... surge protection device (in short: SPD, alias: surge suppressor, surge arrester) is suitable for TN-S, TN-C-S, TT, IT ... surge protective device is applicable for D,C,B grade lightening-proof, installed on the joint of LPZOA zone or LPZOB ... , which protects the electric network not shocked by thunder and lightening. These series usually installed in household distribution boards, computer equipment ...