Question

What is the value of earth resistance?

Answer 1

Hint: The current flowing to the grounds bases on the resistivity of the soil where the earth electrode exists. The soil has a resistivity that may vary from \[1{\text{ }}to{\text{ }}1000{\text{ }}ohm\] depending on the nature of the soil. The earth's resistivity depends on its temperature.

Complete step-by-step solution:
Earth is also a conductor and like any other conducting material, it has its conductivity (or resistivity). However, the earth’s resistivity varies at each point depending upon temperature, moisture level, presence of rocks beneath, etc.
Therefore if we drive a conductor into the soil and measure the earth’s resistance as per recommended practice, it will vary from point to point.
 The earth resistance can be reduced by increasing the size of the earthing electrode, mixing charcoal and salt with the soil, keeping the soil moist.
The earth has few ohms of resistance. This is necessary for the earthing conductor to be buried into the earth.
The resistance of the earth is reduced by pouring the salt solution into the earthing pit as the salt solution is a good conductor of electric current.
It will be small due to the great diameter of the earth. Even that has high resistivity material. Though it’s not like you could conduct information across the planet due to the number of space electrons have to travel
IEEE suggest the earth resistance value $5ohms$ or less

Note: Resistance is a property that depends on the displacement of the electrodes concerning each other. The Earth Resistance is calculated by using Ohm's Law. When An alternating current is passed through the outer electrode then the voltage is measured, through an inner electrode P, at some intermediary point between them