Answer: The National Fire Protection Association (NFPA) has a free online National Electrical Code viewing-only version. The link is further down below.
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Electrical codes have existed for over one hundred years and continue to evolve and adjust according to human development. The National Electrical Code is updated every three years and establishes additional safe installation practices as more hazards become apparent.
Table of Contents:
Most electrical installations have requirements under more than one free National Electrical Code article. In addition, other building codes may apply to your installation, such as the Fire Code, Sound Code, Mechanical Code, Seismic Code, and local codes and requirements.
When you submit plans and your scope of work to the building department with your permit application, you can ask them what building codes apply to your planned work. Do not be surprised if you don’t get an answer or get a vague response. They are not responsible for teaching you how to do the work correctly.
The responsibility for the installation being done to code is with the contractors working on the job or the homeowner doing their work themself.
Many building code books are readily available at Amazon and some bookstores. The articles suggested below are based on the 2023 National Electrical Code.
Rather than have you spend hours going through the index and table of contents in the free National Electrical Code online version, I have listed some common electrical installations and the specific code references for each.
This is not a substitute for getting your very own code book and reading the applicable chapters for your projects. The free National Electrical Code will not teach you how to install electrical wiring because it is not a substitute for many years of wiring experience.
Many professional electricians also utilize other books such as Ugly’s for their electrical code references, mathematical formulas, conduit bending guide, conduit fill, conversion tables, and transformer and control circuit wiring diagrams.
In addition to the specific code chapters listed further down, almost all electrical installations will be affected by the free National Electrical Code sections underneath this sentence:
Article 210 – Branch Circuits Not Over 1000 Volts ac, 1500 volts dc, Nominal
Article 250 – Grounding and Bonding
Article 300 – General Requirements for Wiring Methods and Materials
Article 310 – Conductors for General Wiring
Article 314 – Outlet, Device, Pull, and Junction Boxes; Conduit Bodies; Fittings; and Handhole Enclosures
The free National Electrical Code (NFPA 70) articles listed below may not be the only electrical and building code articles relevant to your project. It is good to confer with your local building department and get a copy of the code books pertinent to the work that you are planning.
Agricultural Buildings – Article 547
Air Conditioning and Refrigerating Equipment – Article 440
Appliances – Article 422
Basements – Lighting article 210.70(C), Receptacles 210.8(A)(5), 210.52(G)
Bathrooms – Article 410.10(D), Circuits 210.11(C)(3), Lighting 210.70(A)(1), 210.70(B) Receptacles 210.8(A)(1), 210.8(B)(1), 406.9(C), 210.23(B)Exception.
Boats – Marinas, Boatyards, Floating Buildings – Article 555
Bonding – Article 250
Cannabis Oil Equipment and Systems – Article 512
Ceiling Fans – Article 314.27(C), 422.18, 680.22(B), 680.43(B)
Definitions – Article 100
Electric Vehicles – Article 625
Electrical Box Fill – An electrical box is only allowed to have a certain amount of wires in it according to its size. Many electrical boxes have their cubic inch capacity stamped into them. Plastic boxes also tell you the number of wires allowed. A wiring device such as a switch or an outlet counts as two wires. See article 314.16 and tables 314.16(A), 314.16(B)(1)
Electrically Metallic Tubing (EMT) Conduit – Article 358, table 300.5(A)
Electrical Nonmetallic Tubing (ENT) – Sometimes called Smurf tubing due to its blue color. Article 362.
Flexible Cords and Flexible Cables – Extension cords, appliance cords, lamp cords, etc. Chapter 4 Article 400.
Flexible Metal Conduit (FMC) – Article 348
Generator, Portable – Articles 445, 702
Generator, standby, permanently installed – Articles 445, 700, 701, and 702
GFCI – Ground Fault Circuit Interrupters – Article 210.8
Grounding – Article 250
Ground Rods – Articles 250.50, 250.54, 250.64
Hot Tubs – Article 680.40, Lighting 411.6(B), GFCI 680.43(A), 680.44
Kitchens – Appliances article 422, AFCI Arc Fault Circuit Interrupters 210.12(B), GFCI Ground Fault Circuit Interrupters 210.8(A)(6), Receptacles 210.52
Knob and Tube Wiring – Article 394. For existing wiring.
Lighting Fixture Installation – Luminaires, Lampholders, and Lamps – Article 410
Liquidtight Flexible Metal Conduit (LFMC) Commonly called Sealtight – Article 350.
Liquidtight Flexible Nonmetallic Conduit (LFNC) – Article 356
Low Voltage Lighting – Article 411
Mobile Homes, Manufactured Homes, and Mobile Home Parks – Article 550
Motors – Article 430
PVC Conduit – Article 352, table 300.5(A)
Receptacles, Cord Connectors, and Attachment Plugs – Article 406
Recreational Vehicles and Recreational Vehicle Parks – Article 551, GFCI 551.40(C), 551.41(C)
Rigid Metal Conduit (RMC) – Article 344, table 300.5(A)
Services – Articles 230, 338, 250.28, 250.24(E), 250.66, table 300.5(A)
Solar Photovoltaic Systems – Article 690
Sub-Panels – Article 408
Surge Protectors – Overvoltage Protection Devices – Articles 242, 230.67
Swimming Pools – Article 680. Bonding 680.26, lighting Article 411.6(B)
Switches – Article 404. Smart switches and electronic dimmers – Article 404.14(F)
Telephone – Articles 800, 805
Temporary Installations – Article 590
Type AC Metal Armored Cable (BX) – Article 320
Type MC Metal Clad Cable – Article 330
Type NM-B Nonmetallic Sheathed Cable (Romex) – Article 334
Type UF Underground Feeder Cable – Article 340, table 300.5(A)
Wire – Article 310 and table 310.16
Wiring Methods – Chapter 3, article 300 – This is a good chapter for installation methods.
Wiremold – Metal Wireways – Article 376 and article 386 Surface Metal Raceways
Wiremold – Nonmetallic Wireways – Article 378 and article 388 Surface Nonmetallic Raceways
The NFPA has a free National Electrical Code (NFPA 70) online version of the current edition and older editions. You can access it by clicking here and then creating a free account. When you get to the page, scroll down a little and click the “Free Access” button. No credit card is required, only an email address.
Electricity can start house fires. Electricity can kill or maim. It is important that when doing electrical work, safety is a major concern. Incorrectly installed wiring is an accident waiting to happen.
Click this link to see many types of wiring methods when working around the home.
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Read my article about the requirements for labeling emergency disconnects.