"Terry Pinnell" wrote in message
...
Terry Pinnell wrote:
Morse wrote:
Terry Pinnell wrote:
Thanks for those prompt and helpful replies. I'm responding to the
requests for more info:
The unit is a 'Crabtree', and carries a label '8A/30mA'.
Is this the SB6000 series by any chance, or at least that series/vintage?
(20 years old or more I'd think now!) There should be a label somewhere
on
the fascia.
If so, these are known to get 'twitchy' as they age, the breakers trip
for
no apparent reason and the only cure is replacement. However, I'm not
sure
the individual breakers are available now, you may have to replace the
whole distribution box if it becomes troublesome- like I did!
If the problem reoccurs regularly it would be wise to consult an
electrician
and get a quote. If it's just the immersion heater circuit though, you
may
choose to just live with the minor inconvenience if it isn't regularly
used
and spare breakers can't be sourced- changing the whole distribution box
isn't cheap!
Morse
Thanks for the follow-ups. I'm going to have to do some more careful
reading, maybe starting here
http://wiki.diyfaq.org.uk/index.php?title=RCD
as I don't really understand the basics, and hence some of the advice
given. Meanwhile, beginning to regret switching from my old fuse-based
unit a year or so ago!
The Crabtree is a modern modular unit, but so far I've not found its
spec. I'll do so as soon as possible and report back.
I've also taken a photo and labeled it as per my previous post.
http://www.terrypin.dial.pipex.com/Images/CU-1.jpg
(BTW, MCB #5 on the RCD side is disconnected.)
Note that I realise that the RCD controls electricity to all the MCBs
on the RCD side of the unit (not just the immersion heater). But I
think I was correct in my recollection that the only switch I reset in
the Crabtree unit was the RCD one.
--
Terry, West Sussex, UK
It could be that you had a brief general (street-level) outage, and that
when it came back on, for whatever reason, it tripped out the immersion
heater MCB. You would have expected that for that to happen, the immersion
switch would have needed to be on, but odd things like this can happen,
particularly if it is just a single pole switch. MCBs can be sensitive to
the strangest (non) fault conditions. If the consumer unit was replaced
recently by a reputable certified electrician, then there's a good chance
that there is nothing wrong with the wiring to it. A decent electrician
would probably have checked the external circuits for leakage whilst he was
doing the job. I think if I was in your position, I would probably wait and
see if there were any more 'events', but if you would prefer total peace of
mind, I wouldn't have expected it to cost *too* much to get an electrician
in (probably not the original guy, just in case, unless you know him and his
work well) to just check over the immersion circuit in particular for
leakage. I honestly don't think that he would find anything, because if your
recollection is correct, and you had a total power outage, but the only
thing tripped was the immersion MCB, I can't see any way that this could be
for any other reason than the actual feed to your house dropping out. The
fact that you had a 'known' outage the next day which was due to the feed
dropping out, might well suggest that the electricity company were either
doing some work on the loop that feeds you, where they often 're-route'
temporarily to kill the section that they are working on, whilst keeping the
subscribers live, or else that they were having some tripping or equipment
issues of their own. When these big old company breakers remake, they can
generate some pretty big spikes. I have a national grid switching station
not far from me, and when they have any switchover or breaker issues, it
lights up the sky like lightning !!
Arfa