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Recommended checks before CU change

Former Community Member
Former Community Member
As most of you know I’ve only been qualified for just over a year and I’ve got a quote to do for a cu upgrade.


I know I’m nowhere experienced enough to do EICR’s yet, but what would you guys recommend I check/test before doing the cu upgrade and should I do these checks/tests at the quote stage?
  • 0
    What Voltage did you do the L to N test at? I do hope it was not 500V !


    Whoops . Seems like the question has been asked and answered ?
  • 0

    Fitzy71:

    . . . I did how ever get my first electric shock ‘TWICE’, as I was holding the L cables in the mcb holder to tighten the little screws, my little finger brushed the incoming Live tail.  Does that make me a proper sparkie now then?  ? ? ?




    No, but under slightly different circumstances it could easily make you a dead sparkie.


    Regards,


    Alan. 

  • 0
    Alan is correct there Fitzy. In my adult life I`ve never had an electric shock except when someone has played that age old game - catch the capacitor (throwing a charged capacitor gently towards you and you instinctively attempt to catch it,) ouch 500V in a 1uF capacitor does hurt even on my dry skin.


    As a child, in hospital early moring, I attempted to plug TV in . Little fingers and non sleeved pins on plugtops were not a good combination. Not only hurt but freetend me to death.

    Without that lesson would I have got an accidental shock later in adult life? Quite possibly.
  • Former Community Member
    0 Former Community Member

    ebee:

    What Voltage did you do the L to N test at? I do hope it was not 500V !


    Whoops . Seems like the question has been asked and answered ?




    This is with the main cover removed, then I removed the little grey cover from the centre switch to do my Ze.

    addb4bfbfc99a83a7380640142f8514a-huge-443bd5de-3b3c-4863-a11f-66a03756c6c8.jpg

     

  • 0
    For a Ze test, to do it safely you could use a longish insulated probe for the L connection, with a very short exposed tip.  Main switch OFF, carefully disconnect the main earthing conductor, carefully connect croc. clip to separated main earth conductor first, then apply  insulated probe to L of incoming supply. Then test. No fingers needed near live parts.


    After test, remove insulated probe first, then earth croc. clip secondly.

    ...............................................................................................................

    Always connect the safest clip/probe first ( E or N) then the more dangerous one (L) afterwards for the test.


    Always disconnect the most dangerous connection (L) first and the safest one (E or N) last immediately after the test.


    Z.
  • 0

    Fitzy71:

    This is with the main cover removed, then I removed the little grey cover from the centre switch to do my Ze.




    And then?

  • Former Community Member
    0 Former Community Member
    Then I forgot to put it back on when I was doing my rfc continuity tests to the circuits on the right of main switch and little finger brushed the live tail. 


    The big big question now though is:


    As the IR figures were really low (0.42mohms), do I quote not to get the job, quote to get the job and hope the IR is good after all or quite and include extra for the extra remedial work and if not needed, don’t charge?


    As I need this job for my reassessment, I’m thinking quite with a few extra hours included for potential remedial works, or even bite the bullet and quote for just the cu replacement.


    Luckily, I have a full time job, so by just doing any remedial work won’t actually lose me any money, just my time. 

  • 0

    Fitzy71:

    Then I forgot to put it back on when I was doing my rfc continuity tests to the circuits on the right of main switch and little finger brushed the live tail. 




    That's why you should do dead tests before live tests!

  • 0

    Fitzy71:

    . . . As the IR figures were really low (0.42mohms), do I quote not to get the job, quote to get the job and hope the IR is good after all or quite and include extra for the extra remedial work and if not needed, don’t charge? . . . 




    The whole idea of the pre-tests is so that you can give your customer a reasonably accurate quote. Whether or not you choose to ignore / believe the figures you have is a business decision by you. What is your contingency for example if you do just a board change, then are unable to get the rcds to stay closed, so your customer is without light and / or power? 


    Regards,


    Alan. 

  • 0

    Fitzy71:

    Then I forgot to put it back on when I was doing my rfc continuity tests to the circuits on the right of main switch and little finger brushed the live tail. 




    Fitzy, hopefully you realise you made a mistake, this time you got lucky! There is a sequence for tests, had you followed them you it is quite likely you would not have put yourself in danger. For a quick refresher look at this https://youtu.be/Sc0tJGl4Oas




    The big big question now though is:


    As the IR figures were really low (0.42mohms), do I quote not to get the job, quote to get the job and hope the IR is good after all or quite and include extra for the extra remedial work and if not needed, don’t charge?


    As I need this job for my reassessment, I’m thinking quite with a few extra hours included for potential remedial works, or even bite the bullet and quote for just the cu replacement.


    Luckily, I have a full time job, so by just doing any remedial work won’t actually lose me any money, just my time. 




    As as already been said, you need to make a business decision is it worthwhile for you do the repairs and what to charge. It could be a full rewire or simply fixing a nicked cable in a backbox. Had it been my job, I would have taken time to identify which circuit(s) was giving the low reading. Then I would have had a discussion with the customer about my recommendations and costs. This may not be the job for your reassessment?


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