NF-SS moulded case circuit breaker(MCCB), it's applicable circuit of AC 50Hz(or 60Hz), ratedinsulation voltage 690V(AM3-125 500V), rated operating voltage AC 690V or below, rated oper-ating current 12.5-1600A, for distribute energy of electric and infrequent making and breakingcircuit in normal condition. The circuit-breakers are provided with the function of the protectionagainst overload and short circuit and under-voltage. The circuit breakers comply with standardof IEC60947-2. The circuit-breakers are double insulating (Inm=250A or above), the controlcircuit of the accessories is set apart with the main circuit, and doesn't need to open the coverof the circuit-breaker when install the accessories.