On 21/10/2017 13:14, Yam man wrote:

replying to John Rumm, Yam man wrote: Hi John I have traced all my
new wiring back and disconnected the fused spur from my sockets I
have removed both fuses from the 2 lights I added. The tripping got
worse to the point last night we couldn't reset it as it tripped
straight off. I've tried switching different breakers on and off it
will still trip even if all breakers off and just main switch rcd on.

If its tripping with *all* the MCBs off, then that suggests its most
likely a faulty RCD. (RCDs work by sensing an imbalance between current
flowing in the live and neutral - with all the MCBs off then there
should be no current in either in the absence of some other more
esoteric fault)

You could prove it if you are happy to open the consumer unit itself.

With the main switch off, and all MCBs off, you could disconnect the
neutral out of the RCD where it connects to the neutral bus bar (it will
be a big thick black/blue wire that normally drops out of the bottom of
the RCD and goes up to the bus bar where all the circuit neutrals end).
Then if you switch on the RCD, then the main switch, and still get a
trip, its knackered.

You mentioned that the RCD was one with a 100mA trip threshold... That
seems slightly odd, since you would only normally see that on places
that don't have a proper earth provided by the electricity supplier, and
as a result need to reply on an earth stake (what's known as a TT
system). Is this the only RCD you have or are there others?

If its the only one you have, and you are *not* TT, then its not
actually doing you much benefit anyway (the trip threshold is too high
to protect you from a lethal electric shock). So you could safely simply
bypass it.

Have a look at:

http://wiki.diyfaq.org.uk/index.php/Earthing_Types

(might be handy if you post some photos of your fuse / meter / CU if so
we can be sure)

I fitted 5 new socket fronts around house at same time and disposed
of old 1s. All are single pole double sockets. I've removed them all
and put block connectors and covered in insulation tape. I'm now got
downstairs lights and sockets only and it still trips. Any ideas
insight advise on what I can do greatly appreciated. Did manage to
get multimeter but red prong is missing it's just bear wire to use.
Will get 1 tomorrow morning.



--
Cheers,

John.

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