Cause : Ext earth leakage comes when external earth fault trigged by input selected with parameter 131.28 Ext earth leakage signal source.

1. Check external earth fault source.
2. Usually only one device is allowed in the same network.
3. Check AC fuses. Check for earth leakages.
4. Check supply cabling.
5. Check power modules.
6. Check there are no power factor correction capacitors or surge absorbers in supply cable.