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Multicore cables (YY but not PVC/PVC)

jbrameld
I wonder if I could previal for some learned opinions.


We undertake installations of stage lighting amongst other things, and often use a 19-core 'YY' type cable (though it isn't really YY as the insualtion and sheathing is not PVC/PVC - it is a LSF variant) for links between switched power units or dimmers and internally wired lighting bars.


We have undertaken many such installations, and we are registered with the NICEIC who have audited and inspeced many such installations and passed them.  We have also raised specific questions with them on the use of the cable and we get varying answers.  They are never willing to give an emphatic 'yes', but neither do they say 'no'.


As I understand it - there is not a relevant construction standard that covers this type of cable construction, so it can't comply with a standard that doesn't exist.  There are however many standards (many of which form normative references for construction standards of other cable types) with which it does conform.  These include EN 50525-1 (General requirements) EN 60228 (conductors) and various fire performance standards (EN 50575, EN 60754, EN 60134 and EN 60332).  We also know that the insualtion and sheathing material is standards-compliant and is commonly used in cable manufature.


We are embroiled in a dispute with a main contractor who is claiming the installation is non-compliant as the cable does not meet a construction standard. Reg 511.2 allows for use of euipment not covered by a Britsh or Harmonised standard if the designer/specifier confirms that the equipment provides at least the same degree of safety.  This cable is covered by multiple standards but not a single 'construction' standard that is applicable to this type


We have undertaken what we believe to be a thorough assessment of this cable which is attached here:  Assessment of Cable NILTOX LF 319.docx


The use of the cable is noted on the certificate and the assessment and supporting documentation from the supplier is attached, but the main contractor is still refusing to accept this route.


So a couple of questions for the learned community:
  1. Have we missed anything in our assessment, or does it seem thorough and complete?

  • Should the use of this cable be recorded as a 'departure' (our agument is that we have complied with 511.2 and therefore it is not a departure) or just recorded as a note?


Thanks in advance.  Happy to answer any further questions.


Jason.
  • 0
    Graham - So having looked in the OSG, this appears to be a case of the OSG asking for things that are not stated as required in BS7671 - such as independent testing organisation approval.  The guide makes no reference to the compliance route of an equivalent safety assessment which is clearly referenced in BS7671 and is the route that we are taking here.


    I understand that the on site guide is intended to provide a simplified approach to compliance, but it is generally recognised that this is one of many possible routes.


    In this case, the cable has been independently tested by BASEC for fire performance (we have that documentation) and relevant traceabiliity is provided through a manufacturers marking on the cable (NILTOX LF-319 12 X 1.5 mm2 LOW SMOKE HALOGEN FREE 90 deg C BS EN 60332-3-24 Cat C 61034-2 & 50267-2-1&3 CPR Class Dca s2,d2,a1 CE RoHS3 FT0013695) and the associated quality control reports, data sheets and quality test plans that are appended to our documentation.


    I do find the wording relating to 'standards compliance' to be very wishy-washy.  We have a comprehensive list of 

    standards that this cable does comply with and has been tested to.  The OSG says 'every item of equipment must comply with a British or Harmonised standard' - on face value the cable meets that test multiple times.


    Jason.
  • 0
    The OSG can be thought of as a Regs Lightweight, containing standard recipes for folk who have no desire, and in some cases perhaps no ability, to go beyond installing standard designs and using standard parts, in standard ways. After all that is probably 99% of the electrical work out there.


    To follow the OSG is nearly always a safe path, it is not necessarily the only (or the best) way to go about things that BS7671 would permit. (We shall ignore for now that BS7671 is also not always the best way to go about things either in a few corner cases, as you are contractually beholden to it, but presumably not to the OSG.)


    As such the OSG cannot present a full set of off the peg solutions to this sort of case - large companies may have their own test facilities for example (my name appears in the paperworks of a few CE marking declarations for some experimental equipments for example) so in those organisations to use some funny  novelty may be as simple as testing it and then becoming the manufacturer or importer of that part and legally responsible for it.


    This path of self testing of components is not open to the average contractor, so the OSG very sensibly suggests that you need a paper trail from the makers.


    However, you are not quite in that case either.

    Mike.
  • 0
    Hi MIke,


    I entirely agree.  We're adopting the 'equivalent safety assemment' route - permitted in the regs, but not mentioned in the OSG.


