Most Useful Electrical Testing Equipments - Clamp Earth Tester

Clamp Earth Tester :-

 

Stake-less testing is one of many methods of measuring earth electrode resistance. However what sets this method apart from all other earth electrode test methods is that it is the only method that does not require the use of auxiliary test electrodes or test leads. Since many earth electrodes are in locations surrounded by concrete or tarmac this is of real benefit. The lazy-spike method works well, but can easily be influenced by steel reinforcement or buried metal pipes. Using this clamp earth tester, it is very easy to measure the resistance of earth / ground electrode without disconnecting the electrode. 

Working Principle :-

Inside the clamp head of the earth tester, there are actually two cores. One core induces a test current and the other measures how much was induced. The input or primary voltage of the test current inducing core is kept constant, so the current actually induced into the test circuit is directly proportional to the loop resistance. This earth tester effectively makes loop resistance measurements. Stake-less measurements are loop measurements. There must be a series-parallel resistance path, and the lower the better. The more electrodes or earth paths in the system the nearer the measurement gets to the actual electrode under test true earth resistance. If there isn’t a loop to measure you could create one with a temporary jumper lead.