"John Rumm" wrote in message
o.uk...
Do you actually mean MCB or do you mean the RCD in the house?

My question is am I likely to have found the problem? I can keep
checking

You have found a problem (well two in fact). But whether they are
connected will depend a bit on the answer to the above.

I have looked again at my house CU and I think I may have lead certain
people up the garden path due to my lack of terminology/knowledge with
regards to MCB's and RCD's.

The CU is 17 years old and is an MK Sentry. The trip switch in question is
actually a RCBO. The details on the breaker a

[Test Button]
[Switch]
RCBO
LN 6930S
16A 30mA
Type 2
240V

I believe the 6930s is the Old MK part number but it now appears to be
superseded by 6934s. Only my house sockets, (1 upstairs and 1 downstairs)
and my garage are protected with this type of RCBO. All other circuits are
just MCB's (2 x 6A, 1 x 16A, 1 x 32A) and a 100A big red switch for
everything.

Cheers

John