    We do have a fair paper trail from the makers - including their Declaraiton of Conformity, detailed test schedule, quality control test verification sheet and BASEC test report on the fire performance of the cable (information from all of which fed into our equivalent safety assessment attached in the OP)  I'm struggling to see what's missing from the picture!


    Jason.
  • Former Community Member
    0 Former Community Member
    jbrameld:


    We do have a fair paper trail from the makers - including their Declaraiton of Conformity, detailed test schedule, quality control test verification sheet and BASEC test report on the fire performance of the cable (information from all of which fed into our equivalent safety assessment attached in the OP)  I'm struggling to see what's missing from the picture!


    Jason.


    Hi Jason, I don’t believe your cables are subject to BS7671 so perhaps the mistake is to claim they comply?


    How do you note this kind of cable installation usually on an installation certificate, ie from a dimmer to an IWB?


  • 0
    Well there's an interesting thought.


    Often these days the dimmers are running in bypass so they are effectively expensive distribution boards, or are just being used to switch 'hard power' to LED fixtures as tungsten dimming is rather passe now.


    They are generally tested and recorded as indivdual circuits from the outlets on the bar - as if they were radials.


    Jason.


  • Former Community Member
    0 Former Community Member
    jbrameld:

    Well there's an interesting thought.


    Often these days the dimmers are running in bypass so they are effectively expensive distribution boards, or are just being used to switch 'hard power' to LED fixtures as tungsten dimming is rather passe now.


    They are generally tested and recorded as indivdual circuits from the outlets on the bar - as if they were radials.


    Jason.


     


    Thanks for the reply Jason, when you say “as if they are radials” ,is the electronic equipment active during the tests between the origin and the outlets at the bar?


  • 0
    I'd have to check on what we do for live testing - if it is a bypass dimmer (physical switch to bypass the dimming circuitry) or a switchpack (effectively a relay) then this would allow live testing to the end of the circuit with the equipment  'active' but not really in the way on the circuits being tested.
  • Former Community Member
    0 Former Community Member
    jbrameld:

    I'd have to check on what we do for live testing - if it is a bypass dimmer (physical switch to bypass the dimming circuitry) or a switchpack (effectively a relay) then this would allow live testing to the end of the circuit with the equipment  'active' but not really in the way on the circuits being tested.


    Thanks for the reply, whether the (expensive?) dimmer is in bypass mode or dimmer mode, the cables between it and the IWB are not subject to BS 7671, and any, BS7671 certification, whilst well meaning in the spirit of the regulations would not be appropriate.


    The dimmer is an appliance.


     


  • 0
    Weirdbeard:
    jbrameld:

    I'd have to check on what we do for live testing - if it is a bypass dimmer (physical switch to bypass the dimming circuitry) or a switchpack (effectively a relay) then this would allow live testing to the end of the circuit with the equipment  'active' but not really in the way on the circuits being tested.


    Thanks for the reply, whether the (expensive?) dimmer is in bypass mode or dimmer mode, the cables between it and the IWB are not subject to BS 7671, and any, BS7671 certification, whilst well meaning in the spirit of the regulations would not be appropriate.


    The dimmer is an appliance.


     




    Excellent ... SmartHome installation I guess we could soon limit the extent of the installation to a control box a short distance from the CU, and all of the other building internal wiring doesn't matter?


    Not really true - in this type of installation the dimmer is really a type of switchgear or controlgear. The wiring is often fixed to a point downstream of the dimmer (or should be) ...


  • Former Community Member
    0 Former Community Member
    gkenyon:
    Weirdbeard:
    jbrameld:

    I'd have to check on what we do for live testing - if it is a bypass dimmer (physical switch to bypass the dimming circuitry) or a switchpack (effectively a relay) then this would allow live testing to the end of the circuit with the equipment  'active' but not really in the way on the circuits being tested.


    Thanks for the reply, whether the (expensive?) dimmer is in bypass mode or dimmer mode, the cables between it and the IWB are not subject to BS 7671, and any, BS7671 certification, whilst well meaning in the spirit of the regulations would not be appropriate.


    The dimmer is an appliance.


     




    Excellent ... SmartHome installation I guess we could soon limit the extent of the installation to a control box a short distance from the CU, and all of the other building internal wiring doesn't matter?


    Not really true - in this type of installation the dimmer is really a type of switchgear or controlgear. The wiring is often fixed to a point downstream of the dimmer (or should be) ...




    Hi Gk, how are domestic smart homes relevant to the Op? 


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