A 3 phase test is required for 3 phase electrical equipment. The test requires an earth leakage test performed using appropriate testing equipment, to ensure that dangerous currents aren’t detected and appliances aren’t faulty. The technician will look for any current over 5mA, which is deemed unsafe and therefore won’t pass the test.
Upon completion of the earth leakage test, an earth continuity and insulation resistance tests (IR test) is done. The earth continuity test is designed to measure and test the resistance of the protective earth of the appliance and/or the supply lead. The test is performed by measuring between any accessible earthed parts and the earth pin of the appliances plug. The insulation resistance test is performed by testing the integrity of any wires or cables of the appliance.
If the appliance passes all three tests, the technician will then tag the appliance, deeming it safe for use.