Types: drop-out and load switching For outdoor use High voltage protective device To be connected with incoming feeder of distribution transformer or distribution lines It mainly protects transformer or lines from short circuit and overload, and on/off loading, current Drop-out fuse cutout is composed of insulate insulator supports and fuse tube Static contacts is fixed on two sides of insulator support and moving contact is installed on two ends of fuse tube Fuse tube is composed of inside arcexting tube, outer phenolic compound paper tube or epoxy glass tube Load switching fuse cutout provides enforced elastic auxiliary contacts and arc-extinguishing exclosure switching on-off loading current At normally working via fuse link tightened the fuse tube is fixed to form up of close position In case system fault occurs, fault current result, resulting in immediate melting of fuse and take piece electric are, which let arc-extinguishing tube being heated and explode, emitting a lot of gas. This will produce high pressure and below of the are along with tube After fuse link melt melt moving contact has no tightened strength again, mechanism is locked and fuse tube drop out, cutout now is in open position When it needs to switch off during cutout loading, operator shall via insulating operating bar pull the moving contact, at its beginning main contact and auxiliary static contactic contacted still. While pulling the auxiliary contact is separated between auxiliary contacts there occur electric arc and the arc will be lengthened in arc-extinguishing enclosure gap and meanwhile arc-exiting explode gas to blow off the arc during current passing zero