General Fuse Cutout is a kind of outdoor high voltage of the distribution transformer or distribution lines and primarily used to protect transformers or lines against the impact raised by short circuit , overload and switching current . The drop - out fuse cutout is composed of insulator support and a fuse carrier , static contacts that are fixed on two sides of insulator support and moving contact installed on two ends of fuse carrier . The interior of the fuse carrier is the extinguishing tube while the exterior is made of phenolic compound paper tube or epoxy glass . During normal operation , the fuse link is tightened to form the closing position . In fault current situation , the fuse link melts and an electrical arc is formed . The arc - extinguishing tube is heated and explosion of gas occurs which causes high pressure inside the fuse carrier tube and makes the tube to separate from the contacts . The contact is relaxed once the fuse element melts . The fuse cutout is now in the open position , the operator needs to switch the current off . The moving contact can be pulled off by an insulated hot sticker . The main contact and auxiliary contact are connected . Structure Conditions of Application Ambient environment: 1.Temperature:-40℃≤T≤-40℃ 2.Altitude above sea level:≤1000m 3.Max.wind speed:≤35m/s 4.Earthquake intensity:≤8 degree