ABSTRACT
Many electrical installations contain earth electrodes, which are relied on to make a good connection between the installation's earthing system and the general mass of earth. The purpose of the earth electrode resistance test is to measure the resistance between the earth electrode and the general mass of earth and compare the measure value with the maximum values specified for each application. Earth electrode resistance can vary due to soil drying and freezing, so ideally testing would be carried out under least favourable conditions. In practice, however, this is rarely possible so the tester must consider the effect of soil condition on any reading obtained. Test E1 requires the use of a dedicated earth electrode resistance tester and involves the use of temporary test spikes inserted into the ground to measure the resistance of the electrode under test. Test E3 is used solely on TT earthing systems that are connected to the electricity supply network.
