Circuit breakers are electromechanical devices that perform essentially the same function as a fuse. They are intended to make and break circuits under normal conditions and to break a circuit under an overload situation such as a short circuit. If there is a short circuit then the circuit breaker will trip (switch off the circuit), protecting the circuit.
The main difference between fuses and circuit breakers is that a fuse needs to be replaced whereas the circuit breaker can be reset (the circuit switched back on). Modern electricity supplies use circuit breakers instead of fuses at several locations within a building. If a circuit breaker trips then the circuit should be checked for faults before it is reset. Circuit breakers can also be used to switch off a circuit manually to make it safe for repair and maintenance.
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