How to choose the circuit breaker for the battery cabinet

The highest voltage that may be applied over all end ports, the distribution type, and how the circuit breaker is completely integrated into the system all contribute to the overall voltage rating. It is essential to choose a circuit breaker with sufficient voltage capacity that corresponds to the end application.

Round the breakers up to next common size and you have600A vs 500A. If the battery cabinet design is only for capacity (meaning all cabinets must be on line to handle discharge) one could use 500A breaker, maybe even 450A in the scenario above. Sometimes it is requested that 600A be used however.

These can be equipped with a monitoring device connected to the UPS or BMS to warn if a fuse has tripped or is disconnecting the battery from the UPS. The DC rated Battery Circuit Breaker (BCB) provides still overcurrent protection, if correctly coordinated, even though it is not as fast as the fuses.

It is commonly acknowledged that the breaker control panel can handle a fault current no higher than the interrupting rating. Interrupting a circuit breaker does not automatically cause the system to fail. At any given moment, it is possible to compute the maximum fault current that a system can supply.

The allowable current carrying capacity of the line is not less than the setting value of the long-delay operating current of the circuit breaker. If wire and cable are used, the long-delay operating current setting value of the circuit breaker can be 80% of the allowable current carrying capacity of the wire and cable.

When installing a circuit breaker, there is one hard and fast rule: The breaker's interrupting capacity must be at least double the fault current that will be provided at the location of the breaker. If the amount of interrupting capacity is not applied correctly, the breaker could be damaged.