Studying The NEC

1
Studying The NEC

• Part I
• Getting to Know the Basics

2
NEC CODE 2005

• Table of Contents
• Chapters 1 through 9 (major categories)
• Articles 90 through 830 (individual subjects)
• Parts (divisions of an Article)
• Sections and Subsections
• Exceptions (Code permissions)
• Fine Print Notes (explanatory material)
• Tables (Code requirements)
• Index
• Annexes (information)

3
The Table of Contents displays the layoutof
the Chapters, Articles, and Parts as well as the
page numbers. Its an excellent resource and
should be referred to periodically to observe the
interrelationship of the various NEC
components.When attempting to locate the rules
for a partic-ular situation, knowledgeable Code
users often go first to the Table of Contents to
quickly find the specific NEC section that
applies. Mike Holts, NEC Index 2005
1.Table of Contents.
4
2. Chapters.
There are nine Chapters, each of which is divided
into Articles. The Articles fall into one of four
groupings General Requirements (Chapters 1
through 4), Specific Requirements (Chapters 5
through 7), Communications Systems (Chapter 8),
and Tables (Chapter 9).

• Chapter 1 General
• Chapter 2 - Wiring and Protection (2 defend and
  Protect)
• Chapter 3 - Wiring Methods and Materials
  (MMs)
• Chapter 4 - Equipment for General Use
• Chapter 5 - Special Occupancies
• Chapter 6 - Special Equipment
• Chapter 7 - Special Conditions
• Chapter 8 - Communications Systems
  (Telephone,Data, Satellite, and Cable TV)
• Chapter 9 TablesConductor and Raceway
  Specifications

General
General
Specific
Specific
5
2. Chapters.
There are nine Chapters, each of which is divided
into Articles. The Articles fall into one of four
groupings General Requirements (Chapters 1
through 4), Specific Requirements (Chapters 5
through 7), Communications Systems (Chapter
8),and Tables (Chapter 9).

• Chapter 1 - General
• Chapter 2 - Wiring and Protection
• Chapter 3 - Wiring Methods and Materials
• Chapter 4 - Equipment for General Use
• Chapter 5 - Special Occupancies
• Chapter 6 - Special Equipment
• Chapter 7 - Special Conditions
• Chapter 8 - Communications Systems
  (Telephone,Data, Satellite, and Cable TV)
• Chapter 9 TablesConductor and Raceway
  Specifications

General
Specific
6
The NEC contains approximately 140 Articles,each
of which covers a specific subject. For example
3. Articles.

• Article 110 General Requirements
• Article 250 Grounding
• Article 300 Wiring Methods
• Article 430 Motors
• Article 550 Mobile Homes, Manufactured Homes,
  and Mobile Home Parks.
• Article 680 Swimming Pools, Spas, Hot Tubs,and
  Fountains
• Article 725 Remote-Control, Signaling, and
  Power-Limited Circuits
• Article 800 Communications Systems

7
Larger Articles are subdivided into Parts.
Forexample, Article 110 has been divided into
multipleparts
4. Parts.

• Part I. General (Sections 110.1110.23)
• Part II. 600 Volts, Nominal, or Less
  (110.26110.27)
• Part III. Over 600 Volts, Nominal
  (110.30110.59)

8
5. Sections

• Sections Each NEC rule is called a Code
  Section. A Code Section may be broken down into
  subsections by letters in parentheses (A), (B),
  etc. Numbers in parentheses (1),(2), etc., may
  further break down a subsection, and lowercase
  letters (a), (b), etc., further breaks the rule
  down to the third level.
• For example, the rule requiring all receptacles
  in a dwelling unit bathroom to be GFCI protected
  is contained in Section 210.8(A)(1). Section
  210.8(A)(1) is located in Chapter 2, Article 210,
  Section 8, subsection.
• Many in the industry incorrectly use the term
  Article when referring to a Code Section. For
  example, they say Article 210.8, when they
  should say Section 210.8. Sections come after
  the DOT.

