Generally, the current of thermomagnetic release of most domestic moulded case circuit breakers is not adjustable. Some manufacturers can adjust the current of thermomagnetic release (such as Schneider's TMD release type). This kind of thermomagnetic switch belongs to mechanical adjustment, and its general accuracy is not very good. It belongs to rough adjustment. If it is adjustable, it can be used. Select electronic intelligent plastic shell switch. The adjustable current can not exceed the shell current. The tripping characteristic of the moulded case circuit breaker is 1.05In without action. In the case of hot state, 1.3In operates within two hours. The setting current we mentioned is generally rated current, and the long delay action value is estimated to be about 1.3In.