WSBIL-100 residual current action circuit breaker(without over current protection suits for AC50/60Hz, rated voltage two poles 230V, four poles 400V, rated current up to 100A. When people contact or electrical net leak surpass the fixed value, the residual current action circuit break can switch off in short time to protect the security of man and electrical equipment, and can also be used for an infrequently switchover and infrequently starting of the motor.