Electrical codes

Systematic bodies of rules governing the practical application, installation, and interconnection of electrically operated equipment, devices, and electrical wiring systems.

The basic code used throughout the United States is the National Electrical Code, prepared under the direction of the National Fire Protection Association (NFPA). It is approved by the American National Standards Institute. The National Electrical Code is purely advisory as far as the National Fire Protection Association is concerned, but it is very widely used for legal regulatory purposes, The code is administered by various local inspection agencies, whose decisions govern its application to individual installations. The National Electrical Code is incorporated bodily or by reference in many municipal building ordinances, often with additional provisions or restrictions applicable in the particular locality. Some large cities have independent electrical codes; however, the actual provisions in most such codes tend to be basically similar to the National Electrical Code.

Compliance with the provisions of the code can effectively minimize fire and accident hazards in any electrical design. It sets forth requirements that constitute a minimum standard for the framework of electrical design. As stated in its introduction, the code is concerned with the “practical safeguarding of persons and of buildings and their contents from hazards arising from the use of electricity for light, heat, power, radio, signaling and for other purposes.” The National Electrical Code is recognized as a legal criterion of safe electrical design and installation. It is used in court litigation and by insurance companies as a basis for insuring buildings.

In addition to the National Electrical Code itself, other standards and recommended practices are made available by the National Fire Protection Association. These cover such special subjects as hospital operating rooms, municipal fire alarm systems, garages, aircraft hangars, and other equipment with great potential hazards due to improper design.

The National Electrical Safety Code (to be distinguished from the National Electrical Code) is published by the Institute of Electrical and Electronic Engineers, Inc. This code applies to the outdoor circuits of electric utility companies and to similar systems or equipment on commercial and industrial premises.

Standards on the construction and assembly of many types of electrical equipment, materials, and appliances are set forth in literature issued by the Underwriters’ Laboratories, Inc. The Underwriters’ Laboratories examines, tests, and determines the suitability of materials and equipment to be used according to code regulations.