Spotlight clearances

[mgsinx]

I have installed a set of LV Halogens, which look stunning. They are running off a soft start dimmer which is great. Though i have two questions...

1 - some of the holes in the celing come close to the joists. Does anyone have any good ideas about something that i can use to prevent the joist from heating and potentially igniting. Or am i being too overcautious here? I have heard some people use terracotta flowerpots - is this really viable?

2 - the time it take for the lights to come on from cold can sometime be 5 secs. I have checked the rating on the dimmer and it all appears in order. Is this something to do with the transformers kicking in?

Tom.

 

[Steve]

You probably have soft start dimmers on soft start transformers, which will multiply each other's soft start effects!!!! But its nothing to worry about, as long as neither gets too hot during use (warm is ok, hot isn't)

Your joists wont overheat or ignite. Teracotta pots can be used if you like, they are ideal for re-laying insulation around downlighters, as there is a hole to let the heat out and you're not loosing as much insulation.

 

[mgsinx]

thanks mate, thats reassuring. I think i will go with the teracotta Pot idea, though it seems slightly cowboy if it works with the insulation who cares!

 

[Big_Spark]

I wouldn't use terracotta pots, they absorb heat and can get a lot hotter than the fitting they protect..(UNLESS you line them with tin foil to reflect the heat)

Proper hoods are the best bet.

 

[Steve]

Proper hoods are the best bet.

down with fire hoods!

They dont let any heat out, and will also get very hot, possibly hotter than the terracotta pots!

 

[mgsinx]

Yes, i have heard that fire hoods are not any good and that they reduce the life of the bulbs because they cause heat retention.

If the joists are not in danger, i will leave them open i think and just cut the insulation right back

 

[RF Lighting]

How close to the joists are the fittings? and what sort and rating of lamps are you using?

I have seen a joist burned by a downlighter and dichroic lamp.

 

[mgsinx]

the closest one is 10-15mm away from the edge of the bulb, 50mm away from the centre. How close was the one you saw burned out?

They are 50w 12v bulbs.

 

[RF Lighting]

What is the minimum distance specified by the manufacturer of the fittings?

We leave a minimum of 75mm clearance from joists where I work.

 

[mgsinx]

The manuf reccommends "50mm or appropriate consideration be made to prevent fire". As i have had to install them close to the joists i'm looking for some way to prevent the worst of the heat from getting to the wood.

There must be some kind of heat barrier i can fix to the side of the joists?? Was thinking of a ceramic tile?