You must have seen the device in diagram shown beside, which is connected just below the live wire carrying current from electricity meter to our house. This device plays very important role for saving our appliances from getting damaged due to excess current that can be pass through the wires. It is known electric fuse. The fuse is a safety device connected in series with live wire who carries the main current into the electric appliances used in house such as television, washing machine, refrigerator, microwave oven and many more.
Electric fuse acts as circuit breaker or first automatic switch when excess current passes through the live wire. Electric fuse works on the principle of heating effect of electric current.
Wire made up of an alloy of lead and tin has low melting point about 2000 C is used in fuse, which is joined between two terminals of ceramic box shown above. When current passes through this wire, it gets heated instantly. It can bear heat if current passes through it is limited. If excess current produced by any means (may be due to short circuiting, overloading or any accidental circumstance) passes through this fuse wire it gets heated immediately beyond permissible value and melts due to overheating. This disconnects the main circuit automatically and we can prevent our appliances from getting damaged. Due to this property electric fuse are also known as ADS (Automatic Disconnection of Supply).Today there are thousands of different fuse designs are available in a market which have specific current capacities and response times, depending on the application. Like other instruments, fuse also has one important drawback that it disconnects entire circuit of house so we face outage of electricity for a particular time. To get electricity back, we need to replace the burnt wire by another one.
Q. What is the principle of working of electric fuse?
Ans: It works principle of heating effect of electric current.
Q. Which material is used for making fuse?
Ans: An alloy of lead and tin.
Q. What is melting point of wire of fuse?
Ans:Around 2000 C.
Q. How electric fuse can save domestic appliances from getting damaged due to excess current?
Ans:When excess current produced by any means passes through the fuse wire it gets heated immediately beyond permissible value and melts due to overheating and disconnects the main circuit automatically.