Measuring earth leakage current in 5kW off grid inverters.

The images below are taken from our laboratory while we have been testing the leakage current from a 5kW inverter with dual MPPT input. The critical point is the AC input where a generator is connected for back up power.

In off grid solar systems, RCD protection should be connected only to the AC output of the inverter to protect the consumers. The AC input (generator or grid connection) is fitted only with a standard MCB device without earth leakage protection.

In the present set up we measured a very low current flowing from neutral to earth of 17mA only.