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WHAT WOULD YOU DO?

John Peckham
Today's job inspect and test a domestic installation in a sheltered housing flat. TN-C-S earthing system. Main protective bonding correct. 


Wet room for disabled occupant. Electric shower and extract fan supplied from a Wylex 2 way consumer unit  with BS EN 61008 30mA RCD main switch. Recently installed.


RCD does not trip on X1 RCD test but does trip on X 5 and operation of test button. RCD does not tip on a second and third test after X 5 test and operation of the test button.


Thinking about the Note to Regulation 643.8 are you content with this installation as there are no other observations recorded and prepared to issue a "Satisfactory" EICR?


  • 0
    If it is not operating at 1 x In, that suggests the RCD is not what "it says on the tin".  In effect its "operating current" is not known and what is written on the device makes no odds.

    So its 5 times of something....and not necessarily 150 mA, so how can you say it fulfills requirements for additional protection?


    So potentially dangerous, if additional protection is a requirement.
  • 0
    The R.C.D. is unreliable. It is not consistently reliable so needs to be replaced. It fails in its duty. One day it may fail when really needed. I would not trust it.


    Z.
  • 0
    As the modern day acceptable methods of disconnection under fault and shock conditions are not being met then it automatically fails its inspection. There is no room for compromise. oooh or is there?


    Legh.
  • 0
    You could code it as FI making it a fail and leave it to someone else to find out what the issue is.


    ?
  • 0

    Effectiveness is deemed to have been verified where an RCD meeting the requirements of Regulation 415.1.1

    disconnects within 40 ms when tested at a current equal to or higher than five times its rated residual operating

    current.




    well, to only do a 5 times test meets the letter of the regs. which I think is not really an adequate standard for a case like this, especially considering what is being protected.

    However, additional testing above the bare minimum reveals that it is clearly not working right after all, and really needs changing soon. 

    In your shoes I might do a a few  more tests to see what level it does trip at - if it fires OK at 35mA , it is less of an immediate  risk than if it still does not fire at 120mA.

    So assuming it does not pass close enough to 30mA that it could be tolerances on the test meter accuracy, then ..


    Report may have listed no failures against BS7671, if you had only done the minimum requred tests, but you tested more thoroughly

    and noted that the RCD protecting the bathroom is not operating as it should and needs replacement.


     


  • 0
    By the letter of 643.8, it might be a C3 rather than a C2, but I would strongly advise the landlord that the RCD needed to be replaced.


    I am inclined to think that any landlord who is getting EICRs is responsible and would, therefore, be keen to ensure that remedial work should be done at the earliest convenience.


    So John, what actually happened?
  • 0
    I'm sure John already tried this, but to be honest I've seen similar issues myself, which magically disappear when you use a different make or model of tester, or when you temporarily install the RCD in another location.


    I'm not convinced in these cases, whether it's some issue with an electrical waveform or interference, which is treated differently by the RCD, and/or the tester - i.e. the RCD may or may not be faulty and there's no way of knowing without sending it for extensive testing.


    I've had similar experience where RCDs pass x1 with flying colours, but fail x5 (and occasionally this is consistent with different testers).
  • 0
    What weighs the scales in this situation is
      .....a sheltered housing flat.


    Wet room for disabled occupant.

     



    If this was a bog standard wet room [ no disabled type hand rails and extra supports etc ] in a single household, the risk may not be so great and not so likely to be danger. A C3 could be issued with a bit more confidence.


    I personally do not think it hinges on 5 x  being okay. I know the regs use "rated", but surely the x 1 test is there to prove the rating of the device for purposes of 415.1.1.


    It could, after all , be a 100mA RCD in disguise?Airplane


    Also, this is "recently installed". So a decision was made to provide a 30mA RCD . There should not be the need for improvement. You have to default to there being a failure in the device operating at its rated operating current.
  • 0
    You also need to remember that even tripping at x1 will not protect all the population. Tripping only at x5 (or whatever the exact value is) will protect far less.


    Regards,


    Alan.
  • 0
    It could, after all , be a 100mA RCD in disguise?Airplane


    If I get these test results the first thing I check is that it is a 0.030A RCD and not an 0.300A RCD having been caught out in a gloomy cupboard under the stairs in a house some years ago, I also check the tester settings.


    But as this is JP it goes without saying the RCD rating and tester settings will have been double checked. ?


    Andy


    I was sat next to my wife on the settee last scrolling through the emojis and she asked what on earth I was doing, I replied I was looking through the choices of emoji on the IET discussion forum to reply to a post by JP she raised an eyebrow and said are there really emojis on the forum? Then raised it again when I showed her the choice.

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