Air Circuit Breakers are suitable for AC 50Hz, rated voltage up to 660V (690V) and below, rated current 400A-6300A in the power distribution network, used to distribute power and protect the lines and power supply equipments from the hazards of overloading, undervoltage, short-circuiting, single-phase grounding and other faults. The circuit breaker has intelligent protection function and precise selective protection, which can improve the reliability of power supply and avoid unnecessary power outage. Meanwhile with open communication interface, it can be four remote to meet the requirements of centralized control center and automation system. The circuit breaker has an impulse withstand voltage of 8000V at an altitude of 2000 meters (different altitudes are corrected according to the standard, up to 12000V). The circuit breaker can be used as an isolator without intelligent disconnectors and sensors. Optional ACB supporting RS485/RS232 communication.