What is the function and working principle of plastic case circuit breakerCircuit breaker is also called device circuit breaker. It is suitable for protection switch of branch circuit. It can automatically cut off the current when the current exceeds the jump-off setting. It is used to isolate all parts of conductor and grounding metal part, which are sealed in plastic shell. Auxiliary contacts, undervoltage trippers and divider trippers are modularized. Because the structure is very compact, the plastic case circuit breaker can not be repaired basically, so it is generally not considered maintenance.