The MCCB (Plastic-enclosed Circuit Breaker) mainly consists of an insulating housing, incoming and outgoing line terminals, operating handles, nameplates, indicator Windows, fixed installation holes, conductive contact systems, tripping mechanisms, internal transmission mechanisms and upper cover protection plates, etc.

Among them, the insulating housing serves to insulate and protect, safeguarding the internal components. The incoming and outgoing line terminals are used to connect power lines and load lines. The operating handle is used to manually control the closing and opening of the circuit breaker. The nameplate indicates important parameters such as rated current, voltage and breaking capacity. The conductive contact system is responsible for the connection and disconnection of the main circuit and is the main part through which current passes. The tripping mechanism is an important protective component of MCCB. When an overload or short circuit occurs in the line, it can drive the circuit breaker to trip automatically and cut off the fault current. The internal transmission mechanism is responsible for connecting the operating handle with the contact mechanism to achieve mechanical linkage. In addition, the fixed installation holes facilitate the installation of the circuit breaker inside the distribution box or control cabinet, while the upper cover protection plate provides protection for the internal structure and makes later maintenance easier.