How to check the Earth leakage on MCC panel. I got 70 V AC without Earth Connections. after the Connections ELCB (.03A) is tripping. So how can i Solve this problem

 

What type of MCC is it?

But i suppose you could start pulling buckets out and meggar the bus. Also might want to inspect the bus and the insulators, look for cracks in the insulators that would allow build up. I have seen insulators on dc motors crack and allow build up of carbon essentially creating a trace.