circuit breaker

In by Jackie Dunn

A protective device that automatically opens an electrical circuit when it is overloaded.

Merriam-Webster Online Dictionary
circuit breaker (noun)
a switch that automatically interrupts the current of an overloaded electric circuit
circuit breaker (Wikipedia)
Circuit Breaker
Electronic symbol
An air circuit breaker for low-voltage (less than 1,000 volt) power distribution switchgear
A two-pole miniature circuit breaker
Four one-pole miniature circuit breakers
Molded-case or miniature circuit breaker

A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by excess current from an overload or short circuit. Its basic function is to interrupt current flow after a fault is detected. Unlike a fuse, which operates once and then must be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation.

Circuit breakers are made in varying sizes, from small devices that protect low-current circuits or individual household appliance, up to large switchgear designed to protect high voltage circuits feeding an entire city. The generic function of a circuit breaker, RCD or a fuse, as an automatic means of removing power from a faulty system is often abbreviated as OCPD (Over Current Protection Device).

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