Drop-out fuse cutout and load switching fuse cutouts are outdoor high voltage protection devices. They are connected with the incoming feeder of the distribution transformer or distribution lines. These are primarily used to protect transformers or lines from short circuits and overloads and switching currents. The drop-out fuse unit is composed of insulator supports and a fuse tube, static contacts are fixed on two sides of the insulator support and moving contact is installed on two ends of fuse tube. The interior of the fuse tube is the extinguishing tube. the exterior is made of the phenolic compound paper tube or epoxy glass. Load switching cutout fuse provides stretch auxiliary contacts and arc-extinguish closure for switching on/off loading current. In normal operation, the fuse link is tightened to form tho closed position. In the fault current situation, the fuse link melts and an electrical arc is formed. The arc-extinguishing tube is as occurs. This causes high pressure inside the tube and causes the tube to separate from the contacts. The strength of the contact is relaxed once the fuse elements melt. The cutouts now in the open position, the operator needs to switch the current off. Then with an insulated operating bar, the moving contact can be pulled off. The main contact and auxiliary contact is connected. Melt tube structure: Fuse take made of flberglsaa, damp-proof & corrosion-proof. Fuse base: Product base embedded mechanical structure and insulator. Install metal rod mechanism using special binder materials and insulator together , can with stand short-circuit current open the electric power. Moistureproof fuse has not blister, deformation, open ,large capacity, UV,long life, superior electric properties, dielectric strength and excellent mechanical stiffness and consecrated ability. The whole organization to neutral, convenient installation, safe and reliable. 1. The ambient temperature is not higher than +40 C, not lower than-40 C 2. The altitude does not exceed 3000m 3.The maximum wind speed does not exceed 35m/s 4. The earthquake intensity does not exceed 8 degrees1. When working normally, fuse link tightened the fuse tube to be close position. 2. If system occur faults, big fault current melts fuse immediately and take place electric arc, which makesarc extinguishing tube being heated and explode a lot of gases. This will produce high pressure and blow off the arc along with tube. 3. After fuselink melt moving contact has no tightened strength, mechanism is locked and fuse tubedropout. 4. Cutout now is in open position. Operator shall use insulating Link Rod to pull the moving contact.