circuit breaker Circuit Breaker Sturdy Material: The flame retardant shell is made of nylon material PA66, not easy to deform and also has excellent durability. Circuit Breaker: Used to low voltage electrical systems from damage caused by over current, overload or short circuit. Reliable Works: Has 6000A rated ultimate short circuit breaking capacity, AC 400V rated voltage and 20A rated current as well. DIN Rail Mounts: With modular structure and bistable locking clip, the DIN rail mount on distribution box is very convenient.