Audel guide to the 2002 National Electrical Code

Foreword xv Introduction xvii Article Chapter 1 General 1 100 Definitions 1 110 Requirements for Electrical Installations 1 General 1 600 Volts, Nominal or Less 12 Over 600 Volts, Nominal 16 Tunnel Installations Over 600 Volts, Nominal 21 Chapter 2 Wiring Design and Protection 25 200 Use and Identification of Grounded Conductors 25 210 Branch Circuits 30 General Provisions 30 Branch-Circuit Ratings 42 Required Outlets 47 215 Feeders 53 220 Branch-Circuit, Feeder, and Service Calculations 58 General 58 Feeders 61 Optional Calculations for Computing Feeder and Service Loads 68 Method for Computing Farm Loads 72 225 Outside Branch Circuits and Feeders 73 More Than One Building or Structure 81 Over 600 Volts 85 230 Services 85 General 85 Overhead Services 89 iii iv Contents Underground Service—Lateral Conductors 93 Service-Entrance Conductors 95 Service Equipment—General 103 Service Equipment—Disconnecting Means 104 Service Equipment—Overcurrent Protection 111 Service Exceeding 600 Volts, Nominal 116 240 Overcurrent Protection 119 General 119 Location 123 Enclosures 130 Disconnecting and Guarding 130 Plug Fuses, Fuseholders, and Adapters 131 Cartridge Fuses and Fuseholders 133 Circuit Breakers 134 Supervised Industrial Installations 136 Overcurrent Protection Over 600 Volts, Nominal 137 250 Grounding 138 General 138 Circuit and System Grounding 142 Grounding Electrode System and Grounding Electrode Conductor 156 Grounding Conductors 160 Enclosure and Raceway Grounding 168 Bonding 169 Equipment Grounding and Equipment-Grounding Conductors 177 Methods of Equipment Grounding 183 Direct Current Systems 190 Instruments, Meters, and Relays 191 Grounding of Systems and Circuits of 1 kV and Over (High Voltage) 193 280 Surge Arresters 195 General 195 Installation 196 Connecting Surge Arresters 196 Chapter 3 Wiring Methods and Materials 199 300 Wiring Methods 199 General Requirements 199 Requirements for Over 600 Volts, Nominal 217 310 Conductors for General Wiring 219 312 Cabinets and Cutout Boxes 230 Installation 230 Construction Specifications 236 314 Outlet, Device, Pull, and Junction Boxes, Conduit Bodies, and Fittings 236 General 236 Installation 237 Construction Specifications 253 Manholes and Other Electric Enclosures Intended for Personnel Entry 255 Pull and Junction Boxes for Use on Systems Over 600 Volts, Nominal 256 320 Armored Cable: Type AC 258 General 258 Installation 258 Construction 260 322 Flat Cable Assemblies: Type FC 261 Installation 261 Construction 262 324 Flat Conductor Cable: Type FCC 263 General 263 Installation 265 Construction 266 326 Integrated Gas Spacer Cable: Type IGS 267 328 Medium Voltage Cable: Type MV 267 330 Metal-Clad Cable: Type MC 268 General 268 Installation 268 Construction Specifications 270 332 Mineral-Insulated, Metal-Sheathed Cable: Type MI 271 General 271 Contents v vi Contents Installation 272 Construction Specifications 274 334 Nonmetallic-Sheathed Cable: Types NM and NMC 275 General 275 Installation 276 Construction Specifications 279 336 Power and Control Tray Cable: Type TC 279 Installation 279 Construction Specifications 280 338 Service-Entrance Cable: Types SE and USE 281 340 Underground Feeder and Branch-Circuit Cable: Type UF 284 Installation 285 342 Intermediate Metal Conduit 286 General 286 Installation 286 Construction Specifications 289 344 Rigid Metal Conduit 289 Installation 290 Construction Specifications 294 348 Flexible Metal Conduit 295 Installation 295 Installation 298 356 Liquid-Tight Flexible Nonmetallic Conduit 300 Installation 300 352 Rigid Nonmetallic Conduit 302 Installation 302 354 Nonmetallic Underground Conduit with Conductors 305 General 305 Installation 306 Construction 307 358 Electrical Metallic Tubing 307 Installation 307 360 Flexible Metallic Tubing 310 Installation 310 