Abstract: This paper analyzed the problem that the shunt release of moulded case circuit break(MCCB) does not operate at low temperature.The solution to the problem of low temperature non-action of auxiliary suction shunt release and self suction shunt release was proposed respectively.The analysis shows that the problem is related to the way of applying lubricating grease,as well as the rolling and polishing process.

Key words: moulded case circuit break(MCCB), shunt release, low temperature, lubricating grease, rolling and polishing process