ICSE Class 10 Answered
The electric power line enters our house through three wires- namely the live wire, the neutral wire and the earth wire.
To avoid confusion we follow a colour code for insulating these wires.
The red wire is the live wire, and the black wire is neutral.
The earth wire is given green plastic insulation.
The live wire has a high potential of 220 volts whereas the neutral wire has zero potential.
Thus the potential difference between the live wire and the neutral wire is 220-0 = 220 volts.
The earth wire is much thicker in size and is made of copper.
One end of it is connected to a copper plate buried deep under the earth.
The earth connection is made to the electric meter and then to the main switch.
The live wire and neutral wire, coming from the electric pole, enter a box fitted just outside our house which has a main fuse F1.
The fuse is connected in series with the live wire.
This is done so because it is only the live wire which has a high potential of 220 volts unlike the neutral wire which carries zero potential.
The fuse F1 has a high rating of about 50 amperes.
Thus it prevents any damage such as fire to the entire electrical wiring entering the house due to short-circuit or overloading.