Residual current operated circuit breaker siemens earth leakage circuit breaker with integral over current protection can be used in the domestic and public field for otimu protection of life against the risks if in direct contacts and electrical installations against short- circuits or overload. The residual current operated circuit breakers with integral over current. Protection combines in fact a protection against ear thing faults (differential protection) and a protection against over currents detected in the installations magnetothermic protection versions suing a rated residual fault current of 30mA also assure an additional protection in case of direct contacts. KM series are equipped with over current triggers integrated and manufactured according to the most recent national and international regulations: standards IEC1009-1 and IEC2318, their sizes are in compliance with the regulations of the standard DIN43880, one module is 18mm (1pole), front window height equal to 45mm. According to IEC1009-1, FSM type of RCBO has no special operating process, so it can be sued by laypeople.