, 630.33 Wind electric systems, 694-111 X-ray equipment, 517.72, 660.5, 660.24 Discontinued ou tie ts, see 0 utlets, discontinued Dissimilar metals, see Metals, dissimilar Distribution panelboards, see Panelboards Distribution point, 54 7.9 Definition, 547.2 Diversion ch arge controller, 706.33(B) Definition, 694.2, 706.2 Diversion load, 694.7(C) Definition, 694.2 Diversion load controller, 694.7(C) Definition, 694.2 Docking facilities, commercial and noncommercial, see Marinas, boatyards, floating buildings, and docking facilities Doors Automatic, 517.33( 1-l) Transformer vaults, 450.43 Dormitory units Arc-fault circuit-i nterrupter protection, 210.12(B), 210.12(D) Definitions, Art. 100 Ouclet~, 210.60

70-860

Double insulated Appliances and tools, 250.114 Ex.,422.16(B)(I) Ex., 422.16(B) (2) Ex. Pool pumps, 680.2l(B), 680.31 Double locknuts, see Locknuts, double, required D rainage Busways, 368.236 Equipment, 501.15( F), 505.16(E) Oil-insulated outdoor transformers, 450.27 Raceways, 225.22, 230.53 Transformer vaults, 450.46 Dressing rooms Motion picture studios, 530-lll Theaters, 520- VI Drip loops Conduct0rs entering buildings, 230.24(B)(l), 230.52, 230.54(F) , 398.15( B) Service heads, 230.54( F) Driveways Clearance of conductors, 225.18 Overhead service conductors, 230.24(B) Drop Service Connections, service head, 230.54 Definition, Art 100 Voltage and volts Branch circuits, 21O.l9(A) IN No.3 Conductors, 310.14(A) (1) IN No. 1 Sensitive e lectronic equipment, 647.4( D) Dryers, clothes, see Clothes dryers D ry location, 110.11; see also Damp or wet locations Armored cable, 320.10(3) Conductors, types, 310.lO(A), 310. lO(B) Definition, Art. 100 Electrical nonmetallic tubing, 362.10(4) Electric signs and outline lighting, 600.42(1-l)(l) Portable or mobile, 600.lO( D) Flexible metallic tubing, 360.10(1) Low-voltage suspended ceiling power distribution systems, 393.10(2) Medium voltage cable, 311.32(1) Metal-clad cable, 330.1 O(A) ( 10)

Mineral-insulated, metalsheathed cable, 332.10(3) Nonmetallic extensions, 382.lO(B) Nonmetallic-sheacl1ed cable, 334.10 Open wiring, 398.l.5(A) Reinforcing thermosetting resin conduit, 355.l O(E) Rigid polyvinyl chloride conduit, 352.lO(E) Surface raceways, 386.10(1), 388.10(1) Switchboards, 408.20 Underground feeder and branch-circuit cable, 340.10(3) Dry-type transformers, 450.1 Ex. 2, 450.8(B), 450.21, 450.22 Dual-voltage motor, locked..-otor rating, 430.7(B)(3) Duct heaters, installation of, 424- Vl Ducts Bonding, 550.16(C) (3), 551.56(F), 552.57(F) Electrical, Tables 311.60(C)(77) through 31 l.60(C) (80), Annex B, Table B.2(5) Definition, 311 .2 Fixed indusu·ial process heaters in, 425- V Lum inaires in, 410.lO(C) Wiring in, 300.21, 300.22, 725.135(B), Table 72.5.154, 760.3(B) , 760.53(B) (1), 760.135(B), 770.26, 770.113(B), Table 770.154(a), 800.113(B), Tables 800.154 (a) through (c), Fig. B.3 Dumbwaiters, see Elevators, drnnbwaiters, escalators, moving walks, p latform lifts, and stairnray chairlifts Dust-ignitionproof, 500.7( B), 502.15, 506.S(A) Definition, Art. 100 Dusts, combustible, see also Hazardous (classified) locations Definition, Art. 100 Dusttight, 500.7(C), 500.8(C) (6), 506.8(D) Definition, Art. l 00 Duty, types, see also Motors, Continuotts duty Definitions, Art 100

Intermittent duty, 430.22(£), 430.33 Short-time duty, 430.22(E), 430.24(4) Ex. 1, 430.33 Varying duty, 430.22(E), 430.24 Ex. No. 1, 430.33 Duty cycle, welding, 630.31, Table 630.3l (A) Dwellings, see also Appliances; Boxes; Grounding, and similar general categories Arc-fault circuit-interrupter protection, 210. 12 (A), 210.12(D) Branch-circuit voltages, 210.6(A) Communications circuits, 800.11 3(G), 800.l 13(K), 800.l 13(L) Definitions, Art 100 Energy storage systems, 706.20(B) Farm, services, 220.102(A), 220. 103 Feeder load, calculations for, 220.14(J), 220. 16(A), 220.82 through 220.85, Annex D Fire alarm circuits, powerlimi ted, 760.135(G) Ground-fault circuit interrupter protection, 210.8(A) Lighting ouclets required , 2 10. 70(A) Luminaires, 410.135, 410. 140(B); see also Luminaires Optical fiber cables and raceways, installation, 770.l 13(G) Panel boards as senkes, 408.36 Ex.3 Receptacles Circuits, 210.11 Outlets, 210.S(A), 210.52 Tamper-resistant, 406.12 Remote-control, signaling, and power-limited circuit cables, installation, 725.13.5 (G), 725. 135(L), 725. 135(M) -E-

Eccentric knockouts, see Knockouts Effective ground-fault current path Definition, Art. 100 Elbows, metal, protection from corrosion, 300.6 Electrical datum plane, 555.3 Definition, Art. 100 Electrical ducts, see Ducts

NATIONAL ELECTRICAL CODE

2020 Edition

INDEX

Electr ical life support equipmen t, 517.45( B) Definition, 517.2 Electrically operated pool covers, S£e Covers Electrical metallic tubing (Type EMT), Art. 358 Bends, 358.24, 358.26, Chap. 9, Table 2 Connectors and couplings, 358.42 Construction specifications, 358-lll Definition, 358.2 Dimensions, Chap. 9, Table 4 Expansion fittings, 300.7( B) IN Grounding, 358.60 Installation, 3.58-11 Listing, 358.6 Marking, 358.120 Maximum number of conductors and fixture wires in , Tables C.l and C.l A Number of conducwrs, 358.22, Chap. 9 , Table 1 Reaming and threading, 358.28 Securing and supporting, 314.23(E), 358.30 Size, 358.20 Splices and taps, 358.56 Uses not permitted, 358.12 Uses permitted, 3.58.10 Electrical noise, 647.3. See also Sensitive electronic equipment Grounding, 250.146(D) Receptacles, 406.3(D) Electrical nonmetallic tubing (Type ENT), Art. 362 Bends, 362.24, 362.26, Chap. 9, Table 2 Bushings, 362.46 Construction specifications, 362-III Definition, 362.2 Dimensions, Chap. 9, Table 4 Grounding, 362.60 l nstallation, 362-11 J oints, 362.48 Listing, 362.6 Marking, 362.120 Maximum number of conductors and fixture wires in, Tables C.2 and C.2A Number of conducwrs, 362.22, Chap. 9, Table 1 Securing and supporting, 362.30 Size, 362.20

2020 Edition

Splices and taps, 362.56 Temperature limitations, 362.10(9) Through metal framing members, 300.4(B) Trimming, 362.28 Uses not permitted, 362.12 Uses permitted, 362.10 Electrical resistance trace heating " 60079-30-1 "' 505.8(1)' 506.80) Definition, Art. 100 Electric-discharge lighting, Art. 410 Connection of Iuminaires, 410.24, 410.62(C) Definition, Art. 100 Emergency systems, 700.15(C) Hazardous (classified) Class I locations, 501.130(B) (6) Lamp auxiliary equipment, 410.104 Marking, 410.146 1000 volts or less, 410- XJ I Over 1000 volts, 410-XIII Signs and outline lighting, Art. 600 Electric h eating equipment, fixed , S£e Fixed e lectric heating equipment for pipelines and vessels; Fixed electric spaceheating equipment; Fixed outdoor electric deicing and snowmelting equipmem Electric power production and distribution network Definition, Art. 100 Electric power production sources, see Generators; Imerconnected electric power production sources; Solar photovoltaic systems; ·wind electric systems Electric signs, see Signs, elect.-ic Electric supply stations Definition, 691.2 Large-scale solar photovoltaic systems, Art. 691 Electric vehicle power export equipment (EVPE), 625.48, 625.60 Definition, 625.2 Electric vehicle p ower transfer system, Art. 625 Cords and cables, Table 400.4, 625.17 Definitions, 625.2 Disconnecting means, 625.43

NATIONAL ELECTRICAL CODE

Equipment construction, 625-11 Installation, 625-lll Interactive system, 625.48 Listed, 625.5 Location, 625.50 Personnel protection system, 625.22, 625.54, 625.60(D) Definition, 625.2 Primary source, loss o( 625.46 Rating, 625.42 Venti lation, 625.52 Voltages, 625.4 Wireless power transfer equipment, 625- IV Electric vehicles Definition, Art. 100 Electric vehicle supply equipment Definition, 625.2 Equipment connection, 625.44, 625.52( B)(4) Fastened in p lace, 625. 17(C) (2), 625.44(B) Definition, 625.2 Fixed in place, 625.44(C) Definition, 625.2 Interactive systems, 625 .48 Interconnecting cabling systems, 625.l 7( D) Location, 625 ..50 Overcurrem protection, 625 .41 Portable equipmem, 625. I 7(C)(l) Definition, 625.2 Electric welders, see Welders, electric Electrified truck p arking space equipmen t, Art. 626 Definitions, 626.2 General requirements, 626.4 Supply equipment, 626-III Transport refrigerated unit, 626-IV Wiring systems, 626-1I Definition, 626.2 Electrode industrial p rocess heating equipment, see Fixed resistance and elecu·ode industrial process heating equipment Electrodes, grounding, 250.64(F); see also Grounding electrode conductors Aluminum, 250.52( B) (2) Common, 250.58 Concrete-encased, 250.50 Ex., 250.52(A) (3), 250.66(B), 250.68(A) Ex. I, 250. 70 Definition, Art. 100

