MSL1-63 series circuit breaker is used for protection again indirect touching of parts under voltage,for prevention of lasting voltage on earthed parts which appear because of a defect in the electrical installation and for protection against direct contacts of parts under voltage in case of I△≤ 30mA.Residual current circuit breakers can be used in TN-S,TN-C,TT and IT network systems or with other words in all system where neutral and pretective conductor are separated(VDE 0100 Teil 410)