... ,2P,3P,4P Glade D type surge protective device 1. Description:Surge protection device (SPD, surge protector, surge arrester) is suitable for TT, ... GB18802. It adopts 35mm standard rail. When SPD fails in breakdown for over-heat and over ... -current, the failure release will help electric device separate from the power system and give indication ... provided. Grade D protected power surge protective device