National Electrical Code 2008 Edition

CONTENTS

ARTICLE
90, Introduction,70- 21

Chapter 1 General
100, Definitions, 70-24
I. General, 70-24
II. Over 600 Volts, Nominal, 70-31

110, Requirements for Electrical Installations, 70-32
I. General, 70-32
II. 600 Volts, Nominal, or Less, 70-36
III. Over 600 Volts, Nominal, 70-38
IV. Tunnel Installations over 600 Volts, Nominal, 70-40
V. Manholes and Other Electrical Enclosures Intended for Personnel Entry, All Voltages, 70-41

Chapter 2 Wiring and Protection
200, Use and Identification of Grounded Conductors, 70-43

210, Branch Circuits, 70-45
I. General Provisions, 70-45
II. Branch-Circuit Ratings, 70-49
III. Required Outlets, 70-52

215, Feeders, 70-55

220, Branch-Circuit, Feeder, and Service Calculations, 70-57
I. General, 70-57
II. Branch-Circuit Load Calculations, 70-58
III. Feeder and Service Load Calculations, 70-60
IV. Optional Feeder and Service Load Calculations, 70-62
V. Farm Load Calculations, 70-66

225, Outside Branch Circuits and Feeders, 70-67
I. General, 70-67
II. More Than One Building or Other Structure, 70-32
III. Over 600 Volts, 70-72

230, Services, 70-73
I. General, 70-73
II. Overhead Service-Drop Conductors, 70-74
III. Underground Service-Lateral Conductors, 70-75
IV. Service-Entrance Conductors, 70-76
V. Service Equipment - General, 70-78
VI. Service Equipment - Disconnecting Means, 70-78
VII. Service Equipment - Overcurrent Protection, 70-80
VIII. Services Exceeding 600 Volts, Nominal, 70-81

240, Overcurrent Protection, 70-83
I. General, 70-83
II. Location, 70-86
III. Enclosures, 70-90
IV. Disconnecting and Guarding, 70-90
V. Plug Fuses, Fuseholders, and Adapters, 70-90
VI. Cartridge Fuses and Fuseholders, 70-90
VII. Circuit Breakers, 70-91
VIII. Supervised Industrial Installations, 70-92
IX. Overcurrent Protection over 600 Volts, Nominal, 70-93

250, Grounding and Bonding, 70-94
I. General, 70- 94II. System Grounding, 70-97
III. Grounding Electrode System and Grounding Electrode Conductor, 70-104
IV. Enclosure, Raceway, and Service Cable, 70-109
V. Bonding, 70-109
VI. Equipment Grounding and Equipment Grounding Conductors, 70-113
VII. Methods of Equipment Grounding, 70-117
VIII. Direct-Current Systems, 70-120
IX. Instruments, Meters, and Relays, 70-121
X. Grounding of Systems and Circuits of 1 kV and Over (High Voltage), 70-121

280, Surge Arresters, Over 1 kV
I. General, 70-123
II. Installation, 70-124
III. Connecting Surge Arresters, 70-124

Chapter 3 Wiring Methods and Materials

300, Wiring Methods, 70-126
I. General Requirements, 70-126
II. Requirements for over 600 Volts, Nominal, 70-136

310, Conductors for General Wiring, 70-138

312, Cabinets, Cutout Boxes, and Meter Socket Enclosures, 70-164
I. Installation, 70-164
II. Construction Specifications, 70-165

314, Outlet, Device, Pull, and Junction Boxes; Conduit Bodies; Fittings; and Handhole Enclosures, 70-167
I. Scope and General, 70-167
II. Installation, 70-168
III. Construction Specifications, 70-174
IV. Pull and Junction Boxes for Use on Systems over 600 Volts, Nominal, 70-174

320, Armored Cable: Type AC
I. General, 70-175
II. Installation, 70-175
III. Construction Specifications, 70-177

322, Flat Cable Assemblies: Type FC, 70-177
I. General, 70-177
II. Installation, 70-177
III. Construction, 70-178

324, Flat Conductor Cable: Type FCC, 70-178
I. General, 70-178
II. Installation, 70-178
III. Construction, 70-180

