Do you know how to measure the earth resistance?
Actually the Earth resistance is measured using “earth
resistance meter”. You might think about megger is correct answer but megger is used only for high resistance
measurement i.e. in Mega-ohms but when considering upon
earth resistance it should not exceed 1ohm so earth
resistance meter is required.
In this meter, there will be four terminals(E, P1, P2, P3)
in which E and P1 will be shorted and connected to the grid
or electrode and P2 and P3 are reference electrodes which
will be kept on the earth surface on two different
locations for taking the reference resistances of the earth.
The meter shows the resistance of the earth. But it is
necessary that it should be below 1 ohm.