Earth Overlap Test

Earth Overlap Test Points : Earth Overlap Test In the “earth overlap” test, the two measurements made are: First, the resistance M₁ between line and ground, measured from the “testing end”, with the far end earthed; and then the resistance M₂, line to ground, measured at the “far-end”, with the “testing-end” earthed.

In each of the above tests, the distance of the fault from either end is obtained from the resistance between the fault and the end by using the known value of the resistance per unit length, of the fable. The accuracy of these two methods is not high, mainly because it is often difficult to make connections to earth, at the ends of the cable, having a low enough resistance for this to be considered negligible.