Ground resistance testing principle base on the ohm’s law. Insert 4 electrode deep into the ground surface, marked with E1, P1,P2, E2, 20meters far each, as below:
AC signals act on electrode E1 and E2, pass through electrode P1 and P2,current flows cross the earth will being measured with the meter, if the current value is constant, then the obtained voltage will be proportional to the earth resistance.
The displayed value depends on the inner swamping resistance, so please choosing the right measuring range accordingly. AC signals generates from the inner convertor.
