RY1 Surge Protective Device In three-phase four lines system, three-phase lines and one zero line are connect protector for the earth cable.In normal situation, the surge voltage protector is high resistance. When the power system or other reason appear the surge over voltage, the protector will rapidly transmit, then it will lead the voltage into earth and protect the electrical equipment, as the surge voltage through the protector and after disappear the surge voltage protector recover to high resistance and it will not influence the normal run. Single phase 220V electrical tenet.Surge voltage protector tenet Features A)Mould--no cut off current it can replace protector unit. B)Large current--the maximum current 40KA(8/20us) C)High rapid--operating responses time less 25ns D)Display form--windows colors indicating the Protector working state, Green(normal) Red (trouble). E)Appendant function: I. Acoustic optic alarm II. Trouble tele-control contact III. Thunder counter IV. Waterproof case