... 690V,800V.. YKM1 series of molded case circuit breaker (short for circuit breaker), is the latest circuit breaker of advanced technology. The ... voltage is 800V, (YKM1-63: 500V), used for the circuit of rated working voltage 690V and below, (YKM1-63: 400V ... transfer and infrequently starting. The circuit breaker have the functions of overload, short circuit and undervoltage protection which can protect ...