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Section 2 Installation
The National
Electrical Code
The most informative and authoritative
body of information concerning electrical
wiring installation in the United States, and
perhaps the world, is the National Electrical
Code® (NEC). See Figure 4-1. It establishes a set
of rules, regulations, and criteria for the instal-
lation of electrical equipment. Compliance with
these methods will result in a safe installation.
State and Local Codes
Although the NEC, itself, has no legal basis,
it is often made mandatory under local or state
rulings. In such cases it becomes a legal docu-
ment. The authority having jurisdiction (AHJ)
is the person or group of people responsible for
approving the equipment, materials, an installa-
tion, or a procedure. The NEC is not an AHJ, but
the building commission of your municipality
may be the AHJ and will probably use the NEC for
most electrical installations. The phrase “authority
having jurisdiction” is used instead of a specifi c
title, such as electrical inspector or county building
commission, because the approving systems vary.
Code enforcement
Almost every state, region, or locality has
some sort of electrical code. Many use the NEC
in whole or in part. Article 90.4 of the NEC grants
full power to the local inspection authority to
interpret and modify meanings and intentions of
the NEC. Further, some communities add regula-
tions beyond those outlined in the NEC. For these
reasons, the local inspector should be consulted for
a copy of the local codes. Failure to do so will prob-
ably result in violations and an inspection failure.
Inspection, permits, and licensing
In many areas, permits and licensing are
required to do electrical work. In such areas, the
Web Site
www.nfpa.org
For a copy of the National Electrical Code,
visit the Web site of the National Fire Protection
Association or write to:
NFPA
Batterymarch Park
Quincy, MA 02169
The NEC is drafted by a team of experts
assembled for this purpose by the National
Fire Protection Association (NFPA). This team
is formally called the National Electrical Code
committee. They revise and update the NEC
every three years. It is imperative that anyone
installing electrical wiring obtains and studies
the NEC. Articles and sections of the NEC are
referred to throughout this text. Although
certain portions, tables, and examples are
directly quoted from its text, there is so much
useful information in the NEC that not having it
available would be a tremendous hindrance.
National Electrical Code (NEC): The most informative
and authoritative body of information concerning elec-
trical wiring installation in the United States.
authority having jurisdiction (AHJ): The person or
group of people responsible for approving the equip-
ment, materials, an installation, or a procedure.
Figure 4-1. The National Electrical Code is the set of
rules that most installations must follow.
Code Alert
Articles 90, 100, and 110 provide a neces-
sary foundation to the remainder of the Code.
Article 90 informs us of what is and is not
covered in the NEC. Article 100 gives us the
absolute essential defi nitions necessary in
any conversation regarding electricity. Using
inconsistent terms leads to confusion and
misinterpretation. Article 110 is the “road map”
of the Code. Here, we fi nd the general require-
ments for electrical installations and, along
with Articles 90 and 100, a solid footing to fully
understand the rest of the NEC.