Useful resource on Power Quality, Radio Telemetry, T&M and Interfacing. Marc's Technical Pages; knowledge-base of Faultlink International, an independent electrical / electronics fault investigation & analysis consultancy.
Earth leakage currents arise mainly from the EMC filters built into electronic equipment with switched mode power supplies. Standards limit the leakage current from non-fixed equipment (i.e. equipment that plugs into a standard socket outlet) to less than 3.5 mA. When a lot of electronic equipment is in use, the total leakage current in the protective conductor can become significant. Power Electronics & Solar Energy