9
Chapter Article PART.Sections, Subsections,Excp,
fpn

• Tables
• Annexes
• Index

10
Article 90
11
IntroductionAnd ground rules
12
Chapter 1
13
Information and Rules for Electrical
Installations
GENERAL
14
Article 100
15
Definitions
Part I. General
Part II. Over 600 Volts
16
Article 110
17
Requirements for
18
Requirements for Electrical Installations

1. General
2. 600 Volts, Nominal, or Less
3. Over 600 Volts, Nominal
4. Tunnel Installations over 600 Volts Nominal
5. Manholes and Other Electric Enclosures Intended
   for Personal Entry, All Voltages

19
Chapter 2
20
W and P
21
Wiring and Protection
22
200210215220225230240250280285
23
200 210 215 220 225 230 240 250 280 285

• Neu
• BC
• FEED
• BC,F,S calcs
• Outside BC,F
• Serv
• Overcur
• GB
• Surg
• TVSSs

Fifteen and Feed begin with F
The Historical Person of Jesus started his
ministry when He was 30. He came to SERVE.
24
200 210 215 220 225 230 240 250 280 285

• Use and Identification of Grounded (Neutral)
  Conductors
• Branch Circuits
• Feeders
• Branch-Circuit, Feeder, and Service Calculations
• Outside Branch Circuit and Feeders
• Services
• Overcurrent Protection
• Grounding and Bonding
• Surge Arrestors
• TVSSs (Transient Voltage Surge Suppressors)

25
Chapter 3
26
Wiring mms
Articles 300-398
0
0
m
Got mms?
27
Wiring methods and materials

• 358 EMT Electrical Metallic Tubing
• 360 FMT Flexible Metallic Tubing
• 362 ENTElectrical Nonmetallic Tubing
• 366 Auxiliary Gutters
• 368 - Busways
• 370 Cable Bus
• 372 Cellular Concrete Floor Raceways
• 374 Cellular Metal Floor Raceways
• 376 Metal Wireways
• 378 - Nonmetallic Wireways
• 380 Multioutlet Assembly
• 382 Nonmetallic Extensions
• 384 Strut-Type Channel Raceways
• 386 Surface Metal Raceways
• 388 Surface Nonmetallic Raceways
• 390 Underfloor Raceways
• 392 Cable Trays
• 394 Concealed Knob-and-Tube Wiring

• 300 Wiring Methods
• 310 Conductors for General Wiring
• 312 Cabinets, Cutout Boxes,MS Enclosures
• 314 Outlet,Device,Pull Junction Boxes
• Conduit Bodies,Fittings,Hand hole
• 320 AC Armored Cable
• 322 FC Flat Cable
• 324 FCC Flat Conductor Cable
• 326 IGS Integrated Gas Spacer
• 328 MV Medium Voltage Cable
• 330 MCMetal-Clad Cable
• 332 MI Mineral-Insulated, Metal-Sheathed
• 334 NM,NMC,NMS Nonmetallic-Sheathed
• 336 TCPower and Control Tray Cable
• 338 SE,USE Service Entrance Cable
• 340 UF Underground Feeder Branch Cir
• 342 IMC Intermediate Metal Conduit
• 344 RMC Rigid Metal Conduit
• 348 FMC Flexible Metal Conduit

28
Chapter 4
29
Equipment for General Use
Articles 400-490

• Chords, Fixture Wires, Switches, Receptacles,
  Plugs, Switch and Panel boards,
• Lamps and Lights, Appliances, Space Heaters,
  Motors, AC and Frig, Generators,Transformers,
  Converters,Capacitors, Resistors, Batteries, etc.
  
• The Stuff you USE every day!

