ZY2-C/3N surge protective device(call "SPD" as follows)applicable for TN-S, TN-C,TN-C-S, TT, IT etc power supply system with the rating of 50/60HZ, 380VAC or below, It is used for isopotential connection in interface between LPZOB and LPZ1 area in order to protect electric network from lightning or overvoltage operation. The products conform with GB 18802.1 and IEC 61643-1 standards.