Fuel cell systems, 692.47 Gas piping as, 250.52(B) (1) Intrinsically safe apparatus, 504.50 (C) Metal frame of building as, 250.30(A) (8), 250.52(A) (2), 250.68(C) Metal water piping system, 2.50.30(A) (4), 250.30(A) (8), 250.52(A)( l ), 2.50.68(C) Separately derived systems, 250.30(A) ( 4), 250.30(B) (2), 250.30(C) System installation, 250.53 Wind electric systems, 694.40(B) Electrolytes, 480.9 Definition, 480.2 Flow battery energy systems, 706-V Electrolytic cells, Art. 668 Auxiliary nonelectric connections, 668.31 Cell line conductors, 668.12 Cell line working zone, 668.10 Definition, 668.2 Cranes and hoists, 668.32 DC cell line process power supply, 668.11 Definitions, 668.2 Disconnecting means, 668.13 Enclosures, 668.40 Fixed electrical equipment, 668.30 Grounding, 668.15 Portable electrical equipment, 668.20, 668.21, 668.30 Shw1ting means, 668.14 Electronically actuated fuse, 240.67(B), 240.l Ol (A), Table 450.3(A) Note 4 Definition, Art. 100 Electronically protected motors, 430.7(A)( l 6), 430.32(A) (2), 430.32(B)

(2) Definition, 430.2 Electr onic computer/ data processing equipmen t, see Information technology equipment Electronic lighting control switches, 404.22 Electronic p ower converters, 690.4(F), 690.8(A)(2), 690.9(A), 690.53 Definition, 690.2 Electroplating systems, Art. 669

70-861

NATIONAL E LECTRICAL CODE

Branch-circuit conductors, 669.5 Disconnecting means, 669.8 Overcurrem protection, 669.9 Warning signs, 669.7 Wiring methods, 669.6 Electrostatic equipment, spraying and detearing p aint, 516.6( E), 516.10 Elevators, dumbwaiters, escalators, moving walks, platfor m lifts, and stairway chairlifts, Art. 620 Cables Flexible, Table 400.4, 400.10(A)(4), 620.21 Traveling, 620.ll(B), 620.12(A), 620-V Clearances, working, 620.5 Conductors, 620- 11 through 620-IV Definitions, 620.2 Disconnecting means and control, 620- VI , 620.91 (C) Emergency and standby power systems, 620- X Essential electrical systems, 517.33(G), 517.43(F) Grounding, 250.112(E), 250.JJ6, 250.136, 620- lX Live parts, 620.4 Machine room, 620-Vlll Overcurrent protection, 620-Vll Voltage limitations, 620.3 Wiring, 620-lll Working clearances, 620.5 Emergency systems, Art. 700; .see also Exits, emergency lighting for; Legally required standby systems; Optional standby systems Capacity and rating, 700.4 Circuits for lighting and power, 700-IV, 700- V Circuit wiring, 70()-lf Connections at services, 230.82 Control, 700-V Definitions, 700.2 Elevators, dumbwaiters, escalators, etc., 620-X Grounding, 700.7( B) Overcurrent protection, 700.lO(B), IN Fig. 700. lO(B) (a), IN Fig. 700.lO(B) (b), 700-VI Service disconnecting means, 230.72(B) Services, 230.2(A)

70-862

Signals, 700.6 Signs, 700.7 Sources of power, 700.3( F), 700-111 Tests and maintenance, 700.3 Transfer equipment, 700.5 Unit equipment, 700.12( 1) Wiring, 700.10, IN Fig. 700. lO(B) (a), I N Fig. 700. lO( B) (b) . Enamel, coating of General equipment, indoor use only, 300.6(A) (1) Metal boxes, 314.40(A) Removing for grounding connections, 250.96(A) Rigid metal conduit, 344. JO(A) (3) Encapsulation " m", 505.8(G) , 506.8(E) Definition, Art. IOO Enclosed Definition, Art. 100 Enclosu res, see alrn H azardous (classified) locations Arcing parts, 110.18, 515.7( B), 516.7( B) Bonding, 250.96, 250.146 Busways, 368.237 Cabinets and cutout boxes, 312.7 through 312.9, 312.ll( D) Circuits in, number of; 90.8( B) Cranes, hoists, resistors, 610.3( B) Definition, Art. 100 Electrolytic cells, 668.40 Elevators, dumbwaite rs, escalators, etc., 620.4, 620-Vlll Entrances, 110.33(A) Exits, 300.25 Fire a larm circuits and conductors, 760.48, 760.49(A), 760.53(A)(l), 760.130(B)(l), 760.133, 760.136, 760.139 Grounding, 250.64(D), 250.64(E), 250-lV Handhole enclosures, 314.29, 314.30, 314-1\1 Definition, Art. 100 High-intensity discharge lamp auxiliary equipment, 410.104(A) Indoor use, for, Table 110.28 Induction and dielectric heating, 66.5 .20 Industrial control panels, 409.100

Installations over 1000 vo lts, 110.31 Intrinsically safe systems, 504.lO(C), 504.30(A) (2), .504.50(A) Low-voltage suspended ceiling power distribution systems, 393.40(B) Membrane Definition, Art. 100 Spray application operations in, 516--1\1 Mod ular data centers, 646.7(C), 646.9 Neon transformer, as pull boxes, 600.5( D) (2) Outdoor use, for, Table 110.28 Overcurrent protection, 230.208(B), 240-111, 312.8 Panelboards, 408.38 Portable stage equipment, 520.62(A) Pressurized enclosure "p", 505.8( B), 506.8(H) Definition, Art. 100 Protection by enclosure "t", 506.8(G) Definition, Art. 100 Rad io equipment, 810.7l(A) Resistors and reactors over 1000 volts, 470.18( B) Signs, 600.8, 600.42( H) Switches, 312.8, 404.3, 404.12, 404.28, 450.8(C) Types, 110.28 Unde rground, 110.59; see also Manholes; Vaults Energized Definition, Art. 100 Energized parts, see also Live pa rt~ Fire pumps, 695.12(D) Motors, motor circuits, and controllers, 430-Xll Ener gy management systems, Art. 750 Alternate power sources, 750.20 Definitions, 750.2 Field markings, 750.50 Load management, 750.30 Energy storage systems, Art. 706 Charge conu·ol, 706.33 Circuit requirement.~, 706--1\1 Connection to other energy sources, 706.16 Definitions, 706.2 Directory, 706.21 Disconnecting means, 706- 11 Flow banery systems, 706- V Installation requirement~, 706- lll

Multiple systems in single building, 706.6 Nameplates, 706.30(A) ( 1) Other systems, 706--\11 Overcurrent protection, 706.31 Enforcement of, 90.4, .510.2, Annex H Engineering super vision, 310.14(B), 645.25 Entertainment d evices Definition, 522.2 Equipment, see also specific types of equipment Approval, see Approval, approved Cooling of, l I0.13(B) Definition, Art. 100 Examination of; 90.7, 110.3 Grounding, 250-\11 Installation, general provisions, Art. 1 10 Less than 50 volts, Art. 720 More than l 000 volts, Art. 490 Mounting, see Mounting of equipment Sealable Definition, Art. 100 Service, see Service equipment Signal, see also Audio signal processing, amplification, and reproduction equipment; Signaling circuits Definition , 620.2 Equipment b onding jumpers, see J umpers, bonding Equipment branch, 517.25, 5 17.29 IN, 517.31 (A), 517.40 IN No. 2, 517.42(A), 517.43, 517.44 Definition, 517.2 Equipment grounding conductor fill and boxes, 314. 16(B) (5) Equipment grounding conductors Agricultural buildings, 547.5(F) Armored cable (Type AC) as, 320.108 Cable trays as, 392 .10 (B) ( l) , 392.60 Capacitor cases connected to, 460.10, 460.27 Carnivals, circuses, fairs, equipmem at, 525.30, 525.31, 525.32 Community antenna television and radio disu-ibution systems, 820.100 Ex. Connections at outlets, 250. 146, 250. 148, 400.33

NATIONAL ELECTRICAL CODE

2020 Edition

INDEX

Definition, An. 100 Fire alarm systems, 760.3(0) Fire resistive cab le systems, 728.60 FLxed outdoor electric deicing and snow-melting equipment, 426.44 Fuel cell systems, 692.44, 692 .45 Hazardous (classified) locations, 501.30(8 ), 502.30(8 ), 503.30(8), 506.2.5(8 ) Health care facilities, 517.13, 517.19(E), 517.l 9(G) Identification, 2 L0.5( 8 ), 250.119, 311.14, 400.23, 520.44(C) (3) Information technology equipment, 645 .5(E) (2), 645.15 Installation, 215.6, 250.120, 2.50.130 Intrinsically safe apparatus connected to, 504.50(A) Luminaires, 410.42, 410.44, 410.46 Marinas, boatyards, floating buildings, and docking facilities, 555.37, 555.56(8 ) Messenger-supported wiring, 396.30(C) Metal-clad cable (Type MC) as, 330.108 Mineral-insulated metalsheathed cable (Type Ml ) as, 332.108 Mobile homes, 550.16(B) Motion picmre and televL~ion studios, 530.11, 530.20, 530.22 (A) , 530.64( 8 ) Motor control centers, 430.96 Motor terminal housings, 430.12(E) Nonmetallic sheathed (Type NMS) cable as, 334.108 Panelboards, 408.40 Parallel, 310.10(G)(5) Park trailers, interior equipment, 552.56(8 ) Portable cables over 600 volts, 400.31 (B), 400.32, 400.33 Receptacles and cord connectors, 406.3( D) (I), 406.4, 406.10 Recreational vehicles, 551.54, 5.51.55 Resistor and reactor cases/ enclosures connected to, 470.19 Restricted use, 250.121

2020 Edition

Sensitive electronic equipment, 647.6( 8 ) Signs and outl ine lighting, 600.7(A) Sizing, 250.122, 250.190(C)(3) Snap switches, generaluse, 404.9(8 ) Solar photovoltaic systems, 690.43 through 690.47 Spas and tubs, 680.8(B) Swimming pools, 680.8(8), 680.23(B) (3), 680.23( 8 )(4), 680.23(1') (2) , 680.23(F)(3) Switchboard, stage, 520.51 Switch enclosures connected to, 404.12 Switchgear and control assemblies frames connected to, 490.36, 490.37 Systems and circuits over I kV, 250.190(C) Temporary installarions, .590.4(D ), 590.4( 1'), 590.4(G) Ex. No. 1, 590.6(A) Lx., 590.6(8 ) (2) Tunnels, 110.54(8) Type P cable as, 337.108 Types recognized, 250.118, 250.120, 250.134 Underground feeder and branch-circuit cable, 340.108 Wind electric systems, 694.40 Equipment racks, 640.21 (E), 640.22, 640.42, 640.43 Definition, 640.2 Equipotential plane, 547.10, 680.26, 682.33 Definition, Art. 100, 547.2 Escalators, see Elevators, dumbwaiters, escalators, moving walks, p latform lifts, and stairway chairlifts Essential electrical systems, health care facilities, see Health care facilities Examples (calculations), Annex D Exciters Leads in enclosure with other conductors, 300.3(C) (2) (b)

