Mogweed wrote:
"The3rd Earl Of Derby" wrote in message
k...
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


You have to believe your instruments so I can only go on what the
megger tells me, and that says that there is no short - tried
shorting the test leads and the meter swings right over to 0 ohms so
the megger seems to be working OK. Cables capped - and chases
plastered over ( Some floorboards screwed back down - but
megger shows no shorts.

Mogweed.

Take the kitchen strap out of the CU attach a battery&bulb L to +, - to
bulb and bulb to N and see if the bulb lights? do this on the E to L and E
to N.
If it lights you have a short if not then start looking at CU

--
Sir Benjamin Middlethwaite