F390 series (Alternating current and pulsating direct current & time- delay:S type)of residual current circuit breakers are mainly used in the electric distribution systemAC 230/415 V or less with rated current from 16A to 80A, for residential and industrial buildings, providing protection against electric surge. The normal RCCB can't contact with electric surge protecting device, however 390 series(S type)of RCCB can work together with normal RCCB to come into being a double protection: if the normal RCCB doesn't act, the 390 series (S type) of RCCB will act properly. It can be used in cable inlet as protection appliance. Five Circle Company is the one and only manufacture of F390 series (Alternating current and pulsating direct current & time-delay type) of Residual Current Circuit Breakers in China. F390 series of RCCBs are in accordance with IEC61008 and DIN VDE0664.