Fuse- it is the device that is used in electric circuits. it's internal structure is too much like a bridge joining two banks of a river. in a fuse there are two points wire from 1 point joins to mains wire from the electric pole and another is joined to internal wiring of house. between two points there Is a wire joining two points. this wire is same as the wire which is fitted in our houses.
it is mainly of copper.
working- this is to save the whole house appliances to get damaged due to high voltage. it works like this.,first the current has to pass through the fuse wire when there is high voltage the amount of heat produced burns the wire and wire breaks. so this prevents other appliances from damaging.