scope:

(A) Covered This Code covers the installation of electrical conductors, equipment, and raceways; signaling and communications conductors, equipment, and raceways; and optical fiber cables and raceways for the following:

(1) Public and private premises, including buildings, structures, mobile homes, recreational vehicles, and floating buildings

(2) Yards, lots, parking lots, carnivals, and industrial substations

FPN to (2): For additional information concerning such installations in an industrial or multibuilding complex, see ANSI C2-2002, National Electrical Safety Code.

Requirements for locations such as these are found through-out the Code. Specific items such as outside feeders and branch circuits can be found in Article 225, grounding in Article 250, surge arresters in Article 280, switches in Article 404, outside lighting in Article 410, transformers in Article 450, and carnivals in Article 525.

(3) Installations of conductors and equipment that connect to the supply of electricity

Often, but not always, the source of supply of electricity is the serving electric utility. The point of connection from a premises wiring system to a serving electric utility system is, by definition, referred to as the service point. The conductors on the premises side of the service point are, by definition, referred to as service conductors. (These definitions are found in Article 100.) The requirements for service conductors as well as for service-related equipment are found in Article 230. Article 230 applies only where the source of supply of electricity is from a utility.

Where the source of supply of electricity is not the serving electric utility, the source may be a generator, a battery system, a solar photovoltaic system, a fuel cell, or a combination of those sources. Requirements for such sources of supply are found in Article 445 and Articles 700 through 702 for generators, Article 480 for storage batteries, Article 690 for solar photovoltaic systems, and Article 692 for fuel cells. The associated delivery wiring requirements are found in Chapters 2 and 3 (except Article 230) and in Articles 700 through 702 for emergency, legally required, and optional standby power system circuits.

(4) Installations used by the electric utility, such as office buildings, warehouses, garages, machine shops, and recreational buildings, that are not an integral part of a generating plant, substation, or control center.

Section 90.2(A), which was rewritten for the 2002 Code, provides order and clarity concerning the portions of electric utility facilities covered by the NEC. [See 90.2(B) and the related commentary for information on facilities and specific lighting not covered by the NEC.] Exhibit 90.1 illustrates the distinction between electric utility facilities to which the NEC does and does not apply.

Industrial and multibuilding complexes and campus-style wiring often include substations and other installations that employ construction and wiring similar to those of electric utility installations. Although such nonutility installations are within the scope of the NEC, the NEC requirements may not always be all-inclusive, for example, in clearances of conductors or in clearances from buildings or structures for nominal voltages over 600 volts. In such cases, the user can find additional information in the National Electrical Safety Code (NESC), published by the Institute of Electrical and Electronics Engineers, Inc., P.O. Box 1331, 445 Hoes Lane, Piscataway, NJ 08855-1331.

(B) Not Covered This Code does not cover the following:

(1) Installations in ships, watercraft other than floating buildings, railway rolling stock, aircraft, or automotive vehicles other than mobile homes and recreational vehicles

FPN: Although the scope of this Code indicates that the Code does not cover installations in ships, portions of this Code are incorporated by reference into Title 46, Code of Federal Regulations, Parts 110 - 113.

The NEC does not specifically cover shipboard wiring. Title 46 of the Code of Federal Regulations, Parts 110 - 113, however, does contain many specific NEC-referenced requirements. These requirements, which originated in the NEC, are enforced by the U.S. Coast Guard. Installation requirements for floating buildings are covered in the NEC and are found in Article 553.

(2) Installations underground in mines and self-propelled mobile surface mining machinery and its attendant electrical trailing cable

(3) Installations of railways for generation, transformation, transmission, or distribution of power used exclusively for operation of rolling stock or installations used exclusively for signaling and communications purposes

(4) Installations of communications equipment under the exclusive control of communications utilities located outdoors or in building spaces used exclusively for such installations

(5) Installations under the exclusive control of an electric utility where such installations

a. Consist of service drops or service laterals, and associated metering, or

b. Are located in legally established easements, rights-of-way, or by other agreements either designated by or recognized by public service commissions, utility commissions, or other regulatory agencies having jurisdiction for such installations, or

c. Are on property owned or leased by the electric utility for the purpose of communications, metering, generation, control, transformation, transmission, or distribution of electric energy.

FPN to (4) and (5): Examples of utilities may include those entities that are typically designated or recognized by governmental law or regulation by public service/utility commissions and that install, operate, and maintain electric supply (such as generation, transmission, or distribution systems) or communication systems (such as telephone, CATV, Internet, satellite, or data services). Utilities may be subject to compliance with codes and standards covering their regulated activities as adopted under governmental law or regulation. Additional information can be found through consultation with the appropriate governmental bodies, such as state regulatory commissions, Federal Energy Regulatory Commission, and Federal Communications Commission.

An FPN was added to the 2005 Code to clarify the use of the word utility as used in 90.2(B)(4) and 90.2(B)(5). This explanatory information now provides the authority having jurisdiction a basis for judgment concerning this issue.

It is not the intent of 90.2(B)(5) to exclude the NEC as an installation regulatory document. After all, the NEC is fully capable of being utilized for electrical installations in most cases, and 90.2(B)(5) does not pertain to areas where portions of the NEC could not be used. Rather, 90.2(B)(5) lists specific areas where the nature of the installation requires specialized rules or where other installation rules, standards, and guidelines have been developed for specific uses and industries. For example, the electrical utility industry uses the NESC as its primary requirement in the generation, transmission, distribution, and metering of electrical energy. See Exhibit 90.1 for examples of electric utility facilities that may or may not be covered by the Code.

(C) Special Permission The authority having jurisdiction for enforcing this Code may grant exception for the installation of conductors and equipment that are not under the exclusive control of the electric utilities and are used to connect the electric utility supply system to the service-entrance conductors of the premises served, provided such installations are outside a building or terminate immediately inside a building wall.