... type surge protective device Amp:20-40KA, 10-20KA Pole:1P,2P,3P,4P Low voltage power surge protective device 1. Description: surge protection device (SPD, surge protector, surge arrester ... -heat and over-current, the failure release will help electric device separate from the power system and give indication signal. White ... .6. Best service after sale are provided. AC OBO type surge protective device