Advertisements
Advertisements
Question
Why is it necessary to have an earth wire installed in a power circuit, but not in a lighting circuit?
Solution
Power circuit carries high power and costly devices. If there is some unwanted power signal (noise) in the wire it can damage the device. To reduce this effect earth is necessary. Lighting circuit carries low power (current). So, we ignore the earth terminal.
APPEARS IN
RELATED QUESTIONS
To which wire of a cable in a power circuit should the metal case of geyser be connected.
An electric iron is rated 220V, 2kW.
1) if the iron is used for 2h daily find the cost of running it for one week if it costs 4.25 per kWh
2) Why is the fuse absolutely necessary in a power circuit?
What do you mean by the term local earthing? Explain how it is done.
The metal case of an electric appliance is earthed explain the reason.
- The earthing of an electric appliance is useful only if the fuse is in the live wire. Give the reason.
- Name the part of the appliance which is earthed.
For earthing an electrical appliance, one has to remove the paint from the metallic body of the appliance where the electrical contact is made. Explain the reason.
What is meant by earthing of an electrical appliance? Why is it essential?
In a three-pin plug top, one of the pins is thicker and longer than the other two, Give reason. Name this pin.