30
Stuff we USE Every Day
Articles 400-490

• 427 - Pipe
• 430 - Motors
• 440 AC and FRIG
• 445 - Gen
• 450 - X
• 455 -Phase
• 460 - Cap
• 470 - Resist
• 480 - Bat
• 490 Equip over 600v

• 400 - Flex
• 402 - Fix
• 404 - Sw
• 406 - Recept
• 408 - Sw Pnl Bds
• 409 ICPs
• 410 - Lum
• 411 - Lts _at_gt30v
• 422 - Appl
• 424 - Space
• 426 - Deicing

31
Stuff we USE Every Day

• 400 - Flexible chords and Cables
• 402 - Fixture Wires
• 404 - Switches
• 406 - Receptacles, Cord Connectors, and
  Attachment Plugs
• 408 - Switchboards and Panelboards
• 409 - Industrial Control Panels
• 410 - Luminaries (Lighting Fixtures)
  Lampholders, and Lamps
• 411 - Lighting Systems Operating at 30 Volts or
  Less
• 422 - Appliances
• 424 - Fixed Electric Space heating Equipment
• 426 - Fixed Outdoor Deicing and Snow Melting
  Equipment

• 427 - Fixed Electric Heating Equipment for
  Pipelines and Vessels
• 430 - Motors, Motor Circiuts and Controllers
• 440 - AC and FRIG Equipment
• 445 - Generators
• 450 - Transformers and Transformer
  Vaults(Including Secondary Ties)
• 455 - Phase Converters
• 460 - Capacitors
• 470 - Resistors and Reactors
• 480 - Storage Batteries
• 490 - Equipment over 600v Nominal

32
Chapter 5
33
SSSSSOOOOO!
Whats Next?
34
-500 to 590- SpecialOccupancies
35
Hazards,Health and Other Things
Generally Speaking, these rules apply to ALL
Three Classes and apply always throughout ALL of
Chapter 5!
G D F

• Class I (Flammable Gases)
• Division 1(proximity-very close) under normal
  conditions
• Divison 2(next area or normally closed
  containers but abnormal conditions), Groups A-D
• Class II (Combustible Dust)
• Division 1 (proximity-very close) under normal
  conditions
• Divison 2(next area or normally closed
  containers but abnormal conditions), Groups E-G
• Class III (Combustible Fibers)
• Division 1 (proximity-very close) under normal
  conditions
• Divison 2(next area or normally closed
  containers but abnormal conditions),

36
Groups

• Class I Group Ratings are from A-D
• A Acetylene
• B Flammable gases, liquids and vapors mixed
  with air (MESG .lt40) 500.6(A)(2). Hydrogen,
  butadiene, ethylene oxide, propylene oxide.
• C - Flammable gases, liquids and vapors mixed
  with air (MESG .gt.40, lt80) 500.6(A)(3). Ethyl
  ether, ethylene, acetaldehyde.
• D - Flammable gases, liquids and vapors mixed
  with air (MESG gt80) 500.6(A)(4). Cyclopropane,
  gasoline, propane, natural gas, methane, benzene,
  butane, and ethane.
• Class II Group Ratings are from E-G
• E Atmospheres containing combustible metal
  dust
• F - Atmospheres containing combustible
  carbonaceous dust more than 8 (ex carbon black,
  charcoal, coal, or coke dust)
• G - Atmospheres containing combustible dusts
  such as flour, grain, wood, or plastic.

Class III has no Groups!
37
The Basics of Hazardous Locations

• Article 500 gives the basic settings and
  definition for what constitutes a hazardous
  location and how they are classified.
• What are dangerous flammable,combust-ible, or
  ignitible products and who decides it?

38
Other Topics Covered in the Basics of Hazardous
Locations of Article 500

• Protection Techniques (500.7)
• (A) Explosion proof
• (B) Dust Ignition proof
• (C) Dusttight
• (D) Purged and Pressurized
• (E) Intrinsic Safety
• (F) Nonincendive Circuit
• (G) Nonincendive Equipment
• (H) Nonincendive Component
• (I) Oil Immersion
• (J) Hermetically Sealed
• (K)Combustible Gas Detection System
• Equipment (500.8)
• (A) Approval for Class and Properties
• (B) Markings
• (C) Temperature
• (D) Treading
• (E) Fiber optic Cable Assembly

(Nonincendive means it will not cause something
to be set on fire)
39
Hazardous Locations (Specific Articles)

• 501- Class I
• 502 - Class II
• 503 Class III
• 504 Intrinsically Safe Systems
• 505 Class I, Zone 0,1,and 2 Locations
• 506 Zone 20,21,22 Combustible Dust, Fibers,
  Flyings
• 510 Hazardous (Classified) Locations
• 511 Commercial Garages, Repairs and Storage
• 513 Aircraft Hangers
• 514 Motor Fuel Dispensing
• 515 Bulk Storage Plants
• 516 Spray Application, Dipping and Coating

40
The Rest of the 500 Series Articles (517-590)
deal with what could be considered hazardous
or Special Occupancies
41
Match the picture with its Article number.