Overcurrent protection for, 445.12(A) Exhaust ducts, see D uccs Exit enclosures Stair towers, 300.25 Exits, emergen cy lighting for , 517.33(A),

NATIONAL ELECTRICAL CODE

517.33(8), 517.43(A), 517.43( 8 ), 646.16, 646.17, 700.12( 1) (2), 700.16 Exit signs Health care facilities, 517.33( 8 ), 517.43(8) Expansion joints (fittings), 250.98, 300.7(B), 352.44, 355.44, 366.44, 368.244, 424.98(8), 424.99(8) (1 ), 426.20(E), 426.21 (C), 426.22(D), 427. 16 Explanatory material, IN, 90.5(C) Explosionproof equipmen t, 500.7(A), 501.10( 8 ) (4), 502.5, 505.16( 8 )(2) Definition, ArL 100 Explosive atmospheres, gases , liquids, dusts, ignitible fibers/flyings, and lint, see Hazardous (classified) locations Exposed, see alrn Enclosures Cable trays, 392.18( E) Conductive surfaces, 517.1 1 Definition, 517 .2 Definition, 770.2, 800.2 Deicing and snow-melting equipment, 426.21 Electrical metallic tubing, 358.lO(A) Hazardous (classified) locations, 501.25, 502.25, 503.25, 505.19 Live parts, l L0.26 Definition, ArL 100 Luminaire parts, 410.5, 410.42, 410.46 Metal wireways, 376.10( 1) Nonmetallic extensions, 382 .10 (8 ) Receptacle terminals, 406.5(1) Recreational vehicle site supply equipment, 551.76( 8 ) Strucmral metal, grounding, 250.52(A) (2) Transformers, 450.8(C) Wiring methods Definition, Art. JOO Open wiring on insulators, 398.15 Extension cord sets On construction sites, 590.6(A), 590.6( 8 ) (2) Overcurrent protection, 240.5 Temporary installations, 590.4(J) , .590.6(A), 590.6(B) (2) Extensions Auxiliary gutters, 366.12

Cellular metal floor raceways, 374.18(A) Flat cable assemblies, 322.40( D) Lighting systems operating at 30 voles or less, conductors for, 411.5 (A) Nonmetall ic, see Nonmetallic extensions Surface, boxes and fittings, 314.22 Surface raceways, 386.10(4), 388.10(2) Wireways, 376.70, 378.10(4), 378.70 E xternally operable Definition, Art. 100 -F-

Faceplates Grounding, 404.9(8 ), 406.6( 8 ), 550.15(D) Material, 404.9(C), 406.6 Minimum thicknesses for, 404.9(C), 406.6(A) Mobile homes, 5.50.l.5(D) Mounting surfaces, against, 404.9(A), 406.5, 406.9(E) Fairs, see Carnivals, circuses, fairs, and similar events Fans, ceiling, see Ceiling fans Farm buildings, feeder calculations, 220.102. See also Agricultural buildings Fasten ed in place, 625.l 7(C) (2), 625.44( 8 ) Definition, 625.2 Fault curren t, l 10.24(A) Available, Fig. 100.1, 110.24 Definition, Art. 100 Definition, Art. 100 Fault protection d evice, 830.44( F) (3) Ex., 830.47(C) Ex. Definition, 830.2 Fault-tolerant exter nal control circuits, 695. l 4(A) Definition, 695.2 Feed er a ssembly, mobile homes, 550.lO(A) Definitions, 550.2 Feed ers, Art. 2 15, Art. 220 Ampacities, 310. 12(C) 8 usways, 368. 17 Calculation of loads, see Loads Critical operations power systems, 708-11, 708.52( 8 ) Definition, Art. 100

70-863

NATIONAL E LECTRICAL CODE

EleClric vehicle supply equipment, 625.41, 625.47 Elevators, dumbwaiters, escalators, etc., 620.1 3, 620.37(C) Emergency systems, 700.10(8), IN Fig. 700.10(8 )(a), IN Fig. 700.l0(8)(b), 700.lO(D) Energy management systems, 750.30(C) Equipment grounding conductors, 250.122(G) Farm buildings, for, 220.102 foe pumps, 695.3, 695.4(8)(1), 695.5(C), 695.6(A)(2) Ground-fault circuit interrupters, with, 215.9 Grounding means, 215.6 Identification, 225.37, 225.52(F), 230.2(E) Interconnected electric power production sources, 705.12( 8 ) (l ) Kitchen equipment, commercial, 220.56 Loads, see Loads, feeders Marinas, boatyards, floating buildings, and docking facilities, 555.6, 555.34(8 ) (2), 555.3.5(A)(3), 555.37( E), 555.51, 555.53 Mobile homes and parks, 550.lO(A), 550-111 Modular data centers, 646.6(8 ) (2), 646.7(B), 646.8 Motion picture snidios, 530.18( 8 ) Motors, 430-11 Outside, see Outside branch circuits and feeders Overcurrent protection, 215.3 Accessibility, 240.24(A) Motor, 430-V Park trailers, 552 .43 (A) Piers, 682.15( 8 ) Pools, permanently installed, 680.25 Recreational vehicle sites, 551. 73, 551.80 Relocatable structures, 545.22 (A) Restaurants, 220.88 Services, 220-111 Stage switchboard, 520.27 Taps, 240.21( 8 ) , 240.92(8 ), 430.28, 646.6(8) (2)' 725.45(8) Television studio sets, 530.19

70-864

X-ray equipment, 660.6(8 ) Feed-through conductors, 312.ll( D) Fences, grounding and bonding of, 250.194, 691.11 Ferrous metals, see also Rigid metal conduit (Type RMC) Induced currents in enclosures or raceways, 300.20 Protection from corrosion, 300.6(A) Festoon cable, 610.l3(C) Definition, 610.2 Festoon Lighting Conductor size, 225.6(8 ) Definition, Art. 100 Insulation, 225.4 Portable stage eq uipmenL, 520.65 Festoon wiring, por table stage equipment, 520.65 Fiber bushings, AC cable ends, 320.40 Fibers/ flyings, lint, ignitible, ArL 503, ArL 506; see also HazardotL~ (classified) locations Field evaluation body (FEB) Definition, ArL 100 Field labeled Definition, ArL 100 Interactive inverters, 705.6 Photovoltaic equipmenL, 690.4(B), 690.12( 8 ) (2), 691.5(2) Service eq uipmenL, 230.66 Stand alone systems, 710.6 Wind electric systems, 694.7(8 ), 694.7( F) Figures, see Diagrams Films, motion picture, see also Prqjection rooms, motion picture Storage vaults, 530-V Viewing, cutting, patching tables, 530-IV Finish rating, 334.10(3), 362.10, 518.4(C) Definition, 362.10(2) IN Fire alarms, 230.82(5), 230.94 Ex. 4; see also Fire alarm systems Fire alarm systems, ArL 760 Abandoned cables, 760.25 Definition, 760.2 Access to e lectrical equipmem, 760.21 Cables, 760.3, 760.48, 760.176, 760.179, 840.47(A)(l)

Circuits extending beyond one building, 760.32 Connections at services, 230.82 (5), 230.94 Ex. 4 Critical operations power systems, Art. 708 Definitions, 760.2 Grounding, 250.112(1) Health care facilities, 517.33(C), 517.43(C), 517- Vl Identification, 760.30 Installation, 760.32 Location, 760.3 Mechanical execution of work, 760.24 Non power-limited circuits, 760-11 Cable marking, 760.176 Conductors, 760.49(8) Different circuits in same raceway, etc., 760.48, 80.5.47(A) Number of conductors in raceway, etc., and derating, 760..51 Definition, 760.2 Listing, 760.176 Marking, 760.176 Multiconductor cable, 760.53 Optical fiber cables, 760.3(F), 840.47(A) (1) Overcurrent protection, 760.43, 760.45 Power source requirements, 760.41 Requirements, 760.35(A) Wiring method, 760.46, 760.53(A) Power-l imited circuit~, 760-lll Cable markings, 760.179 Circuit markings, 760.124 Conductors Separation, 760.136 Size, 760. 142 Support, 760.143 Definition, 760.2 Installation, 760.133, 760.139 Line-type fire d etectors, 760.145, 760.l 79(J) Listing, 760.179 Marking, 760.179 Overcurrent protection, Chap. 9, Tables 12(A) and 12(8 ) Power sources, 760.121 Requi rements, 760.35(8) Wiring methods and materials Load side, 760.130

Supply side, 760. 127 Fire d etectors, linetype, 760.179 (I) Fire pumps, ArL 695 Connection at services, 230.72(A) Ex., 230.72(B), 230.82(5), 230.94 Ex. 4 Continuity of power, 695.4 Control wiring, 695.14 Defi nitions, 695.2 Emergency power supply, Art. 700 Equipment location, 695.12 Grounding, 250.l 12(L ), 250. l 12(M) Listing, 69.5.6(H), 695.10 Motor, overcurrent protection, 430.31 On-site standby generator, 695.3 (B) (2), 695.3(D), 69.5.4(8), 695.6(C) Ex. 2 Definition, 695.2 Overcurrent protection, service equipment, 230.90(A) Ex.4 Power sources to electric motordriven, 695.3 Power wiring, 69.5.6 Remote-control circuits, 430.72(8) Ex. l Services, 230.2 (A) (1), 230.90(A) Ex.4 Supervised connection, 695.4 Transformers, 69.5.5 Volcage drop, 695.7 Fire-resistive cable systems, Art. 728 Definition, 728.2 Equipment grounding conductors, 728.60 Installation, 728.5 Marking, 728. 120 Fire spread Prevention of, wiring me!.110ds, 300.21, 760.3(A), 770.26, 800.26, 840.26 Fire-stopped partitions, 300.2 1; see also Firewalls Firewalls, wiring through, 300.21 Fittings, Art. 314; see also Chap. 3, Wiring Methods and Materials Conduit bodies, 314.16 Cords, flexible, 400.35 Definition,Art.100 Expansion, see Expansion joints (fittings)

NATIONAL ELECTRICAL CODE

2020 Edition

INDEX

Flat cable assemblies, installed with, 322.40(C) Insulation, 300.4 (G) Integrated gas spacer cable, 326.40 Fixed electric heating equipment for pipelines and vessels, Art. 427 Continuous load, 427.4 Control and protection, 427- Vll Controls, 427.56 Disconnecting means, 427.55 Overcurrent protection, 427.57 Definitions, 427.2 Impedance heating, 427- IV De fi nition, 427.2 Grounding, 427.29 Induced currents, 427.28 Iso lation transformer, 427.26 Pe rsonnel protection, 427.25 Secondary conductor sizing, 427.30 Voltage limitations, 427.27 Induction heating, 427- V Definition, 427.2 Induced current, 427.37 Personnel protection, 427.36 Scope, 427.35 Jnstallation, 427-ll General, 427.10 Identification, 427.13 Thermal protection, 427.12 Use, 427.11 Resistance heating elements, 427- III Definition, 427.2 Electrical connections, 427.19 Eq uipment p rotection, 427.22 Expansion and contraction, 427. 16 Flexural capability, 427 .17 Grounded conductive covering, 427.23 Marking, 427.20 Not in direct contact, 427.15 Power supply leads, 427.18 Secured , 427.14 Skin effect h eating, 427-VI Conductor ampacity, 427.45 Definition, 427.2 Grounding, 427.48 P ull boxes, 427.46 Single conductor in enclosure, 427.47 Fixed electric space-heating equipment, Art. 424 Branch circuits for, 424.4 Boilers, 424.82

