Four-pole miniature circuit breakers protect four circuits from current overloads at the same time. They're UL489 listed for use as branch circuit protection or as supplementary protection from damage caused by short circuits. These circuit breakers follow trip curves to determine when they will interrupt the current. If the current exceeds a device's rating up to a certain factor, the circuit breaker will have a delayed trip to prevent nuisance tripping. If the current exceeds the device's rating at or above that factor, it will immediately trip. They're mounted on standard 35mm DIN rail in low-voltage electrical applications such as control panels, motor control centers, and panelboards.