326, Integrated Gas Spacer Cable: Type IGS
I. General, 70-180
II. Installation, 70-180
III. Construction Specifications, 70-181

328, Medium Voltage Cable: Type MV
I. General, 70-181
II. Installation, 70-181
III. Construction Specifications, 70-182

330, Metal-Clad Cable: Type MC, 70-182
I. General, 70-182
II. Installation, 70-182
III. Construction Specifications, 70-183

332, Mineral-Insulated, Metal-Sheathed Cable: Type MI, 70-184
I. General, 70-184
II. Installation, 70-184
III. Construction Specifications, 70-185

334, Nonmetallic-Sheathed Cable: Types NM, NMC, and NMS, 70-185
I. General, 70-185
II. Installation, 70-185
III. Construction Specifications, 70-187

336, Power and Control Tray Cable: Type TC, 70-188
I. General, 70-188
II. Installation, 70-188
III. Construction Specifications, 70-188

338, Service-Entrance Cable: Types SE and USE
I. General, 70-189
II. Installation, 70-189
III. Construction Specifications, 70-190

340, Underground Feeder and Branch-Circuit Cable: Type UF
I. General, 70-190
II. Installation, 70-190
III. Construction Specifications, 70-191

342, Intermediate Metal Conduit: Type IMC, 70-191
I. General, 70-191
II. Installation, 70-191
III. Construction Specifications, 70-192

344, Rigid Metal Conduit: Type RMC, 70-192
I. General, 70-192
II. Installation, 70-193
III. Construction Specifications, 70-194

348, Flexible Metal Conduit: Type FMC, 70-194
I. General, 70-194
II. Installation, 70-195

350, Liquidtight Flexible Metal Conduit: Type LFMC, 70-196
I. General, 70-196
II. Installation, 70-196
III. Construction Specifications, 70-197

352, Rigid Polyvinyl Chloride Conduit: Type PVC, 70-197
I. General, 70-197
II. Installation, 70-197
III. Construction Specifications, 70-200

353, High Density Polyethylene Conduit: Type HDPE Conduit, 70-200
I. General, 70-200
II. Installation, 70-200
III. Construction Specifications, 70-201

354, Nonmetallic Underground Conduit with Conductors: Type NUCC, 70-201
I. General, 70-201
II. Installation, 70-201
III. Construction Specifications, 70-202

355, Reinforced Thermosetting Resin Conduit: Type RTRC, 70-203
I. General, 70-203
II. Installation, 70-203
III. Construction Specifications, 70-204

356, Liquidtight Flexible Nonmetallic Conduit: Type LFNC, 70-205
I. General, 70-205
II. Installation, 70-206
III. Construction Specifications, 70-207

358, Electrical Metallic Tubing: Type EMT, 70-207
I. General, 70-207
II. Installation, 70-207
III. Construction Specifications, 70-208

360, Flexible Metallic Tubing: Type FMT, 70-208
I. General, 70-208
II. Installation, 70-209
III. Construction Specifications, 70-209

362, Integrated Gas Spacer Cable: Type IGS, 70-210
I. General, 70-210
II. Installation, 70-210
III. Construction Specifications, 70-211

366, Auxiliary Gutters, 70-212
I. General, 70-212
II. Installation, 70-212
III. Construction Specifications, 70-213

368, Busways, 70-214
I. General Requirements, 70-214
II. Installation, 70-214
III. Construction, 70-215
IV. Requirements for Over 600 Volts, Nominal, 70-216

370, Cablebus, 70-216

372, Cellular Concrete Floor Raceways, 70-217

374, Cellular Metal Floor Raceways, 70-218
I. Installation, 70-219
II. Construction Specifications, 70-219

376, Metal Wireways, 70-219
I. General, 70-219
II. Installation, 70-219
III. Construction Specifications, 70-220

378, Nonmetallic Wireways, 70-221
I. General, 70-221
II. Installation, 70-221
III. Construction Specifications, 70-222

380, Multioutlet Assembly, 70-222

382, Nonmetallic Extensions, 70-222
I. General, 70-222
II. Installation, 70-223
III. Construction Specifications (Concealable Nonmetallic Extensions Only), 70-224

