1. Rated working voltage: should be greater than the DC circuit voltage.
2. Short-circuit breaking capacity: greater than the maximum short-circuit current through the DC circuit breaker.
3. The operation current and time between the upper and lower stages of the circuit breaker should be selective. After the rated current of the DC circuit breaker has been determined, its protection characteristics have also been determined, so the determined scheme should be as follows.
4. Dc bus contact electrical appliances should use DC disconnecting switch. But small capacity battery using single bus section wiring, the bus section electrical, DC circuit breaker can be selected, the protection selectivity depends on the engineering situation and different.