Abstract: Low-voltage circuit breaker is significant in low-voltage distribution system. Various low-voltage circuit breakers are briefly compared in this paper. The parameters and characteristics of MCCB for motor protection and the differences between its over-current release and the over-current release for distribution protection are analyzed. The selection and setting methods for low-voltage circuit breaker for motor protection and its over-current release are summarized, and the steps of selection are discussed with examples.

Key words: low-voltage circuit breaker, motor protection, over-current release