On Tue, 23 Aug 2005 21:23:02 +0000 (UTC), "Hzatph"
wrote:


Pete - you are correct in your statement that it is switching the TV on. I
wonder about a neutral connection and also about the degauss type effect.
Thank you. We are going to change the 30mA RCD for a 100mA one and replace
the fused consumer unit with a modern one with 30mA RCDs on the ring mains
and power spurs.This should ease the problem we hope, and it if continues to
happen then we will have a better idea of where the fault lies.

Hi,

I'd expect there is a neutral-earth short somewhere as others have
said. When you switch the TV on the current surge probably puts a
small voltage on the local neutral which causes more fault current to
flow through the short to earth and trip the RCD, even if it's in the
other CU as the neutrals are commoned.

I'd get another better electrician to look at it, describe the
symptoms to them and see if they mention the above. It should be
possible to find the fault by disconnecting each neutral in turn and
checking for a short between it and earth. While doing so any
connected equipment should be plugged in and any isolators switched on
initially in case the fault lies there.

Changing the CUs is just treating the symptom of the problem instead
of the cause, a good electricial might find the fault within an hour
or less. If your current guy can't diagnose or find a N-E fault then
getting him to change the CU might lead to other problems...

cheers,
Pete.