2020 Edition

Low-voltage equipment, 424.104 Radiant heating panels, 424.95, 424.96 Cables, 424- V Area restrictions, 424.38 Ceilings Clearances, 424.36 Finished, 424.42 Clearances, wiring Ceilings, 424.36 Other oqjec L~, openings, 424.39 Construction, 424.34 Installation In concrete or poured masonry floors, 424.44 Nonheating leads, 424.43 Marking, 424.35 Splices, 424.40, 424.41 (D) Tests and inspections, 424.46 Control and protection, 424- IIJ Controllers, 424.20(A) Disconnecting means, 424.19 th roug h 424.21, 424.65 Indicating, 424.21 Overcurren t protection, 424.22, 424.72, 424.82 Definitions, 424.2 Duct heaters, 424- VI Airflow, 424.59 Condensation, 424.62 Disconnecting means, location, 424.65 Elevated inlet temperature, 424.60 Fan circuit interlock, 424.63 Identification, 424.58 Installation, 424.61, 424.66 Limit controls, 424.64 Electrode-type boilers, 424-VIII Installation, 424-11 Location Damp or wet locations, 424. 12( B) Exposed to physical damage, 424.12(A) Low-vo ltage equipment, 424.103 Spacing, combustible materials, 424.13 Special permission, 424.10 Supply conductors, 424.11 Listed , 424.6 Load, 220.51, 220.82(C), 220.83 Low-vo ltage, 424-X Marking, 424-rv Boile rs, 424.86

NATIONAL ELECTRICAL CODE

Cables, 424.35, 424.47 Heating elements, 424.29 Nameplates, 220.82(C), 424.28 Radiant heating panels and heating panel sets, 424. 92 Overcurrent protection for, 424.22, 424.72, 424.82 Radiant heating panels and heating panel sets, 424-I X, 427.23( B) Clearances, wiring Ceilings, 424.94 Walls, 424.95 Connection, 424.96 Installation, 424.93, 424.98, 424.99 Markings, 424.92 Nonheating leads, 424.97 Resistance-type boilers, 424-VI I Fixed equipment, ground ing, 250. 110, 250. l 12, 250.116, 250.134, 250.136, 250.190 Electric space-heating equipment, 424.45( F), 424.99(B) (6) Patient care areas, 51 7.13 Fixed in place, 625.44(C) Definition, 625 .2 Fixed outdoor electric d eicing and snow-melting equipment, Art. 426 Branch circuits for, 210. 19(A)(4) Ex. l (5) Connections, 426.24 Continuous load, 426.4 Control and protection, 426--VI Cord-and -plugcon nected, 426.50(B), 426.54 Definitions, 426.2 Disconnecting means, 426.50 Ground-fault circuit interrupters, 210.8(A) (3) Ex. Grounding, 426.22(A), 426.27, 426.44 Identification of; 426. 13 Impedance heating, 426-IV Definition, 426.2 Induced currents, 426.33 Isolation transformer, 426.31 Personnel protection, 426.30 Voltage limitations, 426.32 Installation, 426--11 Marking, 426.25 Nonheating leads, instal lation of, 426.22, 426.23

Protection Corrosion, 426.26, 426.43 Exposed equipment, nonheating leads for, 426.23(B) Ground faul t, 210.8(A) (3) Ex., 426.28 Thermal, 426. 12 Resistance heating e lemen ts, 426- III De fi nition, 426.2 Embedded, 426.20 Exposed, 426.21 Skin effect heating, 426--V Conductor a mpacity, 426.40 Definition, 426.2 Pull boxes, 426.41 Single conductor in enclosure, 426.42 Special permission, 426. 14 Thermostats fo r, 426.51 Use of, 426.11 Fixed resistance and electrod e industrial process heating equipment, Art. 425 Boilers E lectrode-type, 425- Vll Resistance-type, 425- Vl Contro l and protection, 425-III , 425.65 Duct h eaters, 425- V Installation, 425-11 Marking, 425-IV Conductors, overcurrent protective devices, 425.72( E), 425.72(F) Duct heaters, 425.58 Electrode-type boilers, 425.81, 425.86 Resistance-type boilers, 425. 71 Fixtures, see Lum inaires Fixture wires, Art. 402 Ampacities, 402.5 Grounded co nductors, identification, 402.8 Marking, 402.9 Minimum size, 402.6 Number in conduits or tubing, 402.7 Overcurrent protection, 240.5, 402. 12 Types, 402.3 Uses not perm itted, 402.11 Uses permitted, 402. 10 Flameproof " d ", 505.8(A) Definition, Art. 100 Flame spread, see Fire spread

70-865

NATIONAL E LECTRICAL CODE

Flammable anesthetics, see also Anesthetizing locations Definition, 517.2 Flammable gases, see Hazardous (classified) locations Flammable-liquid p roduced vapors, see Hazardous (classified) locations Flammable liquids, see Hazardous (classified) locations Flashers, time switches, etc., 404.5, 600.6(B) Flat cable assemblies (Type FC), Art. 322 Boxes and fittings, 322.40 Branch·drcuit rating, 322.10(1) Conductor insulations for, 322.112 Conductor size, 322.104 Construction, 322-lll Dead ends, 322.40(A) Definition, 322.2 Extensions from, 322.40(D) Fittings for, 322.40(C) Identification of grounded conductor, 322.120(B) Installation, 322-11 Luminaire hangers, 322.40(B) Marking, 322.120 Number of conductors in, 322.100 Size of conductors in, 322.104 Splices, 322.56 Support, 322.30 Terminal b lock identification, 322.120(C) Uses not permitted, 322.12 Uses permitted, 322.10 Flat conductor cable (Type FCC), Art. 324 Branch-circuit rating, 324.IO(B) Cable connections and ends, 324.40(A) Construction, 324-111 Conductor identification, 324.120(B) Insulation, 324.112 Markings, 324. 120(A) Receptacles and housings, 324.42 Shields, 324.lOO( B) Definitions, 324.2 Transition assemblies, 324.56 ( B) Definition, 324.2 Definitions, 324.2 Grounding, 324.60 Installation, 324-11 Alterations, 324.56(A) Boxes and fittings, 324.40

70-866

Cable connections and insulating end s, 324.40(A) Connections to other systems, 324.40( D) Crossings, 324.18 Floor coverings, 324.41 Heated floors, 324.lO(F) Metal shield connectors, 324.40( E) Receptacles and housings, 324.42 Shields, 324.40(C), 324.40(E) Definition, 324.2 Support, 324.30 System height, 324.lO(G) Insulating ends, 324.40(A) Definition, 324.2 Listing requiremenL~, 324.6 Po larization, 324.40( B) Splices and taps, 324.56 Systems alterations, 324.56(A) Uses not permitted, 324.12 Uses permitted, 324.10 Flatirons Cords, 422.43(A) Signals, 422.42 Stand s for, 422 .45 Temperature-l imiting means, 422.42, 422.46 Flexible cords, see Cords, flexible Flexible metal conduit (Type FMC) , Art. 348 Bends, 348.24, 348.26, Chap. 9, Table 2 Couplings and connectors, 348.42 Definition, 348.2 Dimensions, Chap. 9, Table 4 Grounding and bonding, 348.60 Installation, 348-11 Liquidtight, see Liquidtight flexible metal conduit Listing, 348.6 Maximum number of conductors and fixmre wires in, Tables C.3 and C.3A Number of conductors, Chap. 9, Table I Number of conductors in, 348.22 Securing and supporting, 348.30 Size, 348.20 Splices and taps, 348.56 Trimming, 348.28 Uses not permitted, 348.12 Uses permitted, 348.10 Flexible metallic tubing Bends, Ornp. 9, Table 2

Number of conductors, Chap. 9, Table I Flexible metallic tubing (Type FMT), ArL 360 Bends, 360.24 Construction specifications, 360--Ill Definition, 360.2 Grounding, 360.60 Installation, 360--11 Listing, 360.6 Marking, 360.120 Number of conductors, 360.22 Sizes, 360.20 Splices and taps, 360..56 Uses not permitted, 360.12 Uses permitted, 360.10 Floating buildings, see Marinas, boatyards, floating buildings, and docking facilities Floor pockets, 520.46 Floors, see also Underfloor raceways Busways through, 368.lO(C) (2) Cablebus support and extension through, 370.18 Flat conductor cable (Type FCC) in/ on, 324. IO(C) Floor coverings, 324.41 Heated floors, 324.lO(F) Insulating ends, 324.41 Masonry or concrete floors, installation of heating cables in, 424.44 Radiant heating panels, installation of, 424-IX Receptacles, 210.52(A) (3), 250.146(C), 314.27( B), 406.9(0 ) Surface metal raceways Extension through floors, 386.10(4) Under raised floors, 386.10(3) Surface nonmetallic raceways, 388.10(2) Flue damper control, see Dampers (flue), control Fluorescent luminaires, 410- XI I, 410--Xlll Autotransformers in ballasts, 220.18(B), 410.138 Auxiliary equipment, 410.104, 410.137 Ba llast protection required, 410. L30(E) Circuit breakers used to switch, 240.83(0 ) Connection of, 410.24, 410.62(C)

Disconnecting means, 410.130(G) Load calculations, branch circuits, 210.23 Raceways, 410.64 Snap switches for, 404.14(A) (5), 404. 14(B)(4) Surface-mounted or recessed, 410. 16(A), 410. 16(C) Thermal protection, 410.130(E) Fluoroscopic equipment, see X-ray equipment Flyings, ignitible, Art. 503, An. 506; see also Hazardous (classified) locations Fo otligh ts, theaters, 520.43 Definition, 520.2 Disappearing, 520.43(C) Formal interpretations, 90.6 Forming shells, underwater pool luminaires, 680.23( B), 680.24, 680.26(B)(4), 680.27(A) (3) Definition, 680.2 Fountains, see Swimming pools, fountains, and similar installations Foyers, receptacles in, 210.52(1) Frame, recreational vehicle Definition, 55 1.2 Free air, 310.21 Ampacities of conductors in, 310.J 7, Table 310.17, 310.19, Table 310.19, Table 310.21 Definition, Art. 100 Fuel cell systems, Art. 692 Circuit requirements, 692-11 Connection at services, 230.82(6) Connection to ot11er circuits, 692- Vll Identified interactive equipment, 692.60 Loss of interactive system power, 692.62 Output characteristics, 692.61 Point of connection, 692.65 Transfer switch, 692.59 Unbalanced interconnection, 692.64 Critical operations power systems, 708.20(H) Definitions, Art. 100, 692.2 Disconnecting means, 692-Lll All conductors, 692.13 Switch or circuit breaker, 692.17 Emergency systems, source of power fo1; 700. 12(G)

