Electric System Glossary

• circuit - The path electric current takes from the power source to the device using the power and back to the source.

• circuit breaker - A protective device that opens an electric circuit when a short occurs or the system is otherwise abnormally stressed. WEMC's circuit breakers are configured to reset automatically. This keeps long term outages from happening when temporary problems occur, like tree branches touching a line.

• distribution system - The poles, wire and transformers used to deliver electric energy from a bulk power supplier to the consumer. The distribution system begins at the substation and ends at the service entrance of the home or business.

• fuse - A metal device that protects electrical equipment by melting and opening the circuit when a short circuit, other fault or overload occurs.

• hot wire - The ungrounded current carrying wire in an electrical system.

• house knob - An insulated support on the side of the roof that provides a place for the electric company to attach incoming electric lines.

• insulator - A device that supports electric wires and prevents undesired flow of electricity; usually made of glass or porcelain.

• journeyman line technician - An electrical lineworker who has completed apprenticeship training and has learned the trade.

• line, power line - A carrier of electricity on an electric power system.

• main circuit - A power line that serves as the backbone of the electric system. Main circuits leave the substations and branch out to taps and service wires. Another good description of main circuit is trunk line.

• meter - A device used to measure and record the amount of electricity used by a consumer.

• meter base - A metal enclosure that houses an electric meter.

• neutral wire - A grounded current carrying wire in an electrical system.

• outage - Interruption of service to an electric consumer because a power plant, transmission line, distribution line or other facility is not operating.

• recloser - A device that isolates sections of electric lines to help prevent long-term outages and system damage.

• service mast - A vertical pipe that extends above the roof line to accommodate entering electric service wires.

• service, service drop - The line that carries electricity from a distribution line to a home or business.

• single phase line - An electric distribution line that consists of one "hot" line and one neutral line.

• substation - An electrical facility containing equipment for controlling the flow of electricity from supplier to distributor.

• tap - An electric circuit with limited capacity extending from a main circuit; usually supplies a small amount of consumers (small may mean an entire subdivision) of consumers.

• three-phase line - An electric distribution line that consists of three "hot" lines and one neutral line. Used in heavily populated areas or to supply large commercial loads.

• transformer - A device used to lower or raise voltage. A distribution transformer lowers line voltage from 14,400 to 240 volts before the electricity enters a home or business.

• transmission line - The poles, towers and lines used to move bulk electricity from a generating plant to a substation.

• voltage - measurement of electrical pressure.

• weather head - An enclosure that allows wires coming into a building to pass through while keeping out water.