Physics
What do you mean by the term local earthing? Explain how it is done.
Household Circuits
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Answer
Local earthing is done in the house near the kWh meter.
For this purpose, a hole nearly 2–3 metre deep is dug in the ground. A copper rod (or a thick copper wire) covered by a hollow insulating pipe, is inserted in the hole. A thick copper plate of dimensions 50 cm × 50 cm is welded at the lower end of the copper rod and it is buried inside the ground.
The plate is surrounded by a mixture of charcoal and salt to make a good contact between the plate and the earth. To keep the ground damp, water is poured through the pipe from time to time. This forms a conducting layer between the plate and the ground. The upper end of the copper rod is joined to the earth connection at the kWh meter.
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