On Sun, 25 Nov 2007 15:32:32 -0000, "Tuthledeen" wrote:


"Mano" wrote in message
...
OK open to ideas here with this one :-

we have a mcb style mains board (crabtree from memory) which has an RCD
device built in. Normally when when for an example a bulb goes the trip
for that lighting circuit goes bit of a pain but we can live with it.
However yesterday and today has been a nightmare with the main breaker
tripping on average every two hours! No individual circuit goes and
throwing the break brings everything back to normal (apart from having to
reset the times on the cooker microwave stero etc!).

At a loss for any ideas. Nothing has changed regarding load no new devices
etc and its happened day and night so its not something we are manually
turning on or off.

any ideas where to start ?

Switch off individual breakers and see when/ if the problem goes away. After
determining the circuit at fault you can then isolate individual appliances
on that circuit until you isolate one that causes the problem to go away.
You then attend to that appliance. If you can identify an individual circuit
that has problems but no appliance has a problem, then you have wiring/
wiring fitting problems.

Bear in mind that this will not catch a neutral-to-earth fault though. If the RCD is tripping with
no other signs of problems ( bangs etc.!) , N-to-E shorting somewhere is a distinct possibility