A
circuit breaker is an automatically operated
electrical switch designed to protect an
electrical circuit from damage caused by
Overcurrent/overload or
short circuit. Its basic function is to interrupt current flow after
Protective relays detect
faults condition. 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 an individual household appliance up to large
switchgear designed to protect
high voltage circuits feeding an entire city.