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An electrical code is a term for a set of regulations for the design and installation of electrical wiring in a building. The intention of such regulations is to provide standards to ensure electrical wiring systems are safe for people and property, protecting them from electrical shock and fire hazards.
It is part of the National Fire Code series published by the National Fire Protection Association (NFPA), a private trade association. [1] Despite the use of the term "national," it is not a federal law. It is typically adopted by states and municipalities in an effort to standardize their enforcement of safe electrical practices. [2]
Electrical wiring practices developed in parallel in many countries in the late 19th and early 20th centuries. [7] As a result, national and regional variations developed and remain in effect. (see National Electrical Code, electrical wiring, electrical wiring in the United Kingdom). Some of these are retained for technical reasons, since the ...
NEMA 5-20R outlets, which are similar to type B but have a T-shaped neutral slot, are sometimes used for higher current 120 V equipment (up to 20 A). Homes are typically provided with 120/240 V split-phase power; NEMA 14-30R and 14-50R receptacles are provided on 240 V circuits for clothes dryers and electric stoves .
Three live (hot) wires and the neutral are connected to the building for a three phase service. Single-phase distribution, with one live wire and the neutral is used domestically where total loads are light. In Europe, electricity is normally distributed for industry and domestic use by the three-phase, four wire system.
The first rubber-insulated cables for US building wiring were introduced in 1922 with US patent 1458803, Burley, Harry & Rooney, Henry, "Insulated electric wire", issued 1923-06-12, assigned to Boston Insulated Wire and Cable . These were two or more solid copper electrical wires with rubber insulation, plus woven cotton cloth over each ...
In many countries the plug of a class 0 equipment is such that it cannot be inserted to grounded outlet like Schuko. The failure of such an equipment in a location where there are grounded equipment can cause fatal shock if one touches both. Any Class 1 equipment will act like a Class 0 equipment when connected to an ungrounded outlet.
The International Electrotechnical Commission publishes the 60079 series of standards [2] which defines a system for classification of locations, as well as categorizing and testing of equipment designed for use in hazardous locations, known as "Ex equipment". IEC 60079-10-1 covers classification of explosive gas atmospheres, and IEC 60079-10-2 ...