1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

Failed EICR-is is justifiable to change RCD box(fuse box)

Discussion in 'Electrics UK' started by Iri, 31 May 2021.

  1. Iri

    Iri

    Joined:
    31 May 2021
    Messages:
    7
    Thanks Received:
    0
    Country:
    United Kingdom
    Here are the pictures
     
  2. Sponsored Links
  3. AndyPRK

    AndyPRK

    Joined:
    4 Jan 2009
    Messages:
    5,716
    Thanks Received:
    574
    Location:
    Herefordshire
    Country:
    United Kingdom
    we can see them in your previous post
     
  4. SFK

    SFK

    Joined:
    23 Jul 2010
    Messages:
    1,853
    Thanks Received:
    428
    Location:
    Oxfordshire
    Country:
    United Kingdom
    Screenshot 2021-06-01 at 15.16.10.png


    My DIYer background suggests that there should also be two 'real' blanking plates added to that CU to stop fingers touching internal live wires.

    Presume two of these should have also been added in the 'spare' slots:
    https://www.toolstation.com/contactum-mcb/p94598
     
    Last edited: 2 Jun 2021
  5. ericmark

    ericmark

    Joined:
    27 Jan 2008
    Messages:
    17,888
    Thanks Received:
    1,666
    Location:
    Llanfair Caereinion, Nr Welshpool
    Country:
    United Kingdom
    The EICR is not a fixed pass or fail like a car MOT, it is down to the inspector as to if he feels it is dangerous (C1) or potentially dangerous (C2) and stick tape over the unused slot for me would be a fail, would not expect any electrician to pass that.

    However as it if when fitted a RCD must work not so cut and dried. Personally I think all installations today should be RCD protected, and BS7671 talks about design, and it was clearly designed to have RCD protection on all circuits. And it says "Bed Lights" so seems likely that also supplies the bathroom and also likely bathroom needs RCD protection.

    I can't see why any Landlord would want to get out of renewing the RCD?

    I will admit I was rather surprised reading BBC web pages that it is so hard to evict a tenant. It does seem the Landlord has a raw deal.
     
  6. studentspark

    studentspark

    Joined:
    13 Mar 2010
    Messages:
    585
    Thanks Received:
    15
    Location:
    London
    Country:
    United Kingdom
    Unfortunately I don't think your installation has had an EICR. Just a passing glance.

    Did he have access to the Electrical installation certificate for the board. Wondering where he got the numbers from. If he didn't then it is a pure work of fiction.


    The schedule of inspections shows errors, eg. its ticking satisfactory for a surge device which does not exist, and that the IP rating of the CU is satisfactory, when there is a great big hole in it.

    That RCD is about £25.00 plus about £80 to swap it out. What were the numbers for the failed RCD?

    The EICR should take all day for that amount of circuits, and would be closer to £300.
     
  7. JohnW2

    JohnW2

    Joined:
    28 Jan 2011
    Messages:
    47,639
    Thanks Received:
    3,100
    Location:
    Buckinghamshire
    Country:
    United Kingdom
    Well, it is in the sense that any C1s or C2s mean that the installation is "Unsatisfactory" (aka 'fail'), whereas no C1s/C2s means that the installation is 'Satisfactory' (aka 'pass').
    As often discussed, that's no different from some aspects of an MOT. Just as with EICRs, there are things which cannot (or cannot easily) be quantified, hence subjected to proscriptive pass/fail criteria ('limits'), and which hence rely on the judgement of an inspector - e.g. the amount of play in a bearing or steering joint, the amount of corrosion of brake pipes, the degree of rust in body parts etc. etc.

    The big difference is that, wherever possible/practicable, MOT pass/fail criteria are proscriptively defined, whereas that is currently true of nothing in relation to EICRs - so everything on an EICR is down to (hopefully, but not always, sensible) 'judgement'.

    Kind Regards, John
     
    • Thanks Thanks x 1
  8. Licklieder

    Licklieder

    Joined:
    2 Oct 2010
    Messages:
    114
    Thanks Received:
    4
    Location:
    Surrey
    Country:
    United Kingdom
    Having read this thread with interest, and looked at the OP's EICR - isn't the PFC figure at the top of the second page also wrong ? I make the PFC 1.44KA for a Ze of 0.16 on 230V supply (230/0.16 = 1437). or am i missing something?
     
  9. EFLImpudence

    EFLImpudence

    Joined:
    7 Jul 2010
    Messages:
    36,381
    Thanks Received:
    4,070
    Location:
    Retired to:
    Country:
    Portugal
    You are probably correct but who knows which is the wrong figure?

    The PFC is the greater of PSCC and PEFC so it could be correct but as the installation is recorded as TN-C-S this is unlikely.

    Perhaps it is actually still TN-S but we are advised to treat such installation as TN-C-S.
     
  10. Sponsored Links
  11. JohnW2

    JohnW2

    Joined:
    28 Jan 2011
    Messages:
    47,639
    Thanks Received:
    3,100
    Location:
    Buckinghamshire
    Country:
    United Kingdom
    Your calculation is obviously correct. I suppose that, since those figures are "by enquiry or by measurement", it's just possible that the 2.5 kA figure was obtained 'by enquiry', but that's a bit far-fetched and probably unnecessarily 'generous' to the perpetrator!

