McGraw-Hill’s NATIONAL ELECTRICAL CODE ® 2008 HANDBOOK About the Authors Brian J. McPartland is an electrical consultant and educator who teaches the nuts and bolts of the National Electrical Code ® . He is coauthor of McGraw-Hill’s National Electrical Code ® Handbook, 25th Edition. Joseph F. McPartland is an electrical contracting consultant and coau- thor of McGraw-Hill’s National Electrical Code ® Handbook, 25th Edition. Frederic P. Hartwell is a working electrician, President of Hartwell Electrical Services, Inc., and has been certified by the International Association of Electrical Inspectors as a Certified Master Electrical Inspector. He is the senior member of NEC ® CMP 9. He is coauthor of McGraw-Hill’s American Electricians’ Handbook, 15th Edition. NATIONAL ELECTRICAL CODE ® 2008 HANDBOOK Twenty-Sixth Edition Based on the Current 2008 National Electrical Code ® by Brian J. McPartland Joseph F. McPartland and Frederic P. 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Contents Preface xi Introduction to the National Electrical Code ® xiii Brief History of the National Electrical Code ® xv About the 2008 NE Code ® xvii Article Page 90 Introduction 1 Chapter 1 100 Definitions 15 110 Requirements for Electrical Installations 55 Chapter 2 200 Use and Identification of Grounded Conductors 103 210 Branch Circuits 112 215 Feeders 187 220 Branch-Circuit, Feeder, and Service Calculations 209 225 Outside Branch Circuits and Feeders 249 230 Services 262 240 Overcurrent Protection 326 250 Grounding and Bonding 379 v Article Page 280 Surge Arresters, Over 1 kV 531 285 Surge-Protective Devices, 1 kV or Less 534 Chapter 3 300 Wiring Methods 537 310 Conductors for General Wiring 601 312 Cabinets, Cutout Boxes, and Meter Socket Enclosures 635 314 Outlet, Device, Pull, and Junction Boxes; Conduit Bodies; Fittings; and Handhole Enclosures 644 320 Armored Cable: Type AC 686 322 Flat Cable Assemblies: Type FC 693 324 Flat Conductor Cable: Type FCC 695 326 Integrated Gas Spacer Cable: Type IGS 698 328 Medium Voltage Cable: Type MV 699 330 Metal-Clad Cable: Type MC 701 332 Mineral-Insulated, Metal-Sheathed Cable: Type MI 707 334 Nonmetallic-Sheathed Cable: Types NM, NMC, and NMS 711 336 Power and Control Tray Cable: Type TC 721 338 Service-Entrance Cable: Types SE and USE 724 340 Underground Feeder and Branch-Circuit Cable: Type UF 730 342 Intermediate Metal Conduit: Type IMC 734 344 Rigid Metal Conduit: Type RMC 740 348 Flexible Metal Conduit: Type FMC 749 350 Liquidtight Flexible Metal Conduit: Type LFMC 755 352 Rigid Polyvinyl Chloride Conduit: Type PVC 758 353 High Density Polyethylene Conduit: Type HDPE Conduit 767 354 Nonmetallic Underground Conduit with Conductors: Type NUCC 768 355 Reinforced Thermosetting Resin Conduit: Type RTRC 768 356 Liquidtight Flexible Nonmetallic Conduit: Type LFNC 769 358 Electrical Metallic Tubing: Type EMT 770 360 Flexible Metallic Tubing: Type FMT 774 362 Electrical Nonmetallic Tubing: Type ENT 776 366 Auxiliary Gutters 779 368 Busways 782 370 Cablebus 793 372 Cellular Concrete Floor Raceways 795 374 Cellular Metal Floor Raceways 798 376 Metal Wireways 800 378 Nonmetallic Wireways 803 380 Multioutlet Assembly 804 382 Nonmetallic Extensions 804 384 Strut-Type Channel Raceway 805 386 Surface Metal Raceways 806 388 Surface Nonmetallic Raceways 808 390 Underfloor Raceways 808 392 Cable Trays 810 394 Concealed Knob-and-Tube Wiring 824 396 Messenger-Supported Wiring 826 398 Open Wiring on Insulators 826 vi CONTENTS Article Page Chapter 4 400 Flexible Cords and Cables 831 402 Fixture Wires 837 404 Switches 838 406 Receptacles, Cord Connectors, and Attachment Plugs (Caps) 851 408 Switchboards and Panelboards 860 409 Industrial Control Panels 882 410 Luminaires, Lampholders, and Lamps 884 411 Lighting Systems Operating at 30 V or Less 918 422 Appliances 918 424 Fixed Electric Space-Heating Equipment 926 426 Fixed Outdoor Electric Deicing and Snow-Melting Equipment 943 427 Fixed Electric Heating Equipment for Pipelines and Vessels 946 430 Motors, Motor Circuits, and Controllers 948 440 