Electrical Equipment of Buildings

the aggregate of the electrical engineering equipment that is installed in buildings and is intended to supply electric power to water-supply, ventilation, air-conditioning, lighting, and other systems, as well as to supply electricity to household electric appliances. The electrical equipment of a building includes the building’s electric-supply equipment, electrical installations for engineering facilities, and lighting installations.

Within a building, electric power is supplied through the building’s wiring system by means of service equipment and distribution centers. A building’s electric-supply equipment includes devices and equipment for the protection, control, switching, and metering of electricity. The service equipment and distribution centers are located at the point where the power lines, which carry a voltage of mainly 380/220 volts in the USSR, enter the building. The service equipment usually includes three-pole knife switches and protective devices. The distribution centers contain metering equipment and protective devices for the feeders or branch circuits that originate from them. Vertical sections of cable, or risers, are used to conduct electricity to users by floors and apartments through branch circuits.

Residential buildings usually have three branch circuits. The first is used for general lighting. The second supplies electricity to sockets that provide a current of 6 amperes (A); such sockets are used to connect household appliances with a rating of up to 1.3 kilowatts (kW). The third supplies electricity to 10-A or 25-A grounded sockets, which are used to connect appliances with a rating of up to 4 kW. Hot plates are connected to the third branch circuit by means of an additional plug-and-socket connection.

To supply electricity to lighting installations and to electrical installations for engineering facilities, separate risers are installed. Such risers have circuit breakers or fuses at the point where they originate.