Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 157 replies
  • Subscribers 32 subscribers
  • Views 9771 views
  • Users 0 members are here
Options
You may also be interested in
This discussion is locked.
You cannot post a reply to this discussion. If you have a question start a new discussion

Ring Main at Consumer unit

Former Community Member
Former Community Member
My daughter has just had an electrical safety check done and I suspect that the electrician has been over zeleous..

Would anyone care to comment.


There is no grommet where the meter tails enter the consumer unit and the outer insulation stops just short of the knockout.

He has graded this C1.   Now my opinion is that that does not present an  an immediate threat to the safety of personell

It needs fixing but surely only a C2?


More intriguing.  He gives a C3 to the ring circuit because the two legs enter the consumer unit through separate knock outs.  I can't find that in the regs


And finally an old chestnut which has been discussed before.   A C3 because two radial "circuits" are served by a single breaker..  I have always argued that the definition of a circuit is that it is served by a single breaker.  Certainly if both radials were brought to a junction box outside the CU and then connected to the breaker by a single cable it would meet the definition of a radial..


Thanks for your attention

  • 0
    I do need to urge to to be very careful if you are going to try and manhandle these tails back into the consumer unit enclosure.


    It is not at all unusual to find that the person who stripped the sheath back ran a very sharp knife around the cable and sliced into the inner insulation. You really need to check that the inner insulation is sound at the point the sheath ends.


    Personally I only strip sufficient sheath to allow the termination of the cable into the main switch, usually 10 mm or less, I cannot understand why some people strip the sheath right back within the enclosure removing the mechanical protection from the insulation for no apparent reason.
  • 0
    1e1f2503c18ea0de2400b9bb5a35f360-original-20200127_135339.jpg
  • 0
    An extreme example, but basically a warning that you should treat every electrical installation as though it was installed by an idiot.
  • 0
    Sparkingchip:

    I do need to urge to to be very careful if you are going to try and manhandle these tails back into the consumer unit enclosure.


    It is not at all unusual to find that the person who stripped the sheath back ran a very sharp knife around the cable and sliced into the inner insulation. You really need to check that the inner insulation is sound at the point the sheath ends.


    Personally I only strip sufficient sheath to allow the termination of the cable into the main switch, usually 10 mm or less, I cannot understand why some people strip the sheath right back within the enclosure removing the mechanical protection from the insulation for no apparent reason.


    Lucky it’s pretty rare method of install of tails, but I was thinking why the outer sheath had been removed so far back. Perhaps the entry hole with the grommet was to small? At least we can now see why tail glands are such a good idea. 


  • 0
    To really put that picture of the sliced cable insulation into perspective it's the rear tail of these, a classic example of how not to make off the cables into a double pole Henley block. I always put the lives at the back where there’s a longer cable entry tunnel and never leave single insulation exposed. It’s not hard to do a tidy job.

    f3fee492aadb73273cdd7699cc7f414b-original-20200127_095114.jpg


  • 0
    In a high level cupboard in a kitchen, I repositioned the Henley block, and tidied it up, replacing one set of tails completely which is why I have a photo of the removed tails.


  • 0
    Hopefully the case in question is not quite as rough as that.

    But even if it was that rough, that does not warrant moving house while it is fixed, just being aware and keeping an eye on who has access to it until it can be made good..

    (And the instant temporary fix to demote a C1 to a C2 is a turn of self amalgamating tape or that awful putty like stuff you sometimes see that ruins perfectly good trousers)

    It is quite common to have a flash of colour on show  for the last cm or so with the  grey tails cut slightly short to identify the polarity of the  core within.

    Not really the way to do it, and personally I prefer a turn of the correct coloured tape, but I am not everyone.


    Mind you the gap between the ideal and what remains actually still more or less safe in practice is quite large.

    To set an expectation of what fok can live with for years, without having to moving out while it is fixed, this picture is from another thread showing some wiring in Azerbaijan.

    Certainly a lot of Eastern Europe wiring was like that before the fall of the iron curtain, though most of it has now been improved, but even back then accidents were pretty rare, but perhaps folk were rather more clued up to be careful and did not expect things to be intrinsically safe and to work unattended.

    2b90d36a2fe35ef699aae16b9c42d48c-original-worst_case.png
  • 0
    Sparkingchip:
    1e1f2503c18ea0de2400b9bb5a35f360-original-20200127_135339.jpg





    If you look carefully you can see the copper conductors were actually scored with the knife, you really would not want to be trying to manhandle these back into a metal enclosure.


  • 0
    Indeed. For one like that if I absolutely had to, I'd consider tape to make it safer for a few days, the long term  fix is to cut back and re-terminate  or replace . You have to wonder what some folk are thinking of when they leave jobs like that - did they not see it cut through to the metal ?


    Mike.
  • 0
    Sparkingchip:

    Personally I only strip sufficient sheath to allow the termination of the cable into the main switch, usually 10 mm or less, I cannot understand why some people strip the sheath right back within the enclosure removing the mechanical protection from the insulation for no apparent reason.


    mapj1:

    It is quite common to have a flash of colour on show  for the last cm or so with the  grey tails cut slightly short to identify the polarity of the  core within.

    Not really the way to do it, and personally I prefer a turn of the correct coloured tape, but I am not everyone.

    I agree that the removal of only sufficient outer sheath in order to be able to identify the tails is best, but I fail to see a problem with removing more inside the CU: it does reduce the bulk.  My firm preference is to use a gland so that they may not be pulled outwards and especially for mechanical protection in a TT system, but it does require extra work and a very modest additional cost.

Join us to get the best from IET EngX.

Joining EngX lets you personalise your experience so you stay up to date on the topics that interest you, plus you’ll be able to make connections who are looking to collaborate, exchange ideas and more.

Join us Not now

Community Rules & Guidelines