Hi all, working in a house where a new kitchen is being fitted, have added and moved some sockets, c/unit to change next week. It's a TT system, earth was apparently by water main until changed to plasic a few years ago, since when no earth at all! Old Wylex 3036 board, looks like there was an old elcb at one time which has been replaced with a Henley block! (get's worse don't it). I've put a rod in, got around 150 ohms. Now to the point, in a fit of concience I decided to temporarily install a front-end 30m/a rcd. Strange thing is, the rcd won't trip unless the load is removed, I know this is how it should be tested anyway but it's a bit puzzling that it won't trip at all isn't it?. (tried another rcd) To re-cap, if I test at the rcd output with no load it trips well whithin correct times, if I now switch the main switch on it won't trip either at the rcd terminals or at a socket outlet. Zs at a socket seems ok at around 150 ohms, any ideas anyone? Makes me wonder what i'll find when I change the c/unit next week. Sorry for length of post but I wanted to explain it fully, regards.