384, Strut-Type Channel Raceway, 70-224
I. General, 70-224
II. Installation, 70-224
III. Construction Specifications, 70-225

386, Surface Metal Raceways, 70-226
I. General, 70-226
II. Installation, 70-226
III. Construction Specifications, 70-226

388, Surface Nonmetallic Raceways, 70-227
I. General, 70-227
II. Installation, 70-227
III. Construction Specifications, 70-227

390, Underfloor Raceways, 70-228

392, Cable Trays, 70-229

394, Concealed Knob-and- Tube Wiring, 70-235
I. General, 70-235
II. Installation, 70-236
III. Construction Specifications, 70-236

396, Messenger-Supported Wiring, 70-237
I. General, 70-237
II. Installation, 70-237

398, Open Wiring on Insulators, 70-237
I. General, 70-237
II. Installation, 70-238
III. Construction Specifications, 70-239

Chapter 4 Equipment for General Use

400, Flexible Cords and Cables, 70-240
I. General, 70-240
II. Construction Specifications, 70-249
III. Portable Cables Over 600 Volts, Nominal, 70-250

402, Fixture Wires, 70-251

404, Switches, 70-255
I. Installation, 70-255
II. Construction Specifications, 70-258

406, Receptacles, Cord Connectors, and Attachment Plugs (Caps), 70-258

408, Switchboards and Panelboards, 70-262
I. General, 70-262
II. Switchboards, 70-263
III. Panelboards, 70-263
IV. Construction Specifications, 70-264

409, Industrial Control Panels, 70-265
I. General, 70-265
II. Installation, 70-266
III. Construction Specifications, 70-266

410, Luminaires, Lampholders, and Lamps, 70-267
I. General, 70-267
II. Luminaire Locations, 70-268
III. Provisions at Luminaire Outlet Boxes, Canopies, and Pans, 70-269
IV. Luminaire Supports, 70-269
V. Grounding, 70-270
VI. Wiring of Luminaires, 70-271
VII. Construction of Luminaires, 70-272
VIII. Installation of Lampholders, 70-273
IX. Construction of Lampholders, 70-273
X. Lamps and Auxiliary Equipment, 70-274
XI. Special Provisions for Flush and Recessed Luminaires, 70-274
XII. Construction of Flush and Recessed Luminaires, 70-274
XIII. Special Provisions for Electric-Discharge Lighting Systems of 1000 Volts or Less, 70-274
XIV. Special Provisions for Electric-Discharge Lighting Systems of More Than 1000 Volts, 70-276
XV. Lighting Track, 70-277
XVI. Decorative Lighting and Similar Accessories, 70-277

411, Lighting Systems Operating at 30 Volts or Less, 70-278

422, Appliances, 70-278
I. General, 70-278
II. Installation, 70-279
III. Disconnecting Means, 70-281
IV. Construction, 70-282
V. Marking, 70-283

424, Fixed Electric Space-Heating Equipment, 70-284
I. General, 70-284
II. Installation, 70-284
III. Control and Protection of Fixed Electric Space-Heating Equipment, 70-284
IV. Marking of Heating Equipment, 70-286
V. Electric Space-Heating Cables, 70-286
VI. Duct Heaters, 70-288
VII. Resistance-Type Boilers, 70-289
VIII. Electrode-Type Boilers, 70-290
IX. Electric Radiant Heating Panels and Heating Panel Sets, 70-290

426, Fixed Outdoor Electric Deicing and Snow-Melting Equipment, 70-292
I. General, 70-292
II. Installation, 70-293
III. Resistance Heating Elements, 70-293
IV. Impedance Heating, 70-294
V. Skin-Effect Heating, 70-294
VI. Control and Protection, 70-295

427, Fixed Electric Heating Equipment for Pipelines and Vessels, 70-295
I. General, 70-295
II. Installation, 70-296
III. Resistance Heating Elements, 70-296
IV. Impedance Heating, 70-297
V. Induction Heating, 70-297
VI. Skin-Effect Heating, 70-298
VII. Control and Protection, 70-298