Air-Conditioning and Refrigerating Equipment 1032 445 Generators 1055 450 Transformers and Transformer Vaults (Including Secondary Ties) 1058 455 Phase Converters 1097 460 Capacitors 1099 470 Resistors and Reactors 1110 480 Storage Batteries 1110 490 Equipment Over 600 Volts, Nominal 1113 Chapter 5 500 Hazardous (Classified) Locations, Classes I, II, and III, Divisions 1 and 2 1129 501 Class I Locations 1141 502 Class II Locations 1187 503 Class III Locations 1194 504 Intrinsically Safe Systems 1196 505 Class I, Zone 0, 1, and 2 Locations 1200 506 Zone 20, 21, 22 Locations for Combustible Dusts or Ignitible Fibers/Flyings 1206 510 Hazardous (Classified) Locations—Specific 1206 511 Commercial Garages, Repair and Storage 1207 513 Aircraft Hangars 1210 514 Motor Fuel Dispensing Facilities 1211 515 Bulk Storage Plants 1218 516 Spray Application, Dipping, and Coating Processes 1220 517 Health Care Facilities 1222 518 Assembly Occupancies 1243 520 Theaters, Audience Areas of Motion Picture and Television Studios, Performance Areas, and Similar Locations 1244 522 Control Systems for Permanent Amusement Attractions 1255 525 Carnivals, Circuses, Fairs, and Similar Events 1255 530 Motion Picture and Television Studios and Similar Locations 1257 540 Motion Picture Projection Rooms 1260 545 Manufactured Buildings 1264 547 Agricultural Buildings 1264 550 Mobile Homes, Manufactured Homes, and Mobile Home Parks 1269 CONTENTS vii Article Page 551 Recreational Vehicles and Recreational Vehicle Parks 1273 552 Park Trailers 1275 553 Floating Buildings 1275 555 Marinas and Boatyards 1276 590 Temporary Installations 1282 Chapter 6 600 Electric Signs and Outline Lighting 1297 604 Manufactured Wiring Systems 1303 605 Office Furnishings (Consisting of Lighting Accessories and Wired Partitions) 1305 610 Cranes and Hoists 1307 620 Elevators, Dumbwaiters, Escalators, Moving Walks, Platform Lifts, and Stairway Chair Lifts 1309 625 Electrical Vehicle Charging Systems 1311 626 Electrified Truck Parking Spaces 1314 630 Electric Welders 1317 640 Audio Signal Processing, Amplification, and Reproduction Equipment 1319 645 Information Technology Equipment 1324 647 Sensitive Electronic Equipment 1332 650 Pipe Organs 1336 660 X-Ray Equipment 1336 665 Induction and Dielectric Heating Equipment 1337 668 Electrolytic Cells 1340 669 Electroplating 1343 670 Industrial Machinery 1343 675 Electrically Driven or Controlled Irrigation Machines 1344 680 Swimming Pools, Fountains, and Similar Installations 1346 682 Natural and Artificially Made Bodies of Water 1386 685 Integrated Electrical Systems 1389 690 Solar Photovoltaic Systems 1389 692 Fuel Cell Systems 1403 695 Fire Pumps 1406 Chapter 7 700 Emergency Systems 1417 701 Legally Required Standby Systems 1438 702 Optional Standby Systems 1439 705 Interconnected Electric Power Production Sources 1443 708 Critical Operations Power Systems (COPS) 1447 720 Circuits and Equipment Operating at less than 50 Volts 1450 725 Class 1, Class 2, and Class 3 Remote-Control, Signaling, and Power-Limited Circuits 1451 727 Instrumentation Tray Cable: Type ITC 1473 760 Fire Alarm Systems 1474 770 Optical Fiber Cables and Raceways 1478 780 Closed-Loop and Programmed Power Distribution (Deleted) 1485 viii CONTENTS Article Page Chapter 8 800 Communications Circuits 1487 810 Radio and Television Equipment 1493 820 Community Antenna Television and Radio Distribution Systems 1496 830 Network-Powered Broadband Communications Systems 1501 Chapter 9 Tables 1511 Annex A. Product Safety Standards 1514 Annex B. Application Information for Ampacity Calculation 1515 Annex C. Conduit and Tubing Fill Tables for Conductors and Fixture Wires of the Same Size 1518 Annex D. Examples 1518 Annex E. Types of Construction 1531 Annex F. Availability and Reliability for Operations Power Systems; and Development and Implementation of Functional Performance Tests (FPTS) for Critical Operations Power Systems 1532 Annex G. Supervisory Control and Data Acquisition (SCADA) 1532 Annex H. Administration and Enforcement 1532 Index 1535 CONTENTS ix