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Circuit Breakers

Circuit Breakers
Circuit Breakers
A circuit breaker is an automatically-operated electrical switch designed to protect an electrical circuit from damage caused by excess current.

Its basic function is to interrupt current flow after a fault is detected, typically resulting from an overload or short circuit. Unlike a fuse, which operates once and then must be replaced, a circuit breaker can be reset to resume normal operation.

Classifications of circuit breakers can be made based on voltage class, construction type, interrupting type, and structural features. Circuit breakers also come in a variety of sizes: from small devices that protect low-current circuits or individual household appliances, up to large switchgear designed to protect high voltage circuits feeding heavy machinery.

Circuit Breakers: Learn About Circuit Breakers Here > Circuit Breakers are reusable overcurrent protection devices. After tripping to break the circuit, the breaker can be reset to protect the circuit again. There are two accepted definitions for circuit breakers. The National Electrical Manufacturers Association (NEMA) defines a circuit breaker as a device designed to open and close a circuit, by non-automatic means, and to open the circuit automatically on a predetermined overcurrent without injury to itself when properly applied within its rating. The American National Standards Institute (ANSI) states that a circuit breaker is a mechanical switching device capable of making, carrying and breaking currents under normal circuit conditions. Also, it is capable of making and carrying a current for a specified time, and breaking currents under specified abnormal circuit conditions such as those of a short circuit.