Using 72mm pipe as downlight boxes

[joshthejew]

Hey guys.

I have an engineer that wants the downlights in a concrete roof using a large diameter pipe as the D/L box as to not skim the concrete ceiling.

Now i have specifically stayed away from that type of practice my whole career. But i see some contractors have done it. And their justification is that the pipe is the "acting" junction box for the downlight and terminations.

Any insight will be much appreciated.

Cheers

[GCE]

Hi
We flatly refuse to use a pipe for the down lighters
The down lighter clipping mechanism does not allow to hold the down lighter in place , it needs a flat surface for the springs to clip in the "ceiling space" - and also not to thick - We have seen down lighters bend from the heat when they are installed in a 32mm board
The engineer will want you to glue the fittings into place and when they start coming loose it will be at your cost to make a plan at a later date .

A pipe is not classed as an enclosure and has no SABS standard to be allowed to be used as such - You sign the coc and state that all "components have been correctly installed".
In Sans 10142 - 5.1 note 2 - The manufacturers instruction may contain more stringent requirements - I doubt the down lighter manufacture will allow it .

There is the question of heat, which the pipe may not allow sufficient air space and when the lamps start failing you will be told that there is a heat build up - Again , the repair and making a plan to get rid of the heat will become your problem at your cost further down the line.
They all forget that if you do don't have sufficient airspace around an LED lamp you will overheat and have a short lamp life.

Depending on the down lighter been used you can also use 7.9.3.3.1.2 onward to argue against it.

If after all the arguing you still look like you are losing the battle , let the engineer give you a written instruction with the installation method , fixing method etc and make sure he states that he , as the designing of the installation takes full responsibility for any latent defects that may appear down the line.

Attached that letter to your COC and ensure that he signs section 5.1 of the COC.

If the engineer is not an Electrical engineer then he cannot take responsibility - I am assuming it is a structural engineer - I would be surprised if an Electrical engineer asked you to use a pipe

[AndyD]

If it's halogen downlights then I'd say definately not.

I'm not sold on the idea of a plain pipe type for many of the reasons stated by GCE but there are products on the market that are suitable for unskimmed concrete ceilings (also here), they're not available in SA as far as I know but I'm sure you can possibly mail order or fabricate something similar yourself.

[SilverNodashi]

Does LED downlights produce the same mount of heat as the old type?

[Justloadit]

It should not, however the down lighters require air flow to ensure that the LED element does not exceed 70Degrees centigrade. After this point the LED element starts to degrade pretty fast, and will become dimmer and dimmer and eventually fail prematurely.

Unfortunately, to maintain a low price, the LED down lighter manufacturers are reducing the size of the heat sink, to save costs. This of course has a direct effect on the temperature that the LED elements experience during their lifespan.

Note that when an LED lamp is rated in watts, it effectively states the amount of energy that it consumes as a load, which is a direct link to the temperature that the LED will emit when in operation. It is important to get the heat away to ensure longevity of the LED light.

[Justaquestion]

Installing downlights on a concrete ceiling

Hi there, i apologise if this question has been asked before. New to the forum and cannot locate any info.

Please can someone let me know if its possible to add downlights to a concrete ceiling. or what other options are available. I looked at lowering ceilings and bulkheads but its a bit too expensive for me at the moment.

thanks

[GCE]

Hi

It will basically be the only way is a ceiling or bulkhead - You would also need space to wire within .

There are surface down lighters that you could fit and with LED now they are reasonable thin , talking 30mm if memory serves me correctly - you would also then have surface wiring