Learn about the different types of molded case circuit breaker ( MCCB ) used for low tension (LT) distribution and feeder panels. Find out the supply, pole, breaking capacity, operation, utilization and protection release types of MCCB . This article covers molded case circuit breaker (MCCB) working /operating principle, its different parts and their functions, and labeled circuit diagram. Learn about MCCB (Molded Case Circuit Breaker), an automatic electrical device that protects low voltage circuits from overloading and short circuits. Find out the parts, functions, working principle, types, testing and maintenance of MCCBs. MCCB and MCB are both circuit breakers that protect electrical circuits from overload and short circuit. Learn the key differences, functions and applications of MCCB and MCB in this blog post.