Drop-out fuse [RW11-12 / 200A, RW3-12 / 200A] consist of insulating support, the composition of static and dynamic contact, fuse tube of three parts. Static contact mounted on the insulating support both ends of the fuse tube from the inner tube and the outer arc of phenolic paper tube or epoxy glass fiber cloth tube. Drop-out fuse is 10kV distribution line and distribution transformer branch lines most commonly used as a short-circuit protection switch, it has an economic, easy to operate, adapt to the outdoor environment and other characteristics, it is widely used in 10kV distribution lines and distribution transformer primary side as a protective device and be cast, cut operating purposes. Drop-out fuse [RW11-12 / 200A, RW3-12 / 200A series fuse] work process in the power circuit, in normal operation, the fuse with a button mounted on the contact fuse tube, is fitted tabletting pressure relief cap pressed fuse fuse tube is pulled out by the end of the line, it will pop back pressure near the nozzle plate twist connection with the lower contact, under the action of the pop-up plate torsion fuse has been a state of tension, and locking joint activities. When the fuse is in the closing position, the static contact shrapnel down and outward thrust, making contact with the entire fuse more reliable. Drop-out fuse [RW11-12 / 200A, RW3-12 / 200A] Profile drop fuse 10kV distribution lines installed in the branch line, can reduce the power range, because there is a high drop-out fuse apparent disconnect point, with the isolation switch function to repair lines and equipment segment to create a safe working environment, increased maintenance personnel security. Mounted on the distribution transformer, distribution transformer can be used as the main protection, so, in the 10kV distribution lines and distribution transformers has been popular. Drop-out fuse [RW11-12 / 200A, RW3-12 / 200A] operating under normal circumstances do not allow note-load operation of drop-out fuse, only allowing it to operate load devices (lines). But in the rural power network 10kV distribution lines branch lines and the rated capacity of less than 200kVA distribution transformer allows operation with a load according to the following requirements: (1) operations carried out by two persons (one care, one person operation), but must be worn by passing the test insulated gloves, wear insulated boots, wearing goggles, use a voltage rating that matches qualified insulation rod operation, disable operating at lightning or heavy rain climate. (2) When wind up operations, the general provisions of the first to pull off the intermediate phase, and then pull the leeward side of the phase, the final phase pull off the windward side. This is because the three-phase distribution transformers run into two-phase operation, pull off the arc sparks generated intermediate phase minimum, without causing phase short circuit. Second is to pull off the leeward side of the phase, because intermediate phase has been opened, the leeward side of the phase to phase windward edge distance doubling, even with over-voltage generated, resulting in the possibility of short circuits is small. Finally, with time to pull off the windward side, only to ground capacitance current, already very slight spark generated. (3) when closing sequence wind up the operation contrary, the first phase close windward side, and then close the leeward side of the phase, and finally close the intermediate phase. (4) Operating melting tube is a frequent project, not notice contact will result in burns cause poor contact, the contacts overheating, spring annealing, prompting more bad contacts the contact, creating a vicious cycle. So, pull, when combined melting tube to force moderate, after Hao, to double-check the duckbill tongue can closely link more than two-thirds the length of the tongue, can wind up hooked on the lever few downward pressure duckbill, then gently pull test to check for Hao. Closing time failed to put in place or close securely, insufficient contact pressure on the fuse quiet, can easily cause contact burns or fuse tube drop on their own.