The circuit breaker is composed of three-phase support type and mechanism chamber, which is simple in structure.@#Current transformer is installed on mobile terminal outgoing line and secondary interface adopts aviation socket, making it convenient to maintain and replace.@#Vacuum arc extinguishing chamber of the circuit breaker adopts technology of solid insulation, which is small in volume, long in service life and high in reliability. Its shield is exposed. It is sealed in epoxy resin, which is convenient for transportation.@#Operation mechanism is novel, simple, and reliable in operation and small in volume whose mechanical life can reach 10,000 times.@#Switch enclosure adopts stainless steel processed in spraying plastics, which is of sound corrosion resistance.@#It is allowed to be equipped with insulation switch, making a visible break and with reliable interlocking.@#It is able to be equipped with distribution terminal, realizing functions of four-remote and feeder automation.@#