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Draw a schematic diagram of household/domestic wiring . Give its essential features. |
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Answer» Solution :Figure : Schematic diagram of domestic electric circuit Its main FEATURES are : Electricity is supplied to our homes either from overhead electric poles or underground wiresthrough mains using two wires. One is the live wire with red insulation cover and theother is NEUTRAL wire with back insulation. The POTENTIAL differencebetween the two is 220 volts in INDIA . At the meterboard of the house, these two wires pass into electric meter throughamain fuse. The fuse is a safety device which cutsof electricityif a high current flows through it. Through themain switch, the live and neutral wires are connected to line wires of the house which supply electricityof different circuits. The live wire of each circuitis connected to a separatefuse so that if excess current flows, only the electricityin that part of the circuitis cut off and othersare notaffected. In any part of the house, all appliancesare connected in parallel to each other across the live and neutral wires. This ensures full voltage across eachappliancefrom the mains. Each appliance is provided witha separate switch in its live wire for its operation. Generally thesecircuits are divided into heatingcircuits- which require15 A current and draw more power (likeair conditioners,geysers, etc.) and lightingcircuits - whichrequire 5 A current and draw lesserpower (like bulbs,fans, etc.) Anadditional earth wire with green insulation cover is connected to devices with metal bodies such as toaster, heater,etc. asa safety measure. Oneend of the earth wire is connected to metal part of the device and the other endis connected to a metal plate burieddeep in the ground. Any leakage current in the appliance will then be sentto the earth through earth wire. The burnt-out fuse should be replaced by another fuse of identical rating because ifa fuse of less ratingis used then is blowsoff whennormal current is flowing through it andelectric appliances shall not WORK. If the fuse of higherratingis usedin case of short circuitor overloading,the fuse wouldnot blow up and excess amount of current may harm the appliances. 
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