• 517
• 518
• 520
• 525
• 530
• 540

42
Heres how they match up

• 517 Health Care Facilities
• 518 Assembly Occupancies
• 520 - Theaters
• 525 - Carnivals
• 530 Motion Picture Studios
• 540 MP Projection (Film) Rooms

43
Articles 545-590

• 545 Man
• 547 Agri
• 550 Mo
• 551 Rec
• 552 Park
• 553 Flo
• 555 Mar
• 590 Temp

44
Articles 545-590

• 545 Manufactured Buildings
• 547 Agricultural Buildings
• 550 Mobile Homes, Manufactured Homes and Parks
• 551 Recreational Vehicles and RV Parks
• 552 Park Trailers
• 553 Floating Buildings
• 555 Marinas
• 590 Temporary Installations

45
Chapter 6
46
Special Equipment (Modification)
47
Articles 600-695 (Theres only 23)

• 600 E.S.O.L
• 604 ManWirSys
• 605 O.F
• 610 CH
• 620 - El,Dum,Esc,MW,WL,SCL
• 625 - EVChargSys
• 630 - EWelders
• 640 ASP,AR Eq
• 645 - IT
• 647 - SEE
• 650 - PipeO
• 660 X-RE

• 665 IDHE
• 668 - EC
• 669 - Eplate
• 670 - IM
• 675 - EDoCIM
• 680 SPF
• 682 - BODIES
• 685 - IES
• 690 - SPvS
• 692 - FuelCS
• 695 - FPUMPS

48
Articles 600-695

• 665 Induction and Dielectric Heating Equipment
• 668 Electrolytic Cells
• 669 - Electroplating
• 670 Industrial Machinery
• 675 Electrically Driven or Controlled
  Irrigation Machines
• 680 Swimming Pools, Fountains
• 682 Natural Artificial Bodies of Water
• 685 Integrated Electrical Systems
• 690 Solar Photovoltaic Systems
• 692 Fuel Cell Systems
• 695 Fire Pumps

• 600 Electric Signs Outline Lighting
• 604 Manufactured Wiring Systems
• 605 Office Furnishings
• 610 Cranes and Hoists
• 620 - Elevators, Dumbwaiters, Escalators, Moving
  Walks,Wheelchair Lifts, Stairway Chair Lifts
• 625 Electric Vehicle Charging Systems
• 630 Electric Welders
• 640 Audio Signal Processing, Amplification
  Reproduction Equipment
• 645 Information Technology Equipment
• 647 Sensitive Electrical Equipment
• 650 Pipe Organ
• 660 X-Ray Equipment

49
Chapter 7
50
Chapter 7

• SPECIAL CONDITIONS

51
Articles 700-705

• 700 EMERGENCY SYSTEMS
• 701 Legally Required Standby Systems
• 702 Optional Standby Systems
• 705 Interconnected Electric POWER Production

52
SPECIAL CONDITIONS

• Articles 720-780

53
Articles 720-780

• 720 - gt50v
• 725 - Power Limited
• 727 - Instrumentation TC
• 760 - Fire
• 770 - Optical
• 780 - Closed Programmed

Key words to remember.
54
Chapter 8
55
Communication Systems
8
56
Articles 800-830

• 800 Comm Circuits
• 810 Radio TV Equipment
• 820 Comm Antenna Radio TV Distribution Systems
• 830 Network-Powered Broadband Comm Systems

57
Chapter 9
58
Tables

• 1 - Percent X section of Conduit and Tubing
• 2 - Radius Bends of Conduit and Tubing
• 4
• 5
• 5A
• 6
• 7
• 8
• 9