Generator to Main changeover issue RCCB not moving up
I found the issue, first MCB in lighting line is the cause, means, when I turn off 1 st MCB in the lighting line, immediately after Mains changes to DG, then there is no tripping when DG changes to EB. 

This means, the issue is happening in the 1st MCB circuit, there is some device, in this circuit I need to see , it's touching the ground, which caused the tripping of RCCB.