The thermal circuit breaker can be switched back on again, has a compact design and is available in nine finely graded steps for nominal currents from 0.25 A to 10 A. The integrated ON/OFF switching function makes it possible to switch the circuit breaker back on immediately after triggering thus increasing the availability of the system. The thermal circuit breaker TCP can be plugged into UK 6-FSI/C fuse base terminal blocks with screw connection technology and into ST 4-FSI/C terminals with springcage connection technology. For both types of terminal blocks, the potential distribution can be conveniently implemented using bridges.