430, Motors, Motor Circuits, and Controllers, 70-298
I. General, 70-298
II. Motor Circuit Conductors, 70-304
III. Motor and Branch-Circuit Short-Circuit Overload Protection, 70-306
IV. Motor Branch-Circuit Short-Circuit and Ground-Fault Protection, 70-310
V. Motor Feeder Short-Circuit and Ground-Fault Protection, 70-313
VI. Motor Control Circuits, 70-313
VII. Motor Controllers, 70-315
IX. Disconnecting Means, 70-317
X. Adjustable-Speed Drive Systems, 70-320
XI. Over 600 Volts, Nominal, 70-321
XII. Protection of Live Parts - -All Voltages, 70-322
XIII. Grounding -- All Voltages, 70-323
XIV. Tables, 70-324

440, Air-Conditioning and Refrigerating Equipment, 70-327
I. General, 70-327
II. Disconnecting Means, 70-329
III. Branch-Circuit Short-Circuit and Ground-Fault Protection, 70-330
IV. Branch-Circuit Conductors, 70-331
V. Controllers for Motor-Compressors, 70-331
VI. Motor-Compressor and Branch-Circuit Overload Protection, 70-332
VII. Provisions for Room Air Conditioners, 70-333

445, Generators, 70-334

450, Transformers and Transformer Vaults (Including Secondary Ties), 70-335
I. General Provisions, 70-335
II. Specific Provisions Applicable to Different Types of Transformers, 70-339
III. Transformer Vaults, 70-341

455, Phase Converters, 70-342
I. General, 70-342
II. Specific Provisions Applicable to Different Types of Phase Converters, 70-343

460, Capacitors, 70-344
I. 600 Volts, Nominal, and Under, 70-344
II. Over 600 Volts, Nominal, 70-344

470, Resistors and Reactors, 70-345
I. 600 Volts, Nominal, and Under, 70-345
II. Over 600 Volts, Nominal, 70-346

480, Storage Batteries, 70-346

490, Equipment, Over 600 Volts, Nominal, 70-347
I. General, 70-347
II. Equipment - Specific Provisions, 70-347
III. Equipment - Metal-Enclosed Power Switchgear and Industrial Control Assemblies Equipment, 70-350
IV. Mobile and Portable Equipment, 70-352
V. Electrode-Type Boilers, 70-352

Chapter 5 Special Occupancies

500, Hazardous (Classified) Locations, Classes I, II, III, Divisions 1 and 2, 70-354

501, Class I Locations, 70-362
I. General, 70-362
II. Wiring, 70-363
III. Equipment, 70-368

503, Class III Locations, 70-378
I. General, 70-378
II. Wiring, 70-378
III. Equipment, 70-379

504, Intrinsically Safe Systems, 70-380

505, Class I, Zone 0, 1, and 2 Locations, 70-380

506, Zone 20, 21, and 22 Locations for Combustible Dusts or Ignitible Fibers/Flyings, 70-398

510, Hazardous (Classified) Locations - Specific, 70-404

511, Commercial Garages, Repair and Storage, 70-404

513, Aircraft Hangars, 70-407

514, Motor Fuel Dispensing Facilities, 70-410

515, Bulk Storage Plants, 70-414

516, Spray Application, Dipping, and Coating Processes, 70-419

517, Health Care Facilities, 70-425
I. General, 70-425
II. Wiring and Protection, 70-427
III. Essential Electrical System, 70-430
IV. Inhalation Anesthetizing Locations, 70-437
V. X-Ray Installations, 70-440
VI. Communications, Signaling Systems, Data Systems, Fire Alarm Systems,
and Systems Less Than 120 Volts, Nominal, 70-441
VII. Isolated Power Systems, 70-442

518, Assembly Occupancies, 70-443

520, Theaters, Audience Areas of Motion Picture and Television Studios,
Performance Areas, and Similar Locations, 70-444
I. General, 70-444
II. Fixed Stage Switchboards, 70-446
III. Fixed Stage Equipment Other Than Switchboards, 70-447
IV. Portable Switchboards on Stage, 70-448
V. Portable Stage Equipment Other Than Switchboards, 70-451
VI. Dressing Rooms, 70-452
VII. Grounding, 70-453