NATIONAL ELECTRICAL CODE

2020 Edition

INDEX

Grounding, 692-V Equipment grounding conductor, 692.44, 692.45 Grounding electrode system, 692.47 System grounding, 692.41 Health care facilities, 517.30(B) (2) Marking, 692-VI Fuel cell power sources, 692.53 Fuel shutoff; 692.54 Stored energy, 692.56 Overcurrent protection, 692.9 Standby systems, legally required, 70l.l2(H ) Wiring methods, 692- IV Full-load current motors Alternating current Single-phase, Table 430.248 Three-phase, Table 430.250 Two-phase, Table 430.249 Direcr current, Table 430.247 Furnaces, 422.12 Fusehold ers Caru-idge fuses, 240-Vl Over 1000 volts, 490.2l(B) Plug fuses, 240-V Rating, motor controllers, 430. 90 Size, motor branch circuit protection, 430.57 Type S, 240.53, 240.54 Fuses, ArL 240. See also Hazardous (classified) locations Caru-idge, 240-Vl Disconnection, 240.40 Communications circuits, protectors for, 805. 90(A)

(2) Disconnecting means, 240.40 Electronically actuated, 240.67(B), 240.lOl(A), Table 450.3(A) Note 4 Definition, Art. 100 Enclosures, 240-lll Energy storage systems, 706.31 (E) Generators, constantvol tage, 445.l2(A) Group installation of motors, 430.53(C) Location in circuit, 240.21 Location on premises, 240.24 Markings, 240.60(C) Motor branch circuit protection, 430- N Mmor overload protection, 430.4 Ex.,

2020 Edition

430.28 Ex., 430.225(C) (1) Multiple, see Multiple fuses Network-powered broadband communications circuits, protectors for, 830.90(A)(2) Over 1000 volts, 490.2l(B) Definition, ArL IOO In parallel, not permitted, 240.8, 404.27 Plug, Edison-base type, 240-V Potential (voltage) transformers, 450.3(C) Ratings, 240.6 Service equipment, 230.95(B) Services over !000 volts, 230.208 Switches, arrangement on panel boards with, 408.39 Type S, 240.53, 240.54 Wind electric systems, 694.26 Future expansion and convenien ce, 90.8(A) -G-

Gages (AWG) , conductors, 110.6 Garages, commercial, Art. 511 Battery charging equipment, 511.lO(A) Classification of locations, 51 l.3 Definitions, Art. IOO Electric vehicle charging, 51 l.IO( B) Elevators, dtm1bwaiters, escalators, etc., 620.38 Equipment, 511.4, 511.7 Ground-fault circuit-interrupter protection, 210.8(B) (8), 511.12 Grounding, 250.ll 2(F) Grounding and bonding, 511.16 Locations, .511.4 Major repair, 511.3 Definition, Art. 100 Minor repair, 511.3 Definition, ArL 100 Sealing, 511.9 Special equipment, 51LI0 Ventilation, 5ll.3(C) through (E), Table 51l.3(C) , Table 5ll.3( D) Wiring, 511.4, 51 1.7 Gases, see Hazardous (classified) locations Gasoline bulk storage plants, see Bulk storage p lants; Hazardous (classified) locations Gasoline disp ensing and service stations, see Motor fuel dispensing facilities

NATIONAL ELECTRICAL CODE

Gas pipe As grounding electrode, 250 ..52 (B) (I) General care space, 5 17. 18, 517.29(A), 517 .40 Definition, 517.2 General p rovisions, installatio n of wiring and equipmen t, Art. 110 General requirements for wiring methods, Art. 300. See also Wiring methods Boxes, conduit bodies, or fittings, where required, 300.15 Changing raceway or cable to open wiring, 300.16 Conductors, 300.3 Different systems, 300. 3( C) Installation with other systems, 300.8 Insulated fittings, 300.4(G) Number and sizes of, in raceways, 300.17 Supporting of conductors in vertical raceways, 300.19 Exhaust and ventilating ducts, wiring, 300.22 Expansion joints, raceways, 300.7(B) Free length of wire at outlets, junction and switch points, 300.14 Induced currenrn in ferrous metal enclosures, 300.20 Mechanical and e lectrical continuity, conductors, raceways, cables, 300.10, 300.12, 300.13 Over I 000 volts, ll0-111, 300-11, Art. 490 Protection against Corrosion, 300.6 Physical damage, 300.4 Raceway installations, 300.18 Raceways and cables with other systems, 300.8 Raceways and fittings, metric designator and trade size, 300.1 (C) Raceways as a means of support, 300.ll(C) Raceways exposed to different temperanires, 300.7 Raceways in wet locations above grade, 300.9 Sealing, raceways, change in temperature, 300.7(A) Securing and supporting, 300. 11 Spread of fire or products of combustion, 300.21

Temperature limitations, 3l0.l4(A) (3) Through sn1ds,joists, rafters, 300.4 Underground installations, 300.5, 300.50 Voltage limitations, 300.2 Wiring in ducts, p lenums, airhandling spaces, 300.22 General-use snap switch es, see Snap switches Generating capacity Definition, Art. 100 Generating station Definition, 691.2 Generators, Art. 445 Bushings, 445. 16 Conductot; ampacity of; 445 .1 3 Critical operations power systems, 708.20( F) Disconnecting means, 445.18 Emergency systems, 700.l2(D) Essential electrical systems, task illumination, 5 l 7.33(E), 517.33(F), 517.43(E) Ground-fau lt circuit interrupters, 445.20 Grounding, 250.34, 250.35 Guards for attendants, 445.15 Hazardous (classified) locations, 501.12.1), 502.125, 503.125, 505.16( E) (2), 50.5.22 Health care facilities, 5l 7.30(B) , 517.33(E), 517.33(F), 517.41 lnterconneCLed electric power production sources, 705 .6, 705. 14, 705.30( B), 705.30( D) Legally required standby systems, 701.1 2(D) Listing, 445.6 Location, 44.5.10 Marking, 445. l l Overcurrent protection, 445.12 Portable, 250.34, 702. 12, 708. 12, 708.20( F) Protection of live parts, 445.14 Recreational vehicles, 55 1.30 Standby systems, Art. 701, 702 Fire pump, on-site, 695.3(B) (2), 695.3(D), 69.5.4(B) , 695.6(C) Ex. 2 Terminal housings, 445. 17 Goosenecks, service cables, 230.54 Grid bus rail, 393.104(B) Definition, 393.2 Grooves, cables and raceways ins talled in, 300.4 (F)

70-867

NATIONAL ELECTRICAL CODE

Ground Definition, Art. 100 VolLage LO Definition, Art. 100 Ground clamps, 250.10, 250.70 Grounded Definition, Art. 100 Functionally, 712 ..52(B), 712.55 Definition, 690.2, 712.2 Reference-grounded DC system, 712.30, 712.35, 712.52(B) , 712.55 DefiniLion, 712.2 ResisLively, 712.30, 712.35 Solidly, l 10.54(A) Definition, Art. 100 Three-wire DC sysLem, 712.35 Definition, 712.2 Two-wire DC system, 712.35 DefiniLion, 712.2 Grounded conductors, see also Neulral Al Lerna ting currenl sysLems, 250.24 lhrough 2.50.26 Identification, 200.6, 200.7, 210.5(A) Continuity of, 300.1 3(B) Definilion, Art. LOO Differenl systems, 200.6(D) Electrode-type boilers, over 1000 volrs, 490.72(E) Energy storage systems, 706.30 (C) Fial conductors, nonmetallic extensions, 382. l 04(B) Fuses in, 430.36 Insulated, 200.2(A), 55L54(C), 5.52.55(C) Minimum rating and size, 215.2(A) (2) Mobile homes, 550.16(A) Motor controllers, 430.85 Overcurrent protection, 230.90(B), 240.22 Panelboards, Lermination in, 408.41 Park trailers, 552.5.5 (C) Recreational vehicles, 55 l.54(C) Recreational vehicle site supply equipment, 551.76(D) Separately derived systems, 250.30(A) Services Disconnection of; 230.75 Ground-fault circuit conductor, 250.186(A) Overcurrent protection, 230.90(B)

70-868

Single-phase dwellings, 310.12(D) Switches, disconnection, 404.2(B) Use and identification, Art. 200 Ground fault Definition, Art. IOO Ground-fault circuit conductors, 250.186 Ground-fault circuit interrupters Accessory buildings, dwelling units, 210.8(A) (2) Aircrafl hangars, 513.12 Appliances, 210.8(D), 422.5 Bathtubs, hydromassage, 680.71 Carnivals, circuses, fairs, and simi lar evenrs, 525.23 Definition, Art. 100 Electrically operated pool covers, 680.27( B)(2) Electric signs, portable or mobile, 600.IO(C) (2) Electric vehicle charging systems, 625.54, 625.60( D) Electrified truck parking space supply equipment, 626.24(D) Elevators, d umbwaiters, escalators, etc., 620.6 Fixed electric space-heating equipment, 424.44(E), 424.45(E), 424.99(B)(5) Fountains, 680.51 (A) Garages Commercial, 511.12 Dwelling unirs, 210.8(A) (2) Generators, 44.5.20 Naturally and artificially made bodies of wate1; e lectrical equipment for, 682.15 Permitted uses, 210.8, 215.9 Personnel, protection for, 426.32 Receptacles, 210.8 Appliances, 210.8(D) Bathrooms in dwelling unirs, 210.8(A) (1) Bathrooms in other than dwelling units, 210.8(B) (1)

Conslruction sites, at, 590.6 Equipment requiring servicing, 210.8( E) Fountains, 680.57( B), 680.58 Garages, in dwelling units, 210.8(A) (2) Health care faci lities, .517.20(A), 517.21 Ki tchens in dwelling units, 210.8(A) (6)

