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LED 240V Downlight comes pre-terminated with unsheathed cables

NigelS
I recently installed some Luxna GU10 Fire Rated downlights as part of a bungalow refurb. The lights are installed into a ceiling that has the loft space directly above.


Before completing the installation certificate I had a check through the installation and I suddenly noted something about light fittings in question.


The light fitting comes with an L bracket attached with a small termination box attached to the bracket.  The live and neutral wires then come pre-wired out of the case with a sheath around, however, the sheath is cut short and so the wires enter the termination box un-sheathed. This is all part of the light fitting. They are three of these same fittings and they are all wired the same way.


Obviously, I have brought my cable into the other side of the termination box ensuring that it enters the box sheathed, as per BS7671 reg 526.8 which states that no basic insulation should be visible outside an enclosure.


However, I don't see how I can say this installation meets the requirements of BS7671 when this downlight has unsheathed cables entering enclosure even if it part of the pre-wired fitting.


I queried this with the manufacturer through my wholesaler and they said the following:

"The IEE Wiring regulations relate to the electrical installation itself rather than the individual products used.

Our understanding of Chapter 526 is that it relates to electrical connections and terminations made by the installer (so would relate to the connection of the supply cables into the terminal block) rather than any wiring within the luminaire. Whilst not relating to the luminaire, Regulation 526.8 does state that non-sheathed cables should be enclosed as required by Regulation 526.5, which states the enclosure can be “partially formed or completed with building material”. As the luminaire is recessed into the ceiling, the ceiling itself would therefore act as an enclosure.

Further to this in Chapter 559 which relates to Luminaires and Lighting Installations, Regulation 559.6.1.1 states that “at each fixed lighting point one of the following shall be used: …. (iv) A luminaire to BS EN 60598”.

The Luxna GU10 FRD downlights are certified to BS 60598-1 Luminaires – Part 1: General requirements and tests and to BS EN 60598-2-2 Luminaires Part 2-2: Recessed luminaires, and will therefore meet the requirements of Regulation 559.6.1.1."


I replied saying that, in this particular installation the fitting is in a ceiling which is into a loft space so is accessible and not enclosed and inaccessible, unlike a normal ceiling. Plus, from a pure risk assessment point of view, I see no difference between an unsheathed cable going into one side of the termination box that is wired by the installer and an unsheathed cable going into the other side of the termination box that is pre-wired by the manufacturer. Also, I do not know what requirements need to be met by manufacturers for their lights to meet BS 60598-1, but how can a cable pre-terminated in a light fitting during manufacture be to a lower level of safety to that required by the installer?


I would be very interested to hear what other members think about this, and importantly can I say the installation meets the requirements of BS7671 even with this light fitting pre-wire the way it is?


Cheers to anyone who has bothered to read this.


Regards


Nigel
  • 0
    In the past  have had similar questions about wall lights, and relying on the wall as half the enclosure for single insulated cables, and a very non-flat wall.

    I think the answer 'it is part of the product, not the wiring so is outside BS7671' may well be legally watertight, and there will be no trouble in practice, but I suggest it leaves a nasty taste.

    Now if they had said that was special wire and has re-inforced insulation, so is in effect double insulated, or if they provided any means at all to cover it, we would both feel happier.

    Many product standards allow things that BS7671 would not (the obvious one being lamp holders you can put fingers into) and even BS 7671 allows singles inside trunking with finger sized holes in it (IP X 4 comes to mind) but this is not really quite like that.

    I think it is OK, in the sense you are covered by the maker's explanation, but I understand your concern.
  • 0
    Thanks, for your reply Mike.

    I am surprised BS EN 60598 allows this, and it if makes their products cheaper to manufacture then I guess its what we can expect.

    Cheers

    Nigel
  • Former Community Member
    0 Former Community Member
    downlights are certified to BS 60598-1 Luminaires – Part 1: General requirements and tests and to BS EN 60598-2-2 Luminaires Part 2-2: Recessed luminaires, and will therefore meet the requirements of Regulation 559.6.1.1."


    Certified by?


    To, as in towards, but does it actually get there?


    "Complying with" would appear to be more committal (allegedly).


    Regards


    BOD




  • 0
    Further to Mikes comment, I imagine he means IP4X which would not allow a 1mm diameter wire to penetrate although,  strangely, trunking can meet IP4X or IPXXD the latter allowing a 35mm hole through which a finger could easily pass. If the live parts are insulated then the probe, a 1mm diameter wire, can make contact with the cables within. It would seem reasonable to conclude that a 35mm hole in trunking in which there are single-insulated cables would meet 521.10.1.

    that being the case, it would be hard to be agitated about the single insulated cables on your light fitting. Nonetheless, I agree that the manufacturer didn’t need to stretch the point and could have easily designed out the issue.
  • 0
    I have come across downlighter claiming to be double insulated with exactly the same configuration. I struggle to see how they are double insulated but without trawling through standards document that cost a fortune to obtain it is difficult to determine whether or not they do correspond with a standard. I also had the same basic concern about the 1/2 inch or so unsheathed wires outside the connection box.
  • 0
    As an update, I have had an email back from the wholesaler head  office who have said:

    "we have looked into this further and the cables used on the product actually have two layers of insulation built in – the basic layer and a supplementary layer. You can see this in the example image below and attached (from the actual downlights). You will see there is a white layer of FEP material which acts as the basic insulation, with a secondary layer acting as the supplementary insulation (the brown/blue Teflon sheath).
    4fc0b824c858d58099f9b5bb0e72ef08-original-image-20200826123450-1.png

    Based on the above, I understand the cables used do comply with Regulation 526.8 as there is no basic insulation accessible, as well as meeting all of the requirements of BS EN 60598-1."


    see also attached photo below

    191701416011772438.jpg


    From the ,jpg image attached you can see how you certainly wouldn't have thought these cables were double insulated by looking at them from the outside, you would have had to cut them to check, they looked like ordinary singles to me. 

    So I will take their word that these are double insulated and leave it at that.

    Nigel
  • 0
    There are two things here. Sheathed cables are not and never have been "double insulated". The sheath is classed as mechanical protection and would be fully compliant even if conductive, as long as it was earthed. The second is that unsheathed cables are perfectly compliant for insulation, as long as they have mechanical protection. Clearly the product standard does not see the reason for mechanical protection so close to the fitting, therefore the fitting is compliant, and it does not have to meet BS7671 standards for mechanical protection.


    So the manufacturer is perfectly correct whatever you may think. I do agree it is a bit shoddy, but they were probably cheap!
  • 0
    Thanks Dave, yes, I should not have used the term "double insulation" in my last post. You're also right in assuming that they were cheap.
  • 0
    NigelS:

    Thanks Dave, yes, I should not have used the term "double insulation" in my last post. You're also right in assuming that they were cheap.


    No need to apologise really ... Regulation 412.2.4.1 (ii)(a) says that a cable, properly installed in accordance with Chapter 52, in which the insulated conductors are mechanically protected by a non-metallic sheath, are deemed to meet the requirements of double or reinforced insulation.


  • 0
    You can add the term “All-insulated” to your list.


    Andy B.

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