Hzatph wrote:

We have two separate consumer units. One has a split load RCD and supplies
the back of the house - it has never tripped. The other is an older "fuse
wire" consumer unit with 16 circuits supplying the front of the house. It is
protected by an RCD on its incoming feed and it is this RCD that trips
several times per day.

16 circuits is quite alot to have on one RCD. It would be interesting to
carry out RCD test while on load to see how much extra leakage is
required to trip it.

There is no single cause that trips it - sometimes it is a light, sometimes
the computer, etc. What is really puzzling is that the TV can trip it. The
TV is in the back of the house fed from the other consumer unit and
therefore is not even supplied through the troublesome RCD.

The RCD has been checked with an RCD tester and it passed OK.

That does not mean that it is not pre sensitied by cumulative leakage
from all the circuits it is feeding to the point where it right at the
point of tripping with little provocation. You could try to isoate if
there is a circuit that is doing the bulk of the leaking by
disconnecting each in turn for a day and seeing if that reduces the trip
rate.

You did not mention what sort of supply you had, or the trip current of
the RCDs. Also what sort of circuits are fed from the re-wireable
consumer unit?



--
Cheers,

John.

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