Surge Protective Device(Surge protector,Arrestor) It protects the electric network shocked by the thunder or over voltage . Surge Protective Device(Surge protector,Arrestor)Usage and application scopeUsage and application scope of BY10 type surge protective device (short name "SPD") is suitable for AC 50/60 Hz,380V and the following electric power systems,such as TT, IT, TN-S, TN-C, TN-C-S. It ...