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Item 5.7, Regulation 411.3 on EICR on Inspection schedule

M Gilmore
Hi,


Hope you are all well and thanks in advance for your replies.


I came across an issue with the Inspection schedule for an EICR last week. When a measured value of PFC is higher than the protective device KA value installed within the Distribution board, I would flag a C2 observation (I think the classification of the observation is a different post....). I would add this to the C2 to the inspection schedule on item 5.7. My issue is the regulation number highlighted after the text for item 5.7. It is 411.3 which is the section for "Requirements for fault protection" I don't feel this really covers the observation. I would use regulation 434.5.1 which gives clear detail on the requirements for the "characteristics of a fault current protective device". I have had a look in GN3 and section 3.9.1 (Checklist of items that require inspection), this uses regulation 434.5 against the fault protection item.


Now, my question is, would you add the C2 observation to the inspection schedule and use regulation number 411.3 or would you leave the item off the inspection schedule and just record the observation using regulation 434.5.1? Or the final option, which is the one I went for, add the C2 to the inspection schedule but use regulation 434.5.1 on the observation


Hope that makes sense! I just wanted to get a feel for what other Inspectors are doing out in the field.


Cheers

Matt
  • 0
    Item 4.14 and section 432.
  • 0
    The second paragraph of 434.5.1 may well apply, and the co-ordinated arrangement of the two devices in series may well allow compliance, even if the downstream protective device is of a lower kA rating that would normally be allowed.  The operation of the upstream protective device may well limit the prospective fault current at the downstream device and protect it from destruction. It is unlikely that a bolted fault of negligible impedance will occur downstream of the protective device in many cases, so the energy is limited by the impedance at the actual fault position and the kA rating of the device may well not actually be exceeded in practice..


    Z.
  • 0
    P.S. Also, the kA rating of protective devices may well have been correct when installed initially, but if the supply has been reinforced by the addition of larger or more supply transformers making a larger P.S.S.C. than was initially allowed for.


    Z.
  • 0

    I came across an issue with the Inspection schedule for an EICR last week. When a measured value of PFC is higher than the protective device KA value installed within the Distribution board, I would flag a C2 observation (I think the classification of the observation is a different post....). I would add this to the C2 to the inspection schedule on item 5.7. My issue is the regulation number highlighted after the text for item 5.7. It is 411.3 which is the section for "Requirements for fault protection" I don't feel this really covers the observation.



    I'd agree that 5.7 doesn't seem to address a protective device with inadequate breaking capacity (more like an appropriate nominal rating & type for Zs and the required disconnection time).


    On a quick read, there doesn't seem to be an entry for inadequate breaking capcity - but then this form is only a model intended for domestic & similar situations - you're quite at liberty to add another entry if you think it suitable for your situation. In a domestic it's actually rather unlikely to hit this situation since practically all UK consumer units have a conditional 16kA breaking capcity rating - regardless of the breaking capacity of the individual MCBs or fuses within. So you'd be looking at situations where the PFC exceeds 16kA or is fed by something other than a BS 1361* fuse rated 100A or below, or for some reason don't have a standard CU type arrangement.

     

    * or whatever this week's version of the standard is called.


      - Andy.
  • 0
    BEAMA have an interesting paper which explains the subject of Short circuit back up and cable protection.


    I have attached it for your information.
  • 0
    I presume there is a fuse upstream of the breaker in question - if so check if that limits the energy  - it may be that a really solid short near the breaker takes the fuse out instead - not necessarily a problem.

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