Recessed lights - connections and clearance

Discussion in 'Electricians' Talk' started by tasty fish, Oct 27, 2003.

  1. tasty fish

    tasty fish Member

    I've just bought several sets of Low Voltage Halogen downlight kits. I want to place one lamp where there is an existing light fitting, connected to a ceiling rose. Do I connect the Earth and Neutral from the transformer to the ceiling rose (as you would for a standard light fitting) and then push this into the space above the ceiling? Is this safe? Or, do I remove the ceiling rose and wire the transformer up to a new junction box that also accepts the switch cable and 2 mains circuit cables?

    I reckon I'd have to cut a slot and push the ceiling rose through this into the gap otherwise the hole will be too big for the recessed light. Would that be correct?

    And finally, how far should any insulation be from the lamps and transformer? I read somewhere that I might need a fire shroud! Any advice would be much appreciated. The instructions on these things always assume you can lift up floorboards, etc (I have chipboard under my floors!) and that you have fantastic access to the gaps beween ceiling and floor!

    Cheers.
     
  2. tasty fish

    tasty fish Member

    oops, I meant "Live and Neutral" not "Earth and Neutral" (the brown and blue ones)
     
  3. supersparky

    supersparky New Member

    a cieling rose will do the same job its just good practice to change over to a j box (u do have to remove the pandantand wire the transformer into it)
    and as for going through ytthe cieling i usually cut the size of the light out and then cut 'ears' on either side so the jn box will fit through as this wat it can be rapaired easily
    and as for the fire shroud, ive never seen or fitted one my self on domestic installations
    as for the insulation diatance if it is boarded over the top push it back as far as you possibly can if it has a space above it as in a loft i would say 15cm at minimum all round but make sure it wont fall back onto the light
     
  4. tasty fish

    tasty fish Member

    Cheers Supersparky, much appreciated. I'll try the J/Box as atleast you can cover them. I've cut the insulation out around the lights back by about 20cms.

    One last question: If I use a J/Box can I connect the 2 mains cables, the switch cable, and the cable from the transformer all into that one J/Box, or would I have to lead a spur off a new J/box on the mains circuit to another J/box where I connect the transformer and switch?
     
  5. supersparky

    supersparky New Member

    you could connect it all into one but by my own personal preferance i always run it into its own j box if i can but, when you say kit i asssume you have one transformer for 3 lights or so? if you only have one transformer it won't make much difference how you do it but if you have a few trannys to come off this switch then it will make your life easyer to have multiple jn boxes (one at each light and ****** position)
     
  6. tasty fish

    tasty fish Member

    many thanks once again - will try the one J/Box fits all method! Yes, it is a kit: one ****** + 3 lights, with simple pushfit connections.
     
  7. supersparky

    supersparky New Member

    ok good luck, glad to be a help
     
  8. chtechie

    chtechie Member

    You'll find the standard 5A (18802)junc boxes fit through most downlighter cutouts without needing to cut 'wings' and although it's a bit tight you can get 4 x 1mm T&E and the transformer cable in and be neat.

    You mentioned heat shrouds - I asked tech support of 'Aurora' who make a lot of Screwfix downlighters this question and they said 'Fire hoods, as we sell them, are only required to be installed in ceilings which are deemed to have a fire rating, this means the ceiling can withstand fire for certain amount of time.
    A ceiling may be deemed to be fire rated if it is stated so by the building regulations, architect or builders. The theory is that if you cut a hole in a fire rated ceiling you have to maintain the fire rating of the ceiling by installing fire hoods.

    As a quick visual guide, if the ceiling has double thickness plaster board, that can usually mean that it is fire rated. If you are unsure contact your local building authority for more information.'

    Sec 42 of the regs gives all the info on protection against thermal effects - My interpretation is that if you consider the proposed installation will generate heat which will cause a risk then you must either 'mount it at a safe distance' or 'screen it' so your only other option is to reduce the heat (therfore reduce lamp wattage) which will decrease the clearance required.

    Hope this helps - Regards, David.
     
  9. supersparky

    supersparky New Member

    i see my mestake ther what i ment to say was you may need to cut wings if you wst the ceiling rose and as for the fire chack on the ceiling, only need to be aware of that in donestic terms if its a conversion i.e 1 house change to two flats
     
  10. supersparky

    supersparky New Member

    and chtechie your not a sparks are you? i install alot of low voltage lights on a regular basis,
    also dobbling back on what i said earlyer, i doubt you will use a 5 amp junction box as in my opinion anyone will find it hard to acomodate the cables in such a small jn box, i would personaly use a 20amp 4 terminal as there is easly enough space, unlike the 5 amp which is only good for looping each transformer into, on a multiple prensformer system, in this instance it is not the case as there is only one ****** so there will be no need for a 5amp jn to be used
     
  11. chtechie

    chtechie Member

    Think we're just talking at slight cross purposes - Only meant it is possible - As you rightly say a 20A is much more accommodating when you're dealing with several cables.
     
  12. supersparky

    supersparky New Member

    fair enuf then
     

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