Circuit breaker once said that the automatic switch, refers to connect, bear and breaking under the condition of normal circuit currents, can also be connected under the provisions of the non normal circuit conditions, bear and breaking current (of a mechanical switching device. According to the provisions of the conditions, the distribution circuit, motor and other electric equipment to implement breaking operation and exert a protective effect when the circuit is overload, short circuit or less voltage can automatically disconnect switch of electrical circuits.

Generally speaking, the circuit breaker is a protection switch can be automatically cut off the fault line . It can not only be used to switch on and off normal load current, current and overload current, used to connect and breaking short-circuit current, under normal circumstances can also for less frequent to connect and disconnect the circuit and control the motor start and stop.

Breaker has the action value can be adjusted, with overload and protection of the two functions, easy to install, breaking capacity, especially in the fault current after the fault is generally not need to replace parts, so the application of a very wide range.