    In an attempt to ascertain what the Ze action was, I've looked at the recorded R1+R2 and Zs figures, but the Ze implied by those is somewhat 'all over the place' (see below). A few are appreciably greater than 0.16Ω, whilst most are below 0.16Ω, some extremely low. The lowest (0.02Ω) would translate to a PFC at origin of 11.5 kA. ... so goodness knows what the Ze actually is.

    In passing, regarding circuits 12 & 13, is it really very likely that the 'Central Heating' circuit is a 32A ring, whereas the 'Bedroom Sockets' circuit is a 16A radial?
    upload_2021-6-3_13-9-29.png

    Since there is just one PEN at the origin of a TN-C-S installation, the PEFC and PSCC at the origin surely must be the same thing, mustn't they?

    Kind Regards, John
     
  12. EFLImpudence

    EFLImpudence

    Joined:
    7 Jul 2010
    Messages:
    36,381
    Thanks Received:
    4,070
    Location:
    Retired to:
    Country:
    Portugal
     
  13. JohnW2

    JohnW2

    Joined:
    28 Jan 2011
    Messages:
    47,639
    Thanks Received:
    3,100
    Location:
    Buckinghamshire
    Country:
    United Kingdom
    Yes, I read that before, but didn't totally understand it.

    It surely would not make sense to 'treat an installation as TN-C-S' if visual inspection clearly indicated that there was no G/Y connecting the cutout to the MET, would it?

    On the other hand, if inspection indicated that there was a connection between cutout and MET, then if there were also an (effective) TN-S connection to the MET ('in parallel' with the TN-C-S 'earth') then that would, indeed, result in the us usual situation of PEFC being greater than PSCC - but, again, that situation should be apparent on visual inspection.

    Kind Regards, John
     
  14. EFLImpudence

    EFLImpudence

    Joined:
    7 Jul 2010
    Messages:
    36,381
    Thanks Received:
    4,070
    Location:
    Retired to:
    Country:
    Portugal
    Ok. Strictly speaking I should have said:
    "Perhaps it is actually still TN-S but we are advised to treat such installation as PME."

    As there is no option on the certificate for PME perhaps it has been recorded as TN-C-S and it is this that is the error.


    Well, all sorts of things could be.


    I was merely pointing out that out of Ze 0.16, PFC 2.5 and TN-C-S, Licklieder was only considering that the PFC 2.5 might be the mistake.
     
  15. JohnW2

    JohnW2

    Joined:
    28 Jan 2011
    Messages:
    47,639
    Thanks Received:
    3,100
    Location:
    Buckinghamshire
    Country:
    United Kingdom
    I still don't really understand.

    A DNO-supplied 'earth' has to be either TN-S or TN-C-S, and that's all the installation 'knows' (or cares) about. 'PME' is something that DNOs do (have to do, at least in UK) to make TN-C-S a little 'safer' - but, again, an installation knows nothing about that. I suppose they could also 'PME' TN-S supplies if they wanted to, but I'm not aware of their doing that.

    The existence of the PME obviously means that the "N" component of "Ze" (or of an L-N loop path) will be at least a little lower than the "L" component, since the PME provides some 'parallel paths" for the N. However, again, an installation doesn't 'know' about that. In particular, it doesn't alter the fact that (with TN-C-S) PEFC and PSCC will be the same, since the ('PME') paths in parallel with the N supply conductor are part of the fault path in either case.
    Fair enough. In any event, we don't know where the 0.16Ω Ze 'came from', and the figures I posted above indicate that the recorded R1+R2 and corresponding Zs figures do nothing to support any particular value of Ze - as I showed, the figures for one of the circuits suggest a Ze of 0.02Ω, which would lead to a PFC at origin of 11.5 kA !

    Kind Regards, John
     
  16. EFLImpudence

    EFLImpudence

    Joined:
    7 Jul 2010
    Messages:
    36,381
    Thanks Received:
    4,070
    Location:
    Retired to:
    Country:
    Portugal
    As I understand it, the fact that the DNOs have neglected to maintain their TNS sheaths means that that sheath is connected to the Neutral conductor - somewhere.

    Because of that apparent TN-S supplies should be regarded as TN-C-S and/or PME.

    Not at the premises but - somewhere.


    Once again - I was merely pointing out that the mistake in the figures could be because of multiple reasons; not dividing 230 by 0.16 and getting 2.5.
     
  17. JohnW2

    JohnW2

    Joined:
    28 Jan 2011
    Messages:
    47,639
    Thanks Received:
    3,100
    Location:
    Buckinghamshire
    Country:
    United Kingdom
    I'm not sure what real difference that makes to anything - after all, a TN-S sheath is always connected to the neutral 'somewhere', even if only at the tranny.
    That's the bit I'm having difficulty with - 'regarded' by whom, and in what context(s)?

    For what it's worth, and as you know, in at least one context (specifying minimum CSAs for main bonding conductors), BS7671 does not require TN-S supplies to be 'regarded as' PME.
    ... and, also 'once again', I agree with you. In fact, I'm not sure that the original suggestion was that it was necessarily the "division sum" which was wrong - merely that 230V, 0.16 and 2,500A do not 'work together' :) ... which, as you say, means that the 0.16 and/or 2,500A figures must be 'wrong' (and remembering that, at l;east in theory, either of both of those recorded figures could have been ascertained 'by enquiry').

    Kind Regards, John
     
Loading...

Share This Page