TCP Thermal Device Circuit Breakers Phoenix Contact TCP Thermal Device Circuit Breakers provide optimum protection against overload for power distribution systems. When the circuit breaker trips, the integrated switch function enables immediate reactivation. Unlike a fuse, the circuit breaker does not need to be replaced. The higher the overload, the faster the thermal device circuit breaker trips. Phoenix Contact TCP Thermal Circuit Breakers include 5A, 12A, 16A, and 20A plugs in a slim package for protecting devices with higher nominal currents.