522, Control Systems for Permanent Amusement Attractions, 70-453
I. General, 70-453
II. Control Circuits, 70-453
III. Control Circuit Wiring Methods, 70-454

525, Carnivals, Circuses, Fairs, and Similar Events, 70-455
I. General Requirements, 70-455
II. Power Sources, 70-455
III. Wiring Methods, 70-456
IV. Grounding and Bonding, 70-457

530, Motion Picture and Television Studios and Similar Locations, 70-457
I. General, 70-457
II. Stage or Set, 70-458
III. Dressing Rooms, 70-460
IV. Viewing, Cutting, and Patching Tables, 70-460
V. Cellulose Nitrate Film Storage Vaults, 70-460
VI. Substations, 70-460

540, Motion Picture Projection Rooms, 70-461
I. General, 70-461
II. Equipment and Projectors of the Professional Type, 70-461
III. Nonprofessional Projectors, 70-462
IV. Audio Signal Processing, Amplification, and Reproduction Equipment, 70-462

545, Manufactured Buildings, 70-462

547, Agricultural Buildings, 70-463

550, Mobile Homes, Manufactured Homes, and Mobile Home Parks, 70-466
I. General, 70-466
II. Mobile and Manufactured Homes, 70-467
III. Services and Feeders, 70-464

551, Recreational Vehicles and Recreational Vehicle Parks, 70-475
I. General, 70-475
II. Combination Electrical Systems, 70-477
III. Other Power Sources, 70-477
IV. Nominal 120-Volt or 120/240-Volt Systems, 70-478
V. Factory Tests, 70-485
VI. Recreational Vehicle Parks, 70-485

552. Park Trailers, 70-488
I. General, 70-488
II. Low-Voltage Systems, 70-488
III. Combination Electrical Systems, 70-489
IV. Nominal 120-Volt or 120/240-Volt Systems, 70-490
V. Factory Tests, 70-496

553, Floating Buildings, 70-497
I. General, 70-497
II. Services and Feeders, 70-497
III. Grounding, 70-497

555, Marinas Boatyards, 70-498

590, Temporary Installations, 70-501

Chapter 6 Special Equipment

600, Electric Signs and Outline Lighting, 70-504
I. General, 70-504
II. Field-Installed Skeleton Tubing, 70-508

604, Manufactured Wiring Systems, 70-509

605, Office Furnishings (Consisting of Lighting Accessories and Wired Partitions), 70-510

610, Cranes and Hoists, 70-511
I. General, 70-511
II. Wiring, 70-512
III. Contact Conductors, 70-514
IV. Disconnecting Means, 70-515
V. Overcurrent Protection , 70-515
VI. Control, 70-516
VII. Grounding, 70-516

620, Elevators, Dumbwaiters, Escalators, Moving Walks, Platform Lifts, and Stairway Chairlifts, 70-517
I. General, 70-517
II. Conductors, 70-519
III. Wiring, 70-520
IV. Installation of Conductors, 70-523
V. Traveling Cables, 70-523
VI. Disconnecting Means and Control, 70-524
VII. Overcurrent Protection, 70-526
VIII. Machine Rooms, Control Rooms, Machinery Spaces, and Control Spaces, 70-526
IX. Grounding, 70-527
X. Emergency and Standby Power Systems, 70-527

625, Electric Vehicle Charging System, 70-527
I. General, 70-527
II. Wiring Methods, 70-528
III. Equipment Construction, 70-528
IV. Control and Protection, 70-529
V. Electric Vehicle Supply Equipment Locations, 70-529

626, Electrified Truck Parking Spaces, 70-531
I. General, 70-531
II. Electrified Truck Parking Spaces Electrical Wiring Systems, 70-532
III. Electrified Truck Parking Space Supply Equipment, 70-533
IV. Transport Refrigerated Units (TRUs), 70-535

630, Electric Welders, 70-536
I. General, 70-536
II. Arc Welders, 70-536
III. Resistance Welders, 70-537
IV. Welding Cable, 70-538

