Any electrical circuit needs a good electrical ground. An electrical ground serves as the return path for the circuit, protection against shock in case a wire opens and it bypasses electrical noise to the earth. It is important that the ground stake has good contact with the earth to ensure stable operation of the electrical system.
To test for ground reliability, the resistance is measured. Ideally, the ground and the lead wire should have a low resistance. If the ground stake is not well inserted to the earth, the resistance may increase. The common method for measuring resistance is through a 3 or 4 terminal method. However, this method may be time consuming. If you want to measure earth resistivity quick and easy, consider getting the AEMC 3711 Clamp On Ground Resistance Test Set.
This tester allows you to measure resistance down to 0.1 Ω with a resolution of 0.01 Ω. It also allows fast resistance measurement with its 1 second setting time. It is immune from electrical noise which makes it ideal for use in electrical distribution facilities and transmission towers.