3 Phase External Earth Fault Loop Impedance Test Live testing for external earth fault loop impedance on a 3 phase supply. This test is demonstrated on a live 3 phase distribution board and will help with AM2 and AM2S exams. As always preparing for your end skills test AM2, AM2S or AM2E requires time testing at college and on-site experience of testing electrical circuits. NOTE - Your end point assessment AM2 and AM2S will require you to have the main switch locked off, sign in place and key In

Earth Fault Loop Impedance Test - 3 Lead Low or 2 Lead High - Test Explained In this video Marcus explains what happens when we would set our MFT tester to 3 lead low, 2 lead high and even 2 lead low in order to carryout an earth fault loop impedance on a circuit that has RCD protection. So we can carryout a earth fault loop impedance test it is important to select the correct setting on an MFT tester but do you understand why we often select 3 lead low setting when testing for earth fault loop