Sorry guys, been away on a course. It was good of you all to respond.
Ok, between myself and the site spark we have established that take the genny spike out, rcds trip - not always but often. Put the spike back (and its actually just pushed into soft earth adjacent the generator housing)problem resolved. RCDs ARE ELECTRONIC and are of course,placed downstream of the 4-pole change-over switch. Trumpy, Paul; genny is star connected. Neutral connected to frame and thence to installation earth. Paul Cornwall; I cant see how the two earths would be separated lest a link was fitted. I think this arrangement is only used where harmonics are of a concern on parallel sets. UK Sparky, I need to think about what you are saying before further comment.
I do appreciate all your comments.
