Miniature circuit breaker, MCB, is mainly composed of operating device, tripping device, contact system and arc control system. It is widely used in terminal circuits of household and installation for the distribution, control and protection of circuits and electrical equipment. Firstly, the paper introduces the status and development trend of MCB product and its reliability study. Secondly, it ... [Show full abstract] overviews the method, plan and procedure of reliability test for MCB. Finally,it provides a actual case of reliability test for MCB. The case proves that reliability test is of great importance in maintaining and improving product reliability.