Trying to figure cause of tripping

[coolsparx]

RCD sockets & spurs, surge protected leads & USB sockets all play havoc on test results if not found & removed prior to testing.

 

[Gavin John Hyde]

Those initial IR readings, in the 1-3MΩ range, what was causing those - the pumps, socket or immersion? Clearly even 0.9MΩ isn't going to affect an RCD much with 0.26mA of leakage, but they are low enough to suggest a problem worth finding.

When i took the rcd socket out of the circuit the readings all went upto the 199 range. So clearly the rcd socket was causing issues, for some reason the socket tripped the main cu rcd. as the pumps on a newly installed standard socket did not trip the cu rcd. which indicates problem being the rcd socket.