Installing Downlights?

[whazza22]

Can anyone give some advice on installing downlights please.

Once all the holes are cut, do you lift floor boards above so you can get cables through joists?

 

[Jay Sparks]

Yeah, the easiest way is to lift the floor boards up. there may already be holes in the joists that other cables are going through, if there is enough space you can use them but be carefull of how many you put through a hole (grouping factor). If you have to cut your own the regs say use this formula: Max diameter of hole should be 0.25 x joist depth. Holes on centre line in a zone between 0.25 and 0.4 x span. Basically you should be able to drill a 20mm hole through the centre of the joist, this will fit a few 1.5mm cables.

hope this help mate.

What power are the lights? 12v or 230v?

 

[whazza22]

Cheers mate.

They are 230v IP20 rated. Do they need a fire guard or protection?

 

[Jay Sparks]

Pull up the floor boards is the best way. The 17th edition regs say the hole must be a max diameter of 0.25 x joist depth, Holes on centre line in a zone between 0.25 and 0.4 x span, Holes in the same joist should be at least 3 diameters apart. Basically cut a 15 to 20mm hole in the centre of the joist or use holes that are already there. What voltage are the lights 12v or 230v? and where are you putting them?

 

[whazza22]

230v to go on kitchen

Do they need fire protection?

 

[Jay Sparks]

Where are you putting them? Is the ceilling plasterboard?

 

[jjjinx]

I wouldn't use previous holes or notches made at the top or the bottoms of beams, only ones in the centre as the guys said above

 

[Jay Sparks]

If there in the kitchen you need to part p them. Which means you need to notify the building regs guys.

 

[jjjinx]

oh and your d/lighers have to be fire rated, sound rated & moisture rated as well from what I can remember. can anyone else refresh my memory on that?

when they're being put in the bedrooms where they're be in the loft area, you'll need to cut back the insulation & boards surrounding them and keep them away from joists, like 100mm from the centre of your d/ligher (depending on the size of the d/lighter).

 

[EasT]

I wondered about that. Are they in the kitchen or in the loft? or floor void?

 

[whazza22]

Kitchen

 

[Spudnik]

You do not HAVE to install fire rated spots if they are going below a room of the same house (compartment).

The only time you do need to use them is if you are breaking the barrier between compartments (integral garage or flats above).

ALL SELV down lights are notifiable, whatever room they are in.

 

[whazza22]

Thanks, is there a section in regs regarding downlights?

 

[Sintra]

Think the only regs that apply specifically to SELV lights are 559.11 although there could be more.

 

[whazza22]

Cheers.

Can IP20 rated downlights go in kitchen? (doesnt have a symbol to say fire rated)

ALso, if they are double insulated would you still take an earth or just use 2 core?

 

[jjjinx]

http://www.esc.org.uk/pdfs/business-and-community/electrical-industry/BPG5_08.pdf

Table 1 page 9

check this out for best practice, thermal effects was the third rating I was thinking about not specifically fire rating.

It would seem though that all new builds are required to have fire rated d/lighters. Building inspectors have been known to request the replacement of non fire rated d/lighters (just installed) and it is probably going to become standard in the future as when you make holes in the ceilings you are reducing the fire rating of any ceiling.

I don't disagree with what Jason is saying but it would seem to be that fire rated d/lighters would become the standard in the future.

apparently the NICEIC are trying to clear this issue up.

 

[Spudnik]

I did forget to add that i do fit fire rated as standard anyway

 

[jjjinx]

I always take an earth to the d/lighter in case they get changed, I think there might be something in the regs

Most come with a block connector for u to terminate the earth to