Federal miniature circuit breakers protect the electrical circuit. They are connected to against over current and short circuits. They allow easy open-close of the circuit. Miniature circuit breakers are manufactured with 1, 2, 3 and 4 poles from 6A to 63A in accordance CE. There are two separate types as B and C. In case of a short circuit, B types open the circuit at 3 or 5 times more then nominal current and C types open the circuit at 5 or 10 times more than the nominal current. Miniature circuit breakers with 2, 3, 4 poles disable the device they are connected to, thanks to their mechanisms in case of a failure in any phase. B type : Used in illumination of houses, plugs and control circuits. C type : Used in inductive loads like transformer, several fluorescent lamps etc. The device opening the current is enabled by lifting the lever in case of any failure. Lever-free opening mechanism shall open the current again as the failure continues. Federal miniature circuit breakers open the circuit in a very short time in case of a short circuit. In this way, thermal and magnetic forced of the short circuit current are limited. It provides ease in assembly thanks to small dimensions and capability of mounting on rails. Thanks to the design of connection terminals, accidentally touches are eliminated. Federal miniature circuit breakers resist an impact voltage of 6 kV, operate continuously under an ambient temperature of 55°C and resist a relative humidity of 95%. 25 mm2 cable can be connected to specially-designed cable inputs.