640, Audio Signal Processing, Amplification, and Reproduction Equipment, 70-538
I. General, 70-538
II. Permanent Audio System Installations, 70-542
III. Portable and Temporary Audio System Installations, 70-542

645, Information Technology Equipment, 70-544

647, Sensitive Electronic Equipment, 70-546

650, Pipe Organs, 70-547

660, X-Ray Equipment, 70-548
I. General, 70-548
II. Control, 70-549
III. Transformers and Capacitors, 70-549
IV. Guarding and Grounding, 70-549

665, Induction and Dielectric Heating Equipment, 70-550
I. General, 70-550
II. Guarding, Grounding, and Labeling, 70-551

668, Electrolytic Cells, 70-551

669, Electroplating, 70-554

670, Industrial Machinery, 70-555

675, Electrically Driven or Controlled Irrigation Machines, 70-556
I. General, 70-556
II. Center Pivot Irrigation Machines, 70-558

680, Swimming Pools, Fountains, and Similar Installations, 70-558
I. General, 70-558
II. Permanently Installed Pools, 70-561
III. Storable Pools, 70-568
IV. Spas and Hot Tubs, 70-568
V. Fountains, 70-570
VI. Pools and Tubs for Therapeutic Use, 70-572
VII. Hydromassage Bathtubs, 70-572

682, Natural and Artificially Made Bodies of Water, 70-573
I. General, 70-573
II. Installation, 70-573
III. Grounding and Bonding, 70-574

685, Integrated Electrical Systems, 70-575
I. General, 70-575
II. Orderly Shutdown, 70-575

690, Solar Photovoltaic Systems, 70-575
I. General, 70-575
II. Circuit Requirements, 70-578
III. Disconnecting Means, 70-580
IV. Wiring Methods, 70-581
V. Grounding, 70-583
VI. Marking, 70-585
VII. Connection to Other Sources, 70-585
VIII. Storage Batteries, 70-587
IX. Systems over 600 Volts, 70-588

692, Fuel Cell Systems, 70-588
I. General, 70-588
II. Circuit Requirements, 70-589
III. Disconnecting Means, 70-590
IV. Wiring Methods, 70-590
V. Grounding, 70-590
VI. Marking, 70-590
VII. Connection to Other Circuits, 70-590
VIII. Outputs Over 600 Volts, 70-591

695, Fire Pumps, 70-591

Chapter 7 Special Conditions

700, Emergency Systems, 70-596
I. General, 70-596
II. Circuit Wiring, 70-597
III. Sources of Power, 70-598
IV. Emergency System Circuits for Lighting and Power, 70-600
V. Control - Emergency Lighting Circuits, 70-600
VI. Overcurrent Protection, 70-600

701, Legally Required Standby Systems, 70-601
I. General, 70-601
II. Circuit Wiring, 70-601
III. Sources of Power, 70-602
IV. Overcurrent Protection, 70-603

702, Optional Standby Systems, 70-604
I. General, 70-604
II. Circuit Wiring, 70-605
III. Grounding, 70-605
IV. Sources of Power, 70-605

705, Interconnected Electric Power Production Sources, 70-605
I. General, 70-605
II. Utility-Interactive Inverters, 70-608
III. Generators, 70-609

708, Critical Operations Power Systems (COPS), 70-609
I. General, 70-609
II. Circuit Wiring and Equipment, 70-610
III. Power Sources and Connection, 70-612
IV. Overcurrent Protection, 70-613
V. System Performance and Analysis, 70-614

720, Circuits and Equipment Operating at Less Than 50 Volts, 70-614

725, Class 1, Class 2, and Class 3 Remote-Control, Signaling, and Power-Limited Circuits, 70-614
I. General, 70-614
II. Class 1 Circuits, 70-615
III. Class 2 and Class 3 Circuits, 70-617
IV. Listing Requirements, 70-622

727, Instrumentation Tray Cable: Type ITC, 70-624

760, Fire Alarm Systems, 70-625
I. General, 70-625
II. Non-Power-Limited Fire Alarm (NPLFA) Circuits, 70-626
III. Power-Limited Fire Alarm (PLFA) Circuits, 70-628
IV. Listing Requirements, 70-631

