In electrical system, an Earth pit refers to a pit, dug […]
In electrical system, an Earth pit refers to a pit, dug in earth with some standard filling. Primarily Earth pits are used for SAFETY towards SHORT CIRCUITS. It also acts as the reference point for different electric power sources. As Earth Pits are easy to make and maintain so since starting of commercialized Electricity, Earth pits are used as reference points.
How it saves human from electric shocks?
As we know that current chooses the lowest resistance path. And the resistance of human body is about 300 Ohms (depends on several factors) and that of Earth is very low. So the current will go into the earth through grounding wire.
If a machine or equipment is properly grounded into the earth, it has less chances to get damaged. In case of short circuit or any other accident, the current will rush to the lowest resistance path i.e. into the earth. And a OCR(over current relay) will sense the high current and will cut off the supply.