Downlights in a stone ceiling??

[Nijinski001]

Okay guys here's one that doesn't come around very often I bet.

A customer has just asked me to core drill a Yorkshire stone vaulted ceiling in a converted cellar to put in downlights.

My first thoughts are -
What a pig of a job to core drill holes deep enough, especially if it is LV and needs transformers.
The stone will have to be core drilled and then chipped out.
More importantly................
Where does the heat go?
If the heat can't escape there is a danger of fittings and cable melting.
If melting occurrs then fire and electrocution danger.
Even if it doesn't melt the ceiling is so low it is likely to be hot and dangerous to touch.

Can anyone else think of any other reasons why it shouldn't be done?

Alternatively has anyone done it and if so how?

Cheers

 

[andy]

and where are you gonna wire if from even if you drill the holes?

personally, i wouldnt do it. mainly because i aint got a core drill or anything.

the heat will have nowhere to go. tell them its a fire risk (at least you wont need fire hoods on them! )

only other way would be to have a false ceiling

 

[Nijinski001]

Thanks andy

They haev the idea that we will run the cables along the stone pointing and a sort angle grinder cut out to the edge of the light and a small groove up the core cut out to the back of the light.

As you said. The best fire hood I've ever seen!!

 

[ban-all-sheds]

Can anyone else think of any other reasons why it shouldn't be done?

Yes - the way that vaulted ceilings work, structurally, and how they might stop working, structurally, if you cut bits of them away.

If you're looking for a plausible way out without upsetting the customer, or losing face, say that they'll need to get a structural engineer to look at the ceiling and work out if/how/where holes can be safely cut. Will add several hundred to the price of the job, and who knows, it might even be true.

BTW - the heat problem is easily solved by using CFL lamps...

 

[Nijinski001]

Thanks Ban.
I have to say the structure was one of my initial concerns especially bearing mind 16th Ed Part A and all that.

I'm going to have a read about CFL. I've never used them.

 

[pdcelec]

I have to say the structure was one of my initial concerns especially bearing mind 16th Ed Part A and all that.

What is 16th Ed Part A?. Can find no reference to this this anywhere in my regs book.

 

[baldelectrician]

Get a suspended ceiling put in below orig ceiling, or walk away.

 

[kendor]

If you are worried about taking any responsibility in drilling the holes get the owner to hire one of the numerous specialist core drilling firms to cut the holes first. heat shouldn't be a problem as it will probably be disappated with conduction through the cold stonework. mention to the owner to get enough depth cut to allow a sufficient airgap.

 

[Nijinski001]

Thanks guys. I think I have enough to discourage him now. Obviously no-one seems to have already done this.

pdc - It was getting late and I was tired. I was referring to a hybrid of regs, some of the 16th edition wiring regs (considerations to fire risk and all the other things we have mentioned) combined with part A of the building regs (consideration for the building structure!)

I'm seeing him this morning so if there is any further progress I'll let you guys know.

 

[Qedelec]

Fit LED lights, they are maintenance free low voltage and cold running.
There are a number on the market that fit into the block pavers for drives.
They also fit into smaller holes so are unlikely to compromise the structure.

 

[ban-all-sheds]

But they don't actually illuminate anything. A nice glow to mark out the edges of a path, or steps or whatever, but they won't light up a cellar.

I'd start looking at small discharge uplighters/wallwashers as a possibility...