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 The alternating voltage generated is first stepped up from 11 kV to 132 kV at the
generating station or the grid sub-station

 At the main substation, the voltage is stepped down from 132 kV to 33 kV
 At the intermediate sub-stsubstationvoltage is stepped down from 33 kV to 11 kV

 At the city sub-station, it is stepped down from 11 kV to 220 V to supply to the
domestic consumers

Power distribution in a house

Electric power distribution is the final stage in the delivery of electric power; it carries
electricity from the transmission system to individual consumers. Distribution

substations connect to the transmission system and lower the transmission voltage to
medium voltage with the use of transformers.

Cables or wires are used to supply power to a house from the city sub-station-Live (or
phase) wire (L), Neutral wire (N), Earth wire (E)

A fuse is connected in the live wire at the pole or just before the meter, and is called the

company fuse. After the company fuse, the cable is connected to a kWh meter.

Connections are then made to the distribution board through the main fuse and the

main switch; it is a double pole switch.

Domestic Electric Circuits

o We receive power in our house through a main supply, commonly called mains.
o It is supplied through overhead cables or underground cables.
o There are 3 types of wires in domestic circuits : Earth Wire, Live Wire, Neutral Wire.
o Earth wire: It is generally green in color. It is usually connected to a metal plate
placed in the earth near the house as a safety measure to ground gadgets that
have a metallic body. (refrigerator, toaster). In case of charges leaking on to the
metallic body, the charges gets grounded and thus prevent shocks.
o Live wire: Positive wire generally red in color
o Neutral wire: Negative wire generally black in color
o The potential difference (or voltage) supplied in our country is 220V