The NESC is revised every 5 years. The purpose of the NESC is the practical safeguarding of persons during the installation, operation, or maintenance of electrical supply and communication lines, equipment, and associated work practices employed by a public or private electric supply, communications, railway, or similar utility in the exercise of its function as a utility.
It covers similar systems under the control of qualified persons, such as those associated with an industrial complex or utility interactive system. It is not intended as a design specification or as an instruction manual.
What Isn't Covered
NESC rules do not cover installations in mines, ships, railway rolling equipment, aircraft, or automotive equipment, or utilization wiring except as covered in Parts 1 and 3. For building utilization wiring requirements, see the National Electrical Code.
IEEE is currently undertaking a survey of all Public Service Commissions, Public Utility Commissions, or other appropriate state regulatory bodies to determine the edition of the NESC in effect in each state and how that adoption is promulgated.
For specific contact information for each public service or public utility commission, see the listing provided by the National Association of Regulatory Utility Commissioners (NARUC).
How the NESC differs from the National Electric Code® (NEC®)
The NEC, NFPA-70, addresses proper electrical systems and equipment installation to protect people and property from hazards arising from the use of electricity in buildings and structures. This includes:
- Installations of electric conductors and equipment within or on public and private buildings or other structures, including mobile homes, recreational vehicles, and floating buildings; and other premises such as yards, carnivals, parking lots, and industrial substations.
- Installations of conductors and equipment that connect to the supply of electricity.
- Installations of other outside conductors and equipment on the premises.
- Installations of optical fiber cable.
- Installations in buildings 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.