362 Electrical Nonmetallic Tubing 311 General 311 Installation 311 366 Auxiliary Gutters 314 368 Busways 318 General Requirements 318 Requirements for over 600 Volts, Nominal 322 370 Cablebus 324 372 Cellular Concrete Floor Raceways 326 374 Cellular Metal Floor Raceways 326 Installation 327 376 Metal Wireways 329 Installation 329 378 Nonmetallic Wireways 331 Installation 332 380 Multioutlet Assembly 333 Installation 334 382 Nonmetallic Extensions 335 Installation 335 386 Surface Metal Raceways 341 Installation 341 388 Surface Nonmetallic Raceways 343 Installation 343 Construction Specifications 344 390 Underfloor Raceways 344 392 Cable Trays 349 394 Concealed Knob-and-Tube Wiring 364 396 Messenger-Supported Wiring 367 398 Open Wiring on Insulators 369 Chapter 4 Equipment for General Use 373 400 Flexible Cords and Cables 373 General 373 Construction Specifications 377 Portable Cables Over 600 Volts, Nominal 377 Contents vii viii Contents 402 Fixture Wires 378 404 Switches 380 Installation 380 Construction Specifications 388 408 Switchboards and Panelboards 388 Panelboards 392 Construction Specifications 397 410 Lighting Fixtures, Lampholders, Lamps, Receptacles, and Rosettes 397 General 397 Fixture Locations 398 Provisions at Fixture Outlet Boxes, Canopies, and Pans 401 Fixture Supports 403 Grounding 405 Wiring of Fixtures 406 Construction of Fixtures 410 Installation of Lampholders 410 Construction of Lampholders 411 Lamps and Auxiliary Equipment 411 Receptacles, Cord Connectors, and Attachment Plugs (Caps) 411 Special Provisions for Flush and Recessed Fixtures 415 Construction of Flush and Recessed Fixtures 417 Special Provisions for Electric-Discharge Lighting Systems of 1000 Volts or Less 417 Special Provisions for Electric-Discharge Lighting Systems of More Than 1000 Volts 420 Lighting Track 422 422 Appliances 424 General 424 Branch-Circuit Requirements 424 Installation of Appliances 425 Control and Protection of Appliances 430 Marking of Appliances 433 424 Fixed Electrical Space-Heating Equipment 433 General 433 Installation 434 Control and Protection of Fixed Electric Space-Heating Equipment 435 Marking of Heating Equipment 439 Electric Space-Heating Cables 440 Duct Heaters 446 Resistance-Type Boilers 447 Electrode-Type Boilers 450 Electric Radiant Heating Panels and Heating Panel Sets 451 426 Fixed Outdoor Electric De-icing and Snow-Melting Equipment 455 General 455 Installation 456 Resistance Heating Elements 457 Impedance Heating 460 Skin-Effect Heating 461 Control and Protection 461 427 Fixed Electric Heating Equipment for Pipelines and Vessels 463 General 463 Installation 464 Resistance Heating Elements 465 Impedance Heating 466 Induction Heating 467 Skin-Effect Heating 467 Control and Protection 468 430 Motors, Motor Circuits, and Controllers 469 General 469 Motor Circuit Conductors 478 Motor and Branch-Circuit Overload Protection 483 Motor Branch-Circuit Short-Circuit and Ground-Fault Protection 490 Motor Feeder Short-Circuit and Ground-Fault Protection 495 Contents ix x Contents Motor Control Circuits 497 Motor Controllers 500 Motor Control Centers 504 Disconnecting Means 505 Over 600 Volts, Nominal 510 Protection of Live Parts—All Voltages 512 Grounding All Voltages 513 440 Air-Conditioning and Refrigerating Equipment 515 General 515 Disconnecting Means 519 Branch-Circuit, Short-Circuit, and Ground-Fault Protection 522 Branch-Circuit Conductors 524 Controllers for Motor-Compressors 525 Motor-Compressor and Branch-Circuit Overload Protection 526 Provisions for Room Air-Conditioners 528 445 Generators 530 450 Transformers and Transformer Vaults (Including Secondary Ties) 532 General Provisions 533 Specific Provision Applicable to Different Types of Transformers 545 Transformer Vaults 549 460 Capacitors 552 600 Volts, Nominal and Under 552 Over 600 Volts, Nominal 554 470 Resistors