770, Optical Fiber Cables and Raceways, 70-633
I. General, 70-633
II. Cables Outside and Entering Buildings, 70-634
III. Protection, 70-635
IV. Grounding Methods, 70-635
V. Installation Methods Within Buildings, 70-636
VI. Listing Requirements, 70-638

Chapter 8 Communications Systems

800, Communications Circuits, 70-640
I. General, 70-640
II. Wires and Cables Outside and Entering Buildings, 70-641
III. Protection, 70-644
IV. Grounding Methods, 70-644
V. Installation Methods Within Buildings, 70-645
VI. Listing Requirements, 70-647

810, Radio and Television Equipment, 70-649
I. General, 70-649
II. Receiving Equipment - Antenna Systems, 70-650
III. Amateur Transmitting and Receiving Stations - Antenna Systems, 70-652
IV. Interior Installation - Transmitting Stations, 70-653

820, Community Antenna Television and Radio Distribution Systems, 70-653
I. General, 70-653
II. Coaxial Cables Outside and Entering Buildings, 70-654
III. Protection, 70-655
IV. Grounding Methods, 70-656
V. Installation Methods Within Buildings, 70-657
VI. Listing Requirements, 70-659

830, Network-Powered Broadband Communications Systems, 70-660
I. General, 70-660
II. Cables Outside and Entering Buildings, 70-662
III. Protection, 70-664
IV. Grounding Methods, 70-666
V. Installation Methods Within Buildings, 70-667
VI. Listing Requirements, 70-669

Copyright © 2007, National Fire Protection Association®. All Rights Reserved

NFPA 70™
National Electrical Code®
2008 Edition

This edition of NFPA 70, National Electrical Code, was prepared by the National Electrical Code Committee and acted on by NFPA at its June Association Technical Meeting held June 3-7, 2007, in Boston, MA. It was issued by the Standards Council on July 26, 2007, with an effective date of August 15, 2007, and supersedes all previous editions.

This edition of NFPA 70 was approved as an American National Standard on August 15, 2007.

History and Development of the National Electrical Code

The National Fire Protection Association has acted as sponsor of the National Electrical Code since 1911. The original Code document was developed in 1897 as a result of the united efforts of various insurance, electrical, architectural, and allied interests.

In accordance with the provisions of the NFPA Regulations Governing Committee Projects, a National Electrical Code Committee Report on Proposals containing proposed amendments to the 2005 National Electrical Code was published by NFPA in July 2006. This report recorded the actions of the various Code-Making Panels and the Correlating Committee of the National Electrical Code Committee on each proposal that had been made to revise the 2005 Code. The report was circulated to all members of the National Electrical Code Committee and was made available to other interested NFPA members and to the public for review and comment. Following the close of the public comment period, the Code-Making Panels met, acted on each comment, and reported their action to the Correlating Committee. NFPA published the National Electrical Code Committee Report on Comments in March 2007, which recorded the actions of the Code-Making Panels and the Correlating Committee on each public comment to the National Electrical Code Committee Report on Proposals. The National Electrical Code Committee Report on Proposals and the National Electrical Code Committee Report on Comments were presented to the 2007 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 Electrical Section Codes and Standards Review Session held at the 2007 NFPA World Safety Conference and Exposition, Section members had opportunity to discuss and review the report of the National Electrical Code Committee prior to the adoption of this edition of the Code by the Association at its 2007 June Technical Session.

This 51st edition supersedes all other previous editions, supplements, and printings dated 1897, 1899, 1901, 1903, 1904, 1905, 1907, 1909, 1911, 1913, 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, and 2005.

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 insurance underwriting, building and facilities construction and management, and product testing and certification.

This 2008 edition includes the following usability features as aids to the user. Changes other than editorial are highlighted with gray shading within sections and with vertical ruling for large blocks of changed or new text and for new tables and changed or new figures. Where one or more complete paragraphs have been deleted, the deletion is indicated by a bullet (·) between the paragraphs that remain. The index now has dictionary-style headers with helpful identifiers at the top of every index page.

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