Earth tester

An earth tester, or earth resistance tester, is designed to measure resistance similar to a megger, except that the earth resistance is much lower than that of conventional insulation. In fact, the megger’s range is in the megaohm range, and the earth resistance tester’s range is in the ohm range.
An earth resistance tester is usually used to measure the resistance between two earth points, which is about 5 or 10 ohms.
Earth testers usually have three connections that can be connected to the earth using a metal rod and are known as current, ground, and potential electrodes.