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Replacing single light by 5 Downlights

Discussion in 'Electrics UK' started by gillpeer, 8 Mar 2009.

  1. gillpeer

    gillpeer

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    I have a single light connected to the fan by a pull cord in my bathroom. I am thinking to replacing the single light with 5 down lights. Should the downlights be connected in a star shaped circuit with spurs going from a junction box to each light's transformer or should the cable be run from the existing light to the second light and then to the third light etc.

    A wiring diagram would be much appreciated.
     
  2. breezer

    breezer

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    from first to 2nd etc mn (there you go, from one to the next etc)

    not all require transformers and are you aware of part P
     
  3. Taylortwocities

    Taylortwocities

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  4. laughingjester

    laughingjester

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    i'd do the latter. from existing light to 2nd to 3rd etc . also use choc boxes feeds in and out into choc box, then transformer out of choc box to light . YOU MUST USE IP44/FIRE RATED DOWNLIGHTS ASWELL. :LOL:
     
  5. RF Lighting

    RF Lighting

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    Why?
     
  6. Taylortwocities

    Taylortwocities

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    IP44 maybe a requirement depending on positioning. Also IP44 will reduce amount of steamy moisture being sucked into the roof void.

    But why fire-rated :?:
     
  7. ban-all-sheds

    ban-all-sheds

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    An IP44 luminaire may well reduce the amount of warm moist air entering the roof space, but it won't eliminate it, and therefore won't provide a way to comply with Part C.

    gillpeer - your plan has a number of serious flaws.

    Firstly, this is notifiable work - see http://www.diynot.com/wiki/electrics:part-p, and I'm not trying to belittle you, but quite honestly if you need a wiring diagram to install a few lights you probably aren't truly competent enough to be doing it.


    Secondly, since it's notifiable, there's no way you're going to be able to get Building Regulations contraventions past the BCO. It isn't just Part P that you have to comply with, it's all of the relevant regulations, and Parts C & L are immediately obvious hurdles.

    If you've got a roof space over the bathroom then you will have to completely seal around the lights as you must prevent warm moist air from entering the unconditioned space because if you don't you'll get condensation up there - a contravention of Part C.

    Part L problems are twofold - if there's insulation in the loft then you cannot remove it, because if you do that will make the degree of insulation worse than it was before, i.e. your degree of compliance with Part L will be less satisfactory than it was before. But you can't leave the insulation in place because the lights will require a clearance all around them to avoid overheating, so you'll need to install some kind of structure around the lights to provide clearance and to allow the insulation to be maintained.

    See these for details of keeping insulation, providing space around the lights and sealing against moisture:

    http://www.nhbc.co.uk/NHBCPublicati...ical/StandardsExtra/filedownload,16553,en.pdf

    Pre-formed cap to seal downlights: http://www.aico.co.uk/firecap_loftcap.htm (It's NOT a firehood....)

    The second Part L issue will be the efficiency of the lights. Since you mention transformers I'm assuming the lights you plan to install use 12V halogen lamps. These will not be efficient enough - even though the Building Regulations don't actually mandate luminaires which cannot take incandescent lamps that is what Approved Document L says you have to use for a certain percentage of your lights, and rightly or wrongly many councils regard that as mandatory, so you could have a real struggle to get ELV halogens passed.


    Finally the whole thing is crazy anyway. What is the wattage of the light you're removing?

    How much greater is the combined wattage of the ones you plan to replace it with?

    How sensible is it to deliberately make your lighting significantly less effective than it was before thus requiring a large increase in the amount you have to have in order to light the room as effectively as it was before?

    (Hint - it isn't sensible at all).

    Don't do it.
     
  8. Steve

    Steve

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    I used to have a single 60w globe luminaire in my bathroom. I now have three 9 watt downlights. :D They rule. :p
     
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  10. laughingjester

    laughingjester

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    because if your cutting say 3 x 50 -70 mm holes in your bathroom cieling ip44 fittings seales against moisture. also your damaging the fire barrier (which in this case is the cieling)so half hour fire rated downlights should really be fitted to stop the spread of fire to the loft if one should occur.
     
  11. ban-all-sheds

    ban-all-sheds

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    No they don't.


    It's been shown in tests that downlighters do not compromise a 30-minute ceiling.
     
  12. laughingjester

    laughingjester

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    yes they do...IP44 rated explained.

    It is important to understand the rating by which bathroom lights are classified. IP rating stands for 'Ingress Protection' and is always followed by 2 characters.

    These 2 numbers refer to the level of protection (from water, steam, dust) and it is important that you choose fittings with the correct rating according to where they are to be sited within the bathroom.

    how do you know his ceiling is a 30-minute one? my guess its not unless its a new build. And who are you to question part p, and also part b of building regulations on maintaining fire barriers? also where is this info on tests that have been done on downlights and 30-minute ceilings i would like to check it out. :LOL:
     
  13. laughingjester

    laughingjester

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    Technical IP Ratings

    IP Explanation and Ratings

    EN 60529 outlines an international classification system for the sealing effectiveness of enclosures of electrical equipment against the intrusion into the equipment of foreign bodies (i.e. tools, dust, fingers) and moisture. This classification system utilizes the letters "IP" ("Ingress Protection") followed by two or three digits. (A third digit is sometimes used. An "x" is used for one of the digits if there is only one class of protection; i.e. IPX4 which addresses moisture resistance only.)


    Degrees of Protection - First Digit
    The first digit of the IP code indicates the degree that persons are protected against contact with moving parts (other than smooth rotating shafts, etc.) and the degree that equipment is protected against solid foreign bodies intruding into an enclosure.

    0 No special protection
    1 Protection from a large part of the body such as a hand (but no protection from deliberate access); from solid objects greater than 50mm in diameter.
    2 Protection against fingers or other object not greater than 80mm in length and 12mm in diameter.
    3 Protection from entry by tools, wires, etc., with a diameter of thickness greater than 1.0mm.
    4 Protection from entry by solid objects with a diameter or thickness greater than 1.0mm
    5 Protection from the amount of dust that would interfere with the operation of the equipment.
    6 Dust tight.


    Degrees of Protection - Second Digit
    The second digit indicates the degree of protection of the equipment inside the enclosure against the harmful entry of various forms of moisture (e.g. dripping, spraying, submersion, etc.)

    0 No special protection
    1 Protection from dripping water.
    2 Protection from vertically dripping water.
    3 Protection from sprayed water.
    4 Protection from splashed water.
    5 Protection from water projected from a nozzle
    6 Protection against heavy seas, or powerful jets of water.
    7 Protection against immersion.
    8 Protection against complete, continuous submersion in water.

    Submersion depth and time must be specified by the end-user. The requirement must be more onerous than IP67
     
  14. flameport

    flameport

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    Equipment with a rating of IPX4 is protected from splashes of water only. It will not stop water vapour.

    Most/all of the ceilings in a normal house will not be fire barriers. The only common ones are the roof of an integral garage, or if the house has at least one floor over 4.5m from ground level (loft conversion etc.)
     
  15. laughingjester

    laughingjester

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    isnt that pretty much what ive just been saying :eek:
     
  16. Steve

    Steve

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    Erm actually . . . no it isn't!

    You said something about the age of a property having something to do with fire barriers. :confused: Nothing about its height or garages.
     
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