Discuss Downlight min distance to joists in the Lighting Forum area at ElectriciansForums.net

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Yes that one again - been answered a millions times BUT often the answer is do what the MI say. I have the Enlite DLM982x and it doesn't specify any distances. Obvisouly I'm fitting LEDs but these cans would in theory allow a halogen.

SO, belts and braces seems to suggest 50mm but could I fit them 20mm? Touching ? If not why not? - Where is the reg?
 
reg. is in the common sense guide to fitting downlights. a copy of which, bathroom fitters don't seem to possess. ( if joist is in the way, drill it out).
 
There is a Regulation about distances between luminaires and combustible surfaces.
 
There is a Regulation about distances between luminaires and combustible surfaces.
Which reg and what does it say? I couldn't see anything in my onsite guide 18th. Maybe its in part p somewhere?

As an aside, obvisouly it shouldn't be touching or even "very close". But is 40mm allowed or not ? I'm starting to think there is no rule about this which strikes me as odd. If there isn't how close do you dare to fit them under customer pressure etc..?
 
Yes that one again - been answered a millions times BUT often the answer is do what the MI say. I have the Enlite DLM982x and it doesn't specify any distances. Obvisouly I'm fitting LEDs but these cans would in theory allow a halogen.

SO, belts and braces seems to suggest 50mm but could I fit them 20mm? Touching ? If not why not? - Where is the reg?
The downlights you are fitting are ok to be covered with insulation, on the condition that only LED lamps are fitted. Check the manufacturer's instructions for exact wording and max wattage. With that in mind, I doubt a joist 20mm away would a problem if LEDs are used.

How you're supposed to prevent someone in the future changing the LEDs to halogens is anyone's guess, but you would expect the manufacturer to have considered this possibility and presumably they must be happy that it's not their problem if someone did.
 
Starting to think that if pushed, you could put something non-combustable (old tile or bit of cement board) inbetween the joist and lamp. If it can be covered in insulation then one side of it lined with a slate doesn't seem contrary?

Edit: Just to add thanks for all previous replies which have been constructive....
 
The minimum distance is often stated on the box or in the instructions. We had to fit some for a customer they supplied and they had to be 70mm from timber according to MI
 
An old question but a good one. A bit like bonding which comes up again and again causing confusion, mainly to me!

What is the actual problem with fitting a halogen light by a joist? Would the halogen eventually burn into the joist weakening it? Or, is it more based on the position of the downlight with regards a fire, i.e if there was a fire it would zoom up right by a joist (assuming it wasn't a fire rated downlight).

What would be the problem with regards an integrated, fire rated LED downlight right by a joist?
 
I've seen scorch marks from halogen downlights, when they've been positioned next to joists. Thats not a good thing.

Although LED lamps & luminaires, don't give out the same heat, they do give out some which needs to dissipate. This could lead to premature failure of the luminaire.

This report just goes to show the importance of installing fire rated luminaires whatever the location, especially with I joists.
 
What is the actual problem with fitting a halogen light by a joist? Would the halogen eventually burn into the joist weakening it? Or, is it more based on the position of the downlight with regards a fire, i.e if there was a fire it would zoom up right by a joist (assuming it wasn't a fire rated downlight).

What would be the problem with regards an integrated, fire rated LED downlight right by a joist?

Halogen lamps next to joists cause them to scorch/smoulder, this can lead to fire.

Once upon a time downlights were all open backed so if they were too close to a joist you ended up with the hot lamp almost touching the joist which led to the scorching/charring of the joists.

So manufacturers started putting minimum distances from joists on their instructions to cover themselves in the case of idiot installers.

Now we have integrated LED downlights which don't get anywhere near as hot and will be perfectly OK next to a joist, but manufacturers continue to specify minimum distances from joists because they have done for years, and they originally did it for a good reason, so why would they stop?

Rules and regulations get changed when something is found to be dangerous, they tend not to get changed back when the danger is removed, they just get left as they are.
 
Halogen lamps next to joists cause them to scorch/smoulder, this

Now we have integrated LED downlights which don't get anywhere near as hot and will be perfectly OK next to a joist, but manufacturers continue to specify minimum distances from joists because they have done for years, and they originally did it for a good reason, so why would they stop?

Rules and regulations get changed when something is found to be dangerous, they tend not to get changed back when the danger is removed, they just get left as they are.

Think you’ll manufacturer’s of sealed unit led luminaries recommend air circulation gaps around their fittings otherwise they might prematurely fail, especially solid objects like joists.
 
Just out of interest, what’s your thoughts on spotlights in wooden panelled ceilings with halogen lamps?
Also it’s easy enough to stick to manufacturers instructions regarding insulation unit a few month later, someone’s in the loft and insulation gets back over the fitting.
 
I take it you mean drill the joist to fit the light

It's a 2 year old thread, but I think Tel was joking!

Welcome to the forum by the way!
 

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