The type of "3+1" surge protection device (surge protector, surge arrester, lightning arrester, SPD, TVSS) effectively avoid the transient current and over-voltage in the 3-phase power system, which is suitable for TT, TN sustem. It is high-energy protector which is used between the N-line and PE-LINE. Its large power handling and fast response time will protect your sensitive equipment against the wrost lighting surge.