... series surge protection device (in short: SPD, alias: surge suppressor, surge arrester) is suitable for TN-S, TN-C-S, TT, IT etc. power supply system ... is a failure release mounted on the module of surge protection device. \When the SPD fails in breakdown for over-heat ... Scope and Installation PositionNS1-(D, C, B)5 surge protective device is applicable for D,C,B grade lightening-proof, installed ...