Question

What is the function of an earth wire

Answer 1

The earth wire, which has insulation of green colour,  is usually connected to a metal plate deep in the earth near the house. This is used as a safety measure, especially for those appliances that have a metallic body like electric press, toaster, table fan, refrigerator, etc. The metallic body is connected to the earth wire, which provides a low resistance conducting path for their current. Thus it ensures that any leakage of current to the metallic body of the appliance keeps its potential to that of the earth, i. e., 0, and the user may not get a severe electric shock.