Miniature circuit breakers includes a broad range of devices defined as supplementary protectors. Supplementary protectors are typically used for control circuits, lighting, business equipment, appliances and a range of other applications where closer protection is desired than that offered by a branch circuit protection device. Current limiting design provides fast short-circuit interruption that reduces the let-through energy that can damage the circuit. Thermal-magnetic overcurrent protection. Trip-free design breaker can not be defeated by holding the handle in the ON position. Field-installable shunt trip auxiliary switch and under voltage release.