Marinas, boatyards, floaLing buildings, and docking facilities, 555.33(B) ( 1), 555.35 Mobile homes, 550.13( B), 550.32(E) Outdoor, 210.8(A) (3), 210.8(B) (4), 210.8(F) Park trailers, .552.41 (C) Pools, 680.5, 680.6, 680.22(A) (4), 680.22(A)(5), 680.22(B) (4), 680.32, 680.62(E) Recreational vehicles, 551.40 (C), 551.41 (C) Replacement, 406.4(D) Required, 210.8 Rooflops in other lhan dwelling uni rs, 210.8( B) Sensitive electronic equipment, 647.7(A) Spas and hot rubs, 680.43(A), 680.44 Recreational vehicles, 551.71 (F) Relocatable structures, 545.28 Swimming pools, see Swimming pools, fountains, and similar installations Ground-fault current path Definition, Art. 100 Ground-fault detection equipment, 712.55 Ground-fau lt protection Connections at services, 230.82 Cranes and hoistS, 610.42 Critical operations power systems, 708.52 Deicing and snow-melting equipment, 426.28 Emergency systems, 700.31 Equipment, 210. 13, 215 .10, 240.13 Definition, Art. 100 Fire pumps, 695.6(G) Floating bui ldings, 555.53 Health care facilities, 517.17 Interconnected e lectric power production sources, 705.11 (E) Legally required standby systems, 701.31 Marinas and boatyards, 555.33(B)( l ), 555.35, 555.53 Motors, 430- IV, 430-V, 4'.~0. 1 30 Personnel, .see Ground-fault circuit interrupters Pipeline heaters, 427.22, 427.27 Service disconnecting means, 230.95

Solar photovoltaic sysLems, 690.41 (B) Temporary installations, 590.6 Grounding, Art. 250 AC systems, 250.20, 250.24 through 250.26 Agricultural buildings, 547.9 Air-conditioning units, 250. 114 Anesthetizing locaLions, 517.62 Antenna, 810. 15, 8 10.21, 810.58, 810.7l( B) Appliances, 250.114 Audio signal processing, amplification, and reproduction equipment, 640.7 Bonding, see Bonding Bulk storage p lan rs, 515.16 Busways, 368.60 Over 1000 volts, 368.260 Cablebus, 370.60 Capacitors, 460.10, 460.27 CATV systems, 820.93, 820-IV Circuirs, 250-1 Less than 50 vol rs, 250.20(A) Clolhes dryers, 250.11 4, 250.140 Clothes washers, 250.114 Communications systems, 800.49, 800. 106(A), 800-1 11 Continuity, 250.96 Contro l, radio equipment, 810.71 (B) Contro l panels, 409.60 Cranes and hoists, 610-Vll DC systems, 250.1 62, 250. 164 Deicing, snow-melting systems, 426.22(A), 426.27, 426.44 Direct current microgrid systems, 71 2.52 Dishwashers, 250.1 14 Electric vehicles, wireless power transfer equipment, 625.101 Electrode system, 250- ILI Elevators, 250.112(E), 250.116, 250. 136, 620-IX Enclosures, 250.64(D), 250.64(E), 250-!V Equipment, cord-and-p lugconnected, 250.114 Fire alarm systems, 250.112(1) Fixed equipmenL, 250.1 10, 250.112, 250. 116, 250.134, 250. 136 Electric space-heating equipment, 424.45(F), 424.99(B) (6) Patient care areas, 517.13

NATIONAL ELECTRICAL CODE

2020 Edition

INDEX

Fixed industrial process e lectrode-type boilers, 425.85 Fixtures, lampholders, etc., 410.155( 8 ), 410-V Fountains, 680.54(A), 680.5.5 Freezers, 250.114 Fuel cell systems, 692- V Garages, commercial, 511.16 Generators, 250.34 Hazardous (classified) locations, 501.30, 502.30, 503.30, 50.5.25, 506.25 Health care faci lities, 517.13, 517.19 High density polyethylene conduit, 353.60 Induction and dielectric heating equipment, 665- 11 Information technology eq uipment, 645.14, 645.15 Instrument transformers, relays, etc., 250- X Intrinsically safe systems, 504.50 Irrigation machines, 675.11 (C), 675.12, 675.13 Lightning surge arresters, 242. 12 Manufacnired buildings, 545.11 Metal boxes, 314.4, 314.40( D) Metal enclosures for conductors, 250.80, 250.86 Metal faceplates, 404.9( 8 ) , 406.6(8) Metal siding, 250. I 16 IN Methods, 250- VII Mobile homes, 550.16 More than 1000 vo lts between conductors, 300.40 Motion picrure srudios, 530.20 Motor fuel dispensing facilities, 514.16 Motors and controllers, 250-VI, 430.12(E ), 430.96, 430- XHI Narurally and artificially made bodies of water, e lectrical equipment for, 682-lll Nonelectrical equipment, 250.116 Organs, 6.50.5 Over 1000 volts, 250-X, 300.40, 490.36, 490.37 Panelboards, 408.40, 517.19(E) Patient care spaces, 517.13 Patient care vicinity, 517.l 9( D) Portable equipment, 250.114 Radio and television equipment, 810.7, 810.15 , 810.20(C),

2020 Edition

810.21, 810.58, 810.71( 8 ) Ranges and similar appliances, 250.140 Receptacles, 250.146, 250.148, 406.4, .517.13, 517.19( H) Recreational vehicles, 551.54, 551.55, 551.76 Refrigerators, 250.114 Relocatable structures, feeders in, 545.22(D) Resistors and reactors over 1000 volts, 470 .19 Sensitive electronic equipment, 647.6 Separate bui ldings, 250.32 Separately derived systems, 250.2l(A), 250.30 Signs and oud ine lighting, 600.7(A), 600.24(B), 600.33(D) Solar photovoltaic signs, 600.34( D) Spas and tubs, 680.6, 680.8(8), 680.43(F) Spray application, dipping, coating, and printing processes, 516. IO(A) (6), 516.16 Substations, 250. 191, 250.194 Surge arresters, 242.12 Swimming pools, 680.6, 680.8(B), 680.23(B) (3), 680.23( 8 ) (4), 680.23(F) (2), 680.24(D), 680.24(F) Switchboards, 250.l 12(A), 408.22 Switches, 404.9(8 ), 404.12 Systems, 250-1, 250-11, 645.14 Theaters and similar locations, 520.81 Tools, motor operated, 250. 114 Transformers, 450.5, 450.6(C) , 450.10 Welders, electric, 630.15 Wind electric systems, 694-V X-ray equipment, 517.78, 660-IV Grounding conductors, 250-Ill, 250-VI; see also Equipment grounding conductors; Grounding e lectrode conductors Eard1 as, 250.4(A)(5), 250 .54 Enclosures, 250- IV Flat conductors, nonmetall ic extensions, 382.104(C) Identification, multiconductor cable, 250.119 Installation, 250.64, 250.120 Materia l, 250.62

NATIONAL ELECTRICAL CODE

Objectionable current over, 2.50.6 Restricted use, 250.121 Sizes, 250.122 Grounding electrode conductors, see also Electrodes, grounding Communications circuits, 800.49, 800. 100 Connection to e lectrodes, 250-1, 250.24( D), 250-Ill Definition, Art. 100 Installation, 250.64 lntersystem, connecting, 250.94 Material, 250.62 Optical fiber cables, 760. 180, 770.100 Radio and television equipment, 810.21, 810.58 Separately d erived systems, 250.30 Sizing, 250.30(A) (6) (a), 250.66, 250.166 Solar photovoltaic systems, 690.47 Surge-protective devices, 242.32, 242.56 Systems and circuits over l kV, 250.l 90 (B) Wind electric systems, 694.40(8) Grounding electrodes, see Electrodes, grotmding Grounding point Patient equipment, 517.19(D) Definition, 517.2 Reference, 517.19, .517.82(8 ), 517.160 (A) (2) Definition, 517.2 Grounding-type attachment plugs, 406.l 0 Ground ring, 250.52(A)(4), 250.53(F), 250.66(C), 250.166(E ) Grouped cables or conductors, 520.54(C), 620.21 (A), 620 .44, 640.8, 650.6, 690.31 (8 ) (2) Definition, 520.2 Grouping, switches, circuit breakers, 404 .8. See also Accessible Grouping of disconnects, 230.72 Group installation, motors, see Motors, grouped Guar ded Defin ition, An. 100 Guarding, guards, see also Enclosures Cables Coaxial, 820. IOO(B)

Flat conductor cable (Type FCC), 324.40(C), 324.40(E), 324. IOO(B) Definition, 324.2 Over 1000 volts, requirements for, 300.40 Portable, 400.32 Circuit breaker handles, 240.41 (8 ) Conductors, con tact, 610.21 (A) Connectors, solar photovoltaic systems, 690.33(B) Construction sites, 590.7 Elevators, dumbwaiters, escalators, etc., 620.71 Generators, 445.15 Grounding, 2.50.l 90(C) (2) Induction and d ielectric heating equipment, 665-11 Intrinsically safe apparatus, cable shields fo1; 504.50 (B) Lan1ps, meaters, dressing rooms, etc., 520.44(A), 520.47, 520.65, 520.72 Live parts, 110.27 Elevators, dumbwaiters, escalators, etc., 620.5(B) Manholes, nmnels, and vaults, 11 0.78 In d1eaters, 520.7 Luminaires, agricultural buildings, 547.8( 8 ) Motion p icture studios, 530.15 Motors and motor controllers, 430-Xll Over 600 volts, 400.32, 590.7 Over 1000volts,l 10.33(A) , 110.34 Service equipment, carnivals, circuses, and fairs, 52.5.l O(A) Transformers, 450.8 Ventilation openings, 11 0.78 X-ray installations, 5 17.78, 660-IV Guest rooms or suites Arc,fault circuit-interrupter protection, 210. 12(C) Branch-circuit voltages, 210.6(A) Cooking equipment, branch circuits for, 210. 17 Defi n ition,Art.100 Outlets, 210.60, 210.70( B), 220.1 4(M) Overcurrent de\~ces, 240.24(E) Tan1per-resistant receptacles in, 406.12(2) Gutters, auxiliary, see Auxiliary gutters

70-869

NATIONAL ELECTRICAL CODE

-H-

Habitable rooms, 210.70(A) (1), 210.70(B) Definition, Art. LOO Hallways, outlets, 210.52 ( H) Handhole enclosures, sro Enclosures, Handho le enclosures Handlamps, portable, 410.82 Hangars, aircraft, see Aircraft hangars Hazard current Definition, 517.2 Hazardous areas, see Hazardous (classified) locations Hazardous atmospheres, ArL 500 Class l locarions, 500..5(B) C lass II locations, 500.5(C) Class Ill locations, 500.5(D) Groups A through G, 500.6 Specific occupancies, Art. 510 Hazardous (classified) locations, Classes I, II, and Ill, Divisions 1 and 2, An. 500; see also Hazardous (classified) locations, Class I, Zone 0, 1, and 2 locations Aircraft hangars, 513.3 Anesthetizing locations, 517.60(A), 517.61 Bulk storage p lants, 515.3 C lass 1, see Hazardous (classified) locations, Class I C lass 1, Zone 0, 1, and 2, see Hazardous (classified) locations, Class I, Zone 0, 1, and 2 locations C lass 11, see Hazardous (classified) locations, Cla~s

