Low voltage circuit breakers, commonly known as automatic switches or air switches, are used for infrequent on-off control in low-voltage distribution circuits. It is a control and protection electrical device that can automatically disconnect the faulty circuit in case of short circuit, overload or undervoltage faults.

There are many types of circuit breakers, which can be divided into DW frame circuit breakers, DZ plastic shell circuit breakers, DS DC fast circuit breakers, and DWX and DWZ current limiting circuit breakers according to their uses and structural characteristics. Frame type circuit breakers are mainly used as protective switches for distribution lines, while plastic shell circuit breakers can be used not only as protective switches for distribution lines, but also as control switches for motors, lighting circuits, and electric heating circuits.