and Reactors 556 480 Storage Batteries 556 490 Equipment Over 600 Volts, Nominal 558 General 558 Equipment—Specific Provisions 560 Equipment—Metal-Enclosed Power Switchgear and Industrial Control Assemblies 565 Mobile and Portable Equipment 565 Chapter 5 Special Occupancies 567 500 Hazardous (Classified) Locations 567 501 Class I Locations 576 502 Class II Locations 595 503 Class III Locations 611 504 Intrinsically Safe Systems 617 505 Class I, Zone 0, 1, and 2 Locations 620 510 Hazardous (Classified) Locations—Specific 620 511 Commercial Garages, Repair, and Storage 621 513 Aircraft Hangars 627 514 Gasoline-Dispensing and Service Stations 632 515 Bulk Storage Plants 637 516 Spray Application, Dipping, and Coating Processes 641 517 Health Care Facilities 646 General 646 Wiring Design and Protection 651 Essential Electrical System 655 Inhalation Anesthetizing Locations 666 X-Ray Equipment 669 Communications, Signaling Systems, Data Systems, Fire Protective Signaling Systems, and Systems Less Than 120 Volts, Nominal 672 Isolated Power Systems 673 518 Places of Assembly 675 520 Theaters and Similar Locations 677 General 677 Fixed Stage Switchboard 678 Stage Equipment—Fixed 680 Portable Switchboards on Stage 682 Stage Equipment—Portable 683 Dressing Rooms 683 Grounding 683 527 Temporary Wiring 684 530 Motion Picture and Television Studios and Similar Locations 687 540 Motion-Picture Projectors 687 Contents xi xii Contents 545 Manufactured Building 687 General 687 547 Agricultural Buildings 689 550 Mobile Homes and Mobile Home Parks 693 General 693 Mobile Homes 698 Services and Feeders 699 551 Recreational Vehicles and Recreational Vehicle Parks 701 553 Floating Buildings 701 555 Marinas and Boatyards 701 Chapter 6 Special Equipment 703 600 Electric Signs and Outline Lighting 703 604 Manufactured Wiring Systems 703 605 Office Furnishings (Consisting of Lighting Accessories and Wired Partitions) 704 610 Cranes and Hoists 707 620 Elevators, Dumbwaiters, Escalators, and Moving Walks 707 630 Electric Welders 707 640 Sound-Recording and Similar Equipment 707 645 Information Technology Equipment 707 650 Organs 710 660 X-Ray Equipment 710 665 Induction and Dielectric Heating Equipment 710 668 Electrolytic Cells 710 669 Electroplating 710 670 Industrial Machinery 710 675 Electrically Driven and Controlled Irrigation Machines 710 680 Swimming Pools, Fountains, and Similar Installations 711 General 711 Permanently Installed Pools 716 Storable Pools 726 Spas and Hot Tubs 727 Fountains 729 Therapeutic Pools and Tubs in Health Care Facilities 732 Hydromassage Bathtubs 734 685 Integrated Electrical Systems 734 General 734 Orderly Shutdown 734 690 Solar Photovoltaic Systems 735 Chapter 7 Special Conditions 737 700 Emergency Systems 737 General 737 Circuit Wiring 740 Sources of Power 741 Emergency Circuits for Lighting and Power 744 Control Emergency Lighting Circuits 745 Overcurrent Protection 746 701 Legally Required Standby Systems 746 General 746 Circuit Wiring 749 Sources of Power 749 Overcurrent Protection 749 702 Optional Standby Systems 749 General 749 Circuit Wiring 751 705 Interconnected Electric Power Production Sources 751 720 Circuits and Equipment Operating at Less Than 50 Volts 752 725 Class 1, Class 2, Class 3, and Class 4 Remote-Control, Signaling, and Power-Limited Circuits 752 General 752 Class 1 Circuits 753 Class 2 and Class 3 Circuits 757 Contents xiii xiv Contents 760 Fire Protective Signaling Systems 759 Scope and General 759 770 Optical Fiber Cables and Raceways 760 780 Closed-Loop and Programmed Power Distribution 764 Chapter 8 Communications Systems 765 800 Communication Circuits 765 810 Radio and Television Equipment 765 820 Community Antenna Television and Radio Distribution Systems 765 Chapter 9 Tables and Examples 767 Annex A 767 Annex B 767 Annex C 767 Annex D 767 Index 769