Discuss the main feature of a domestic wiring system with the help of a schematic diagram of one of the common domestic circuits .

Explanation

(1) In our homes , we receive supply of electric power through a main supply (also called mains), either supported through overhead electric poles or by underground cables .
(2) This supply is through the live / positive wire (red insulation cover ) , neutral / negative wire (black insulation cover) and the earth wire (green insulatio cover).
(3) The potential difference between the live wire and neutral wire is 220 V and the frequency of AC is 50Hz.
(4) At the meter -board in the house , these three wires pass into an electricity meter through a main fuse .
(5) Through the main switch they are connected to the line wires in the house .
(6) These wires supply electricity to separate circuits within the house .
(7) Often , two separate circuits are used , one of current rating 15A for applicances with higher powe ratings such as geysers, air coolers , etc and the other of current rating 5A for bulbs , fans ,radio etc.
(8) The earth wire is usually connected to a metal plate deep in the earth near the house as local earthing .
(9) Inside the house , in each separate circuit, different appliances are connected across the live and neutral wire. Each appliance has a separate .ON./.OFF. switch to complete the circuit or to discontinue te current in the circuit .
(10) In order that , each appliance has equal potential difference , all appliances are connected in parallel across the supply.
[Note : See Chapter 12 for advantages of a parallel connection].