Mogweed wrote:
A mate of mine has completely rewired our house so everything in the
installation is brand new, including the split-load consumer unit. We
have an upstairs ring main, downstairs ring main and a kitchen ring
main, all of which are protected by the RCD, and the problem is the
kitchen ring.

As soon as *anything* (portable radio, halogen lamp, electric drill or
whatever) is plugged into *any* socket on the kitchen ring, the RCD
trips (plugging the same things into either upstairs or downstairs
rings does *not* trip it).

Splitting the ring at the CU and using a proper Megger (500v
insulation resistance tester, not just a multimeter) to test each leg
of the ring shows the following:

L-N = almost infinity resistance (certainly over 1,000Mohms anyway)
L-E = " " " " "
" "
N-E = " " " " "
" "

so no short-circuits, but yet the RCD trips. What's the problem - more
importantly, what's the solution to the problem? )

TIA,

Mogweed

Are you 100% sure you don't have a short?

Have you been capping back the cable into chases, Screwed down floor
boards?
--
Sir Benjamin Middlethwaite