JM1L series residual current operation circuit breaker (hereinafter referred to as circuit breaker) is mainly used in power distribution networks with AC 50Hz and rated current up to 800A. It is used to provide indirect contact protection for people, and it can also be used to prevent equipment insulation damage and ground faults. It can be used to distribute electric energy and protect the overload and short circuit of circuits and power equipment, and it can also be used for infrequent switching of lines and infrequent starting of motors.