II

C lass 111, see Hazardous (classified) locations, Class Ill Combustible gas detection system, 500.7(K) Dust-ignition proof, 500.7(B) Dusts, explosive, Art. 502 Dusttight, 500.7(C) Equipment, 500.8 Approval for class and properties, 500.8(B) Marking, .500.8(C) Optical fiber cable, 500.8(F) Suitabiliry, 500.8(A) Temperature marking, 500.8(D) Threading, 500.8(E)

70-870

Explosion proof equipment, 500.7(A) Fibers/ flyings, lint, highly combustible material, ArL 503, Art. 506 Flammable liquids, ArL 500, Art. 501 Garages, commercial, 511.3, 511.4 Gases, flammable, Art. 500, Art. 501 Gaso line service stations, see Motor fuel dispensing facilities General, 500.4 Group classifications, 500.6 Hoists, 503.155 Inhalation anesthetizing locations, sro Anesthetizing locations Inu-insic safety, 500.7 (E). See alw Intrinsically safe systems Lighting systems, less than 30 volts, 411.8 Material groups, 500.6 Protection techniques, 500. 7 Specific occupancies, ArL 510 Vapors, fl ammable, ArL 500, Art. 501 Hazardous (classified ) locations, Class I, 500.5(B), 500.6(A) , An. 501; see also Hazardous (classified) locations, Classes I, II, and Ill, Divisions l and 2; Hazardous (classified) locations, Class I, Zone 0, I, and 2 locations Bonding, 50l.30(A), 504.60 Circuit breakers, 50 l.115, 501.135 (B) (3) Conu-ol u-ansformers and resistors, 501.105( B) (3), 501.120 Cranes and hoists, 6I0.3(A)(l) Drainage of equipment, 50l.15(F) Ex posed parts, 501.25 Flexible cords, 501.140 Fuses, 50l.l15, 501.135 (B) (3) Grounding, 501.30 Hermetically sealed, 500.70) Induction and dielectric heating equipment, 665.4 Luminaires, 50 l.130 Metal-clad cables, 3 30.130 Meters, instruments, and relays, 501.105 Moror controllers, 501.115 Motors and generators, 501.125

Nonincendive circuit, 500.7(F) Nonincendive component, 500.7( H) Nonincendive equipment, 500.7(G) Oil immersion, 500.7(1) Process sealing, 501.17 Receptacles and attachment plugs, 50 l.l 45 Sealing, 501.15, 50 l.17 Signaling, alarm, remotecontrol, and communications systems, 501.150 Surge protection, 501.35 Switches, 501.ll5, 501.l30(B) (5) , 50l.13.5(B) (3) Transformers and capacitors, 50 l.l 00 Uti lization equipment, 501.135 Wiring methods, 501.10 Zone 0, l, and 2 locations, see Hazardous (classified) locations, Class I, Zone 0, I, and 2 locations Zone equipment, 501.5 Hazardous (classified ) locations, Class I, Zone 0, 1, and 2 locations, Art. 505 Bonding, 50.5 .25(A) Class I, Zone 0, I, and 2 group cla~sifications, 505.6(A) d1rough (C) Classification of locations, 505.5 Class 1, Zone 0, 505 .5(B) (I) Class I, Zone I, 505.5(B) (2) Class I, Zone 2, 505.5(B) (3) Conductors and conductor insulator, 505.18 Documentation, 505.4 Equipment construction, 505.9 Class I temperature, 505.9(D) Listing, 505.9(B) Marking, 505.9(C) Optical fiber cable, 505.9(F) Suitabiliry, 505.9(A) Threading, 505.9(E) Equipment for use in, 505.20 Exposed parts, 505.19 Flexible cords, 505.17 Grounding, 505.25 Material groups, 505 .6 Process sealing, 505.26 Protection techniques, 505.8 Combustible gas detection system, 505.8(1) Encapsulation "m'', 505.8(G), .506.8(E) Definition, Art. 100

Flameproof "d'', 505.8(A) Definition, Art. 100 Increased safety "e'', 505.8(F), 505.22 Definition,Art.100 Intrinsic safery "i'', .50.5.8(C), 506.8(C), 506.8(1) Definition, Art. I 00 Liquid immersion "o", 505.8(E) Definition , Art. l 00 Powder filling "q", 505.8(H) Definition, Art. 100 Purged and pressurized, 500.7(D), 501.l25(A) , 505.8(B) Definition, Art. I 00 Type of protection "n", 505.8(D) Definition, Art. 100 Reference standards, 505.4 Sealing Drainage and, 505.16 Process, 505.26 Special precaution, 505.7 Wiring methods, 505.15 Zone equipment, 505 .9(C) (2), Fig. 505.9(C) (2) Hazardous (classified) locations, Class II, 500.5 (C), An..502; see alm Hazardous (classified) locations, Classes l, II, and Ill, Divisions I and 2 Bonding, 502.30(A) Circuit breakers, 502. ll5 Cranes and hoists, 610.3(A) (2) Exposed parts, 502.25 Flexible cords, 502.140 Fuses, 502 .11 5 Grounding, 502.30 Luminaires, 502.130 Motor controllers, 502.115 Motors and generators, 502.125 Receptacles and attachment p lugs, 502.145 Sealing, 502.15 Signaling, a larm, remotecontrol, and communications systems, meters, insu-uments, and relays, 502.150 Surge protection, 502.35 Switches, 502.115 Transformers and capacitors, 502.100 Utilization equipment, 502.1 35 Ventilating piping, 502.128 Wiring methods, 502.10

NATIONAL ELECTRICAL CODE

2020 Edition

INDEX

Zone 20, 21, and 22 locations for flammable dusts, fibers/ flyings, ArL 506 Zone equipment, 502.6 Hazardous (classified) locations, Class Ill, 500.5( D), ArL 503; see also Hazardous (classified) locations, Classes I, II, and III, Divisions l and 2 Bonding, 503.30(A) Circuit breakers, 503.115 Control transformers and resistors, 503.120 Cranes and hoists, 503.155, 610.3(A) (3) Exposed parts, 503.25 Flexib le cords, 503.J 40 Fuses, 503.115 Grounding, 503.30 Luminaires, 503.130 Motor controllers, 503.115 Motors and generators, 503.125 Receptacles and attachment plugs, 503.145 Signaling, a larm, remotecontrol , and local loudspeaker intercommunications, 5 03.1 50 Storage battery charging equipment, 503.160 Switches, 503.115 Transformers and cap acitors, 503.100 Utilization equipment, 503.135 Ventilation piping, .503. 128 Wiring me thods, 503.10 Zone 20, 21, and 22 locations for flammable dusts, fibers/ flyings, Art. 506 Zone equipme n t, 503 .6 Hazardous (classified) locations, specific, Art. 510 Hazardous (classified) locations, Zone 20, 21, and 22, Art. 506 Bonding, 506.25(A) Classification of locations, 506.5 Documentation, 506.4 Equi pment installation, 506.20 Manufacturer's instructions, 506.20(£) Tempera(llre, 506.20(F) Equi pment requirements, 506.9 Listing, 506.9(B) Marking, 506.9(C) Suitability, 506.9(A) Tempe ra(llre, 506.9(D) Threading, 506.9(E) Flexib le cords, 506.17

2020 Edition

Grounding, .506.25 Material groups, 506.6 Protection techniques, 506.8 Dust-ignition proof, 506.8(A) Dusttight, 506.8( D) Encapsulation, 506.8( E) Enclosure, 506.8(G) Intrinsic safety, 506.8(C), 506.8(1) Nonincendive equipment, 506.8(F) Purged and pressurized, 506.8(B), 506.8( H) De finition, Art. 100 Reference standards, 506.4 Sealing, 506.16 Special precautions, 506.7 Wiring methods, 506.15 Zone equipme nt, 506.9(C) (2) Headers Cellular concrete floor raceways, 372 .2, 372.18(A) Cellular metal floor raceways, 374.2, 374.56 Definition, 372.2, 374.2 Health care facilities, Art. 517 Co mmunications, signaling systems, data systems, less than 120 volt~, nominal, 517- Vl Other-than-patient care areas, 517.81 Signal transmission between appliances, 517.82 Definitions, 517.2 Essential electrical systems, 517-III Ambulatory health care centers, 517.45 Clinics, medical and dental offices, and other h ealth care facilities, 517.45 Connections Alte rnate power source, 51 7.35 Equipment branch, 5 17.44 Life safety branc h, 517.43 Critical branc h, 517.32 De fini tion, 517.2 Equipment branch, 517.44 Hospitals, 517.29(A) IN No. l Lite safety branch, 517.32, 517.33 Nursing h omes and limited care faci lities, 517.40 Power sources, 517.35, 517.41 Requirem e n ts, 517.31 Inha lation a nesth etizing locations, 517- lV

NATIONAL ELECTRICAL CODE

Classification, 517.60 Grounded power system s in anesd1etizing locations, 517.63 Grounding, 517.62 Line isolation monitor, 517.160(B) Low-voltage equipment and instruments, 517.64 Wiring and eqttipment, 517.61, 517.160 Isolated power systems, 5 17-VII Anesthetizing locations, 517.63(E ), 517.63(F) Circuits, 517.64(C) Critical care areas, 517.l 9(F), 517.L9(G) Definition, 517 .2 Essential electrical systems, 517.3 l (C)(2) Grounding, 517.l 9(G) Installation, 5 l 7.160(A) Low-voltage equipment, 517.64( B), 517.64(C) Wet procedure loca tions, 517.20(B) X-ray installation, 5 17 .76 Power sources, 517.31 (F) Wiring and protection, 517-11 Anesthetizing locatio ns, 517. 61 Applicability, .517.10 Critical care areas, 517.19 Essential e lectrical systems, 517.31 (C) Fixed e lectrical eqwpment and gro unding of receptacles, 5 17.13 General care areas, 5 17.18 Ge neral installation / consu·uction crite ria, 517.11 Ground-fault circuitinte rrupte r protection, 517.20(A), 517.21 Ground-faul t protection, 517.17 Grounding, 517.1 3 Panelboard bonding, 5 17.14, 517.l 9(E) Receptacles, 517.13, 517.16, 517.19, 517 .31 (E), 517.42(E) Wet locations, 517 .20 Wiring methods, 5 17.12 X-ray installa tions, 517-V Connection to supply circuit, 517.71 Control circuit conductors, 517.74

