Nuisance Tripping Failure Modes and Corrective Actions in Molded Case Circuit Breaker

Molded Case circuit Breaker is a critical component in protection system which provides protection against overload and short circuit. It has been widely used particularly in North America region. Nuisance tripping is a common failure with low voltage circuit breaker. In previous papers, Nuisance tripping of Residual Current Device (RCD), Miniature Circuit Breaker (MCB), Arc fault Circuit Interrupter (AFCI) has been discussed by many authors. This paper focuses on Molded Case Circuit Breaker (MCCB) Nuisance tripping failure. Its symptoms, all possible causes and corrective and preventive actions has discussed to prevent unwanted operation which helps to minimize recurrence of failure to improve the quality performance for reliable operation.