Under normal circumstances, the protection transformer and distribution line can be equipped with a universal circuit breaker, and the motor can be selected as a plastic case circuit breaker. Check the wiring direction of the circuit breaker. If the circuit breaker technical file or terminal indicates that it can only be used for the incoming line, the lower incoming line should not be used for installation. The bus switch must use the circuit breaker with the lower incoming line.

It should be noted that in addition to the general selection principle, the use of the circuit breaker should also be considered. Circuit breakers for circuit breakers and motor protection, and circuit breakers for lighting and daily use shall be selected according to the characteristics of use. Not all circuit breakers require an undervoltage release, and it should be determined according to the requirements of use. In some systems with poor power supply quality, circuit breakers with undervoltage protection are used, which often cause undesired power outages due to voltage fluctuations. In this case, if an undervoltage release is necessary, an appropriate delay should be considered.

The DC miniature circuit breaker, also called DC open or DC micro disconnect, is a kind of DC circuit breaker and is the most common component in low voltage circuit breakers. It is mainly used in DC lines with rated voltage up to 250V~1000v and rated working current to 1~60A. It is used for overload, short circuit protection and infrequent conversion of DC lines. The circuit breaker can also be equipped with accessories such as auxiliary contacts, alarm contacts and shunt trips to achieve long-distance breaking and provide control signals.

 It can not only switch on and off the normal load current and overload current, but also switch on and off the short-circuit current. In addition to the control role in the circuit, it also has certain protection functions, such as overload, short circuit, under voltage and leakage protection. The low-voltage circuit breaker can be operated manually or electrically, or remotely.