Disconnecting means, 517.72 Eqwpment installations, 517.75 Guarding and grounding, 517.78 Hig h tension x-ray cables, 517.77 O vercurrent protection, 517.73 Rating of supply conductors, 517.73 Transformers and capaci tors, 517.76 H eater cords, Table 400.4, 422.43(A) H eat generating equipment, see Induction and die lectric heating equipme nt H eating, see also Heating systems; Induction and dielectric heating equipment Dielectric Definition, 66.5.2 Inductio n Definition, 66.5.2 H eating, ventilating and air conditioning (HVAC) systems, Art. 708 H eating appliances, Art. 422; see also Infrared lam p industrial heating appliances; Wate r heaters H eating cables, Art. 424 H eating elements Marking, 422.61 Resistance, see Fixed e lectdc heating equipment for pipelines and vessels; Fixed outdoor electric deicing and snowmelting equipme nt H eating equipment Central, 422.12 Definitions, 665.2 Fixed, see Fixed e lectric heating equipment for p ipelines and vessels; Fixed e lectric space-heating equipment; Fixed o u tdoo r electric deicing and snow-melting equipment Induction and dielectric, see Induction and die lectric heating equipment Outside, 550.20(B) Receptacle outlets, 210.63(A) Swimming pools, see Swim ming pools, fountains, and similar installations H eating panels and h eating panel sets, radiant, see Fixed e lectric space-heati ng

70-871

NATIONAL E LECTRICAL CODE

equipment, Radiant heating panels and heating panel sets Heating systems Definition, 426.2 Impedance, see Fixed e lectric heating equipment for pipelines and vessels; Fixed outdoor electric deicing and snowmelting equipment Induction, see Induction heating systems Skin effect, see Fixed e lectric heating equipment for pipelines and vessels; Fixed outdoor electric deicing and snowmelting equipment Heavy-duty lampholders Branch circuit~, 210.21 (A), 210.23, Table 210.24 Unit loads, 220.14(E) Herme tically sealed , 500.7 (I) Definition, Art. LOO Hermetic refrigerant motorcompressors, see alw Aircondi tion ing and refrigerating equipment Arnpacity and rating, 440.6(A) Definition, An. LOO Marking, 440.4 Rating and interrupting capacity, 440.12(A) High density polyethylene conduit (Type HDPE), Art. 3.53 Bends, 353.24, 353.26, Chap. 9, Table 2 Bushings, 353.46 Construction specifications, 353-111 Definition, 353.2 Grounding, 353.60 Installation, 353-11 J oints, 353.48 Listing, 353.6 Marking, 353.120 Number of conductors, 353.22, Chap. 9, Table l Size, 353.20 Splices and taps, 353.56 Trimming ends, 353.28 Underground installations, Table 300.50 Uses not permitted, 353.12 Uses permitted, 353.10 High-impedance grounded n eutral systems, 200.2(A), 250.20(D), 250.30(A)(3), 250.36, 250.186(A)(4), 2.50.187 Hoists, Art. 610. See also Cranes

70-872

Bonding, 610-\111 Conductors, contact, 610-IU Control, 610-VI Electrolytic cells, 668.32 Flexible cords, 400.lO(A) (5) Grounding, 250.22 (1), 250.112( E), 250.116(1), 610-Vll Hazardous (classified) locations, 503.155 Marina~ and boatyards, 555 .8 Motors and controllers, disconnecting means, 430.112 Ex., 610-1\1 Nameplates, 6l0.14(G) Overcurrent protection, 610-V, 610.53 Wiring, 610-11 Hoistways Busways in, 368.12 (B) Cablebus in, 370.12(1) Definition, Art. 100 Flexible metal conduit, 348.20(A) Messenger.supported wiring, 396.12 Surface raceways, 386. 12(4), 388.12(4) Wiring in, 620.21 (A) (1), 620.37, 725.136( H), 760.53(A) (3), 760.130( B) (3), 760.136(F) Hoods, range, cord-and-plugconnected , 422.16( B)(4) Hoods for commercial cooking, lighting in, 410. lO(C) Horticultural lighting, 410-XVI Ground-fault circuit interrupter, 410.184 Grounding, 410.182 Installation, 410.174 Locations not permitted, 410.176 Hospitals, see also Health care facilities Definition, 517.2 Essential e lectrical systems, 517.29 IN(A) No. I Patient care space, see Patient care space Psychiatric Definition, 517.2 Host signs, 600.35(A) Definition, 600.2 Hotels and motels Branch-circuit voltages, guest rooms and suites, 210.6(A)

Lighting load, Table 220.12 Lighting outlets required, 2 I0.70(B) Overcurrent devices, guest rooms and suites, 240.24 (E) Receptacle ground-fault circuit interrupter protection, 210.8( B) Receptacle outlets, guest rooms and sttites, 210.60, 210.70(B), 220.14(M) Hot tubs, see Spas, hot tubs, and immersion pools Houseboats, see Marinas, boatyards, floating buildings, and docking faci lities HVAC systems, Art. 708 Hybrid systems Definition, Art. 100 H ydromassage bathtubs, 680-\111 Definition, 680.2 -I-

Identification, see also Color code; Markings Agricultur-al bui lding distribution points, 547.9(D) Boxes (outlet, device, pull, and junction), 314.44 Branch circuits, 210.5 Critical operations power systems wiring, 708. l O(A) Direct-buried cables, Table 30050 Noted Disconnecting means, 110.22, 230.70(B), 620.51 (D) Service disconnects, 230.2(E) Emergency circuits and systems, 700.1 O(A) Feeders, 215.12 Fixed e lectric space-heating equipment, 424.45(A), 424.58, 424.99(A) Fixed resistance and e lectrode industrial process heating equipment Duct heaters, 425.58 Resistance-type boilers, 425.71 Flexible cords, identified conductors within, 200.6(C), 250.l 19(C), 400.22, 400.23 Grounded conductors, Art. 200, 400.22, 402.8 Grounding-pole, 406. lO(B) High-leg, 110.15, 230.56, 408.3(E)( l ), 408.3(F) .

Intrinsically safe systems, 504.80 Sensitive electric equipment conductors, 647.4(C) Service disconnecting means, 230. 70( B) Switchboards and panelboards, 408.3 (F), 408.4 Ungrounded conductors, 210.5(C), 215. 12(C) Wiring device terminals, 250.126, 504.80 Identified Definition, Art. 100 Illumination, see also Lighting; Luminaires Battery system working spaces, 480.IO(G) Means of egress, 517.33(A), 517.43(A) Modular data centers, 646. 15 Task, 517.34 Definition, 5 17.2 Working spaces, 518.6 Immersible appliances, 422.41 Immersion heaters, cord-and-plugconnected , 422.44 Immersion pools, see Swimming pools, fountains, and similar installations Impedance heating systems, see Fixed electric heating equipment for pipelines and vessels; Fixed outdoor electric d eicing and snow-melting equipment IN, explanatory material, 90.5(C) Incandescent lamps, Art. 410. See also Hazardous (classified) locations Guards Aircraft hangars, 513.7(C) Garages, 511.7(B) Theater dressing rooms, 520.72 Lamp wattage, marking on luminaire (fixture), 410. 120 Medium and mogul bases, 410.103 Signs with lampholders for, 600.4(C) Increased sa fety " e " , 505.8( F) Definition,Art.100 Motors and generators, 505 .22 Independent Cirettits for emergency lighting, 700.17

NATIONAL ELECTRICAL CODE

2020 Edition

INDEX

Supports, sen1ces, over buildings, 230.29 Wiring, emergency circuits, 700.lO( B) X-ray control, 660.24 Individual branch circuits, see Branch circuits, individual Induced currents, metal enclosures, 300.20 Induction and dielectric heating equipment, ArL 66.5 Ampacity of supply conductors, 665.10 Definitions, 665.2 Disconnecting means, 665.12 Guarding, grounding, and labeling, 665-11 Access to interior equipment, 665.22 Capacitors, 665.24 Component interconnection, 665.19 Control panels, 665.21 Enclosures, 665.20 Grounding and bonding, 665.26 Marking, 665.27 Shielding, 66.5.25 Wa rning labels or signs, 665.23 Hazardous (classified) locations, 66.5.4 Output circuits, 665.5 Overcurrent protection, 665.11 Remote control, 665.7 Induction h eating systems, see also Induction and dielectric heating equipment Defini tion, 427.2, 665.2 Fixed equipme nt for pipelines and vessels, 427- V Inductive loads Signs, 600.6( 8 ) Switches, types, ratings, 404.14 Industrial control panels, Art. 409 Arc-flash hazard warning, 110.16 Conductors Busbars, 409.102 Minimum size and ampacity, 409.20 Construction specifications, 409III

Definition, Art. 100 Disconnecting means, 409.30 Enclosures, 409.l 00 Grounding, 409.60 Installation, 409-ll Marking, 409.l 10 Overcurrent protection, 409.21 Sen1ce equipment, 409.108

2020 Edition

Spacing, minimum, 409.106 Wiring space in, 409.104 Industrial equipment limitedpower circuits, 725.l2l (A) Industrial installation, supervised Definition, 240.2 Overcurrent protection, 240VILI

Industrial machinery, Art. 670 Definition, 670.2 Disconnecti ng means, 670.4( B) Nameplates, 670.3 Supply conductors and overcurrent protection, 670.4 Industrial manufacturing system Definition, 670.2 Industrial process heating equipment, fixed , see Fixed resistance and electrode industrial process heating equipment Informational notes, explanatory material, 90.5 (C) Information technology equipment, Art. 645 Class 2 and C lass 3 circuits, power source for, 725 .121 (A) D efinitions, Art. 100, 645.2 Disconnecti ng means, 645.4(1) , 645. 10 Engineering supervision, 645.2.5 Grounding, 645.14, 645.15 H ealth care facilities, 517- VI Marking, 645.16 Power distribution units, 645.17 Selective coordination, 645.27 Special requirements for information technology equipment rooms, 64.5.4 Supply circuits and interconnecting cables, 645.5 Uninte rruptible power supplies (UPS), 645.l I Information technology equipment rooms Definition, ArL JOO Special requirements, 645.4 Zones, 645.10(A)(3) Definition, 645.2 Informative annexes, 90.5(0 ), Annexes A through J Infrared lamp industrial heating appliances, 422.48, 425.14 Branch circuits, 210.23(C) , 422.11 (C), 424.4(A)

NATIONAL ELECTRICAL CODE

Overcurrent protection, 422.11 (C) Inhalation anesthetizing locations, see Anesthetizing locations Inherently safe optical radiation "op is", 500.7( L), 505.8( K), 506.8(K) Definition, Art. JOO Innerduct, 770.110(A)(3), 770.l l3(E ) Definition, Art. I 00 Inserts Cellu lar metal floor raceways, 374.l8(C) Underfloor raceways, 390.75 ln sight from Air-