Patent attributes
A circuit breaker has a molded case with a main case, a middle cover and a top cover being dividable from one another. The main case contains contactor sections, each including a stationary contactor and a movable contactor for a pole corresponding to each phase in a polyphase circuit, an arc-extinguishing device, an overcurrent tripping device actuating a tripping mechanism by detecting an overcurrent, and a zero-phase current transformer detecting a leak current. The middle cover has a partitioned recess for containing a switching mechanism and the tripping mechanism. Interpole partitions, surrounding the contactor section and the arc-extinguishing device, and a screen-like intermediate partition, isolating the contactor sections from the overcurrent tripping device, are formed with the middle cover laid on the main case. A wall with gas outlets for an arc gas is provided on the back of the arc-extinguishing devices.
