Home DIY

Ensuite's a wet room, or with shower? If so, and for that size of space, it'd be classed as a zone 0 special location and the fittings will have to be IP65.

Find out the coefficient of heat transmission constant for the surrounding surfaces and use the most onerous one. Find out the max operating temperature of the light fttings. A quick calc on volume and heat absorption will show if the space is adequate for the heat output generated by the lights.

Dimmers in bathrooms, hmm, local building control might get sniffy.

And one question: who's certifying the electrical installation?

It's not a wet room, it's a long thin room containing a 1m X 0.8m shower, a wash basin and dunny.

The luminaires are all IP65, and the transformers are SELV units.

Surrounding surfaces are plasterboard (which the lights will be sited in), plastered cinder block (walls), and the slightly unknown quantity- the cardboard covered concrete (ceiling).

Void space would be 0.8 X 3 X 0.1 = 0.24m.

I'll have a look at the luminaires operating temp.

Certification- erm.

Fucksticks, open the package: minimum ceiling void height 140mm.

Thanks, Screwfix.

No manual/instructions available until after purchase, somewhat annoyingly.

I might just drop the ceiling another 50mm.

Ok, so the fittings are appropriate for installation environment.

Find the W/m2.k for chipboard.

Look up online what the formula is for passive heat absorption.

The answer will indicate whether the existing volume is large enough.

Dependent on limiting temperature you may need to use high temperature cable.

Selection of a dimmer unit will need to take into account maximum load, 8 x 50 w. tbh 4 x 50w would be adequate for this space. Look around, you may be able to get a unit with a switched bypass for a fixed load.

How about using dimmable led bulbs instead?

My thinking is as follows:

If I perform those calculations and install the spots I'm still going to worry- I cannot see inside the ceiling void, so will imagine the cardboard beginning to char, and eventually flashing into flames.

So- dropping the ceiling another 50mm gives me peace of mind.

Dimmer- if that could be an issue then fine, plain switch it is.

Number of lights- yeah, I think that's a lot, however I want them to run down either side of the room rather than being centrally placed, so they shines down the wall as it were, rather than (for example) shine down centrally and therefore put you into shadow if you lean forward to check if you shaved closely enough behind the corner of your jaw.

If I was to install downlights anywhere I'd definitely use fire retardant downlight covers. I've read about the risk of heat from dowlights igniting the dust that builds up in lowered ceilings - in a ka-boom sort of way.

Led's......lots less heat.

And they last longer......

Very cold light though, which I don't like

Very cold light though, which I don't like

You can get all sorts of LEDs some warmer than others.
Try the excellently named;
http://www.mr-resistor.co.uk/

What sort of temperature do LED's typically run at?

If they are much cooler then the ceiling can stay where it is, which is of course much easier.

If you have a convenient storage area for the light box, fibre optic runs are excellent for bathrooms, wet rooms and the like. No heat to speak of at the fitting, and no electricity so can be used underwater in baths and shizzle

I could do that, as it happens, as I have purposefully built a storage area in.

However, how does it compare in terms of price to either conventional halogen spots, or possibly LED spots?

why would you want to illuminate your shizzle?

My shizzle is self illuminating, which is handy for those 4am ablutions when you don't want to blind yourself with Galvanic Illumination.

I could do that, as it happens, as I have purposefully built a storage area in.

However, how does it compare in terms of price to either conventional halogen spots, or possibly LED spots?

Not too bad IIRC, and a single halogen bulb in the light box runs a plethora of terminals.
So you only have to replace that single bulb when it dies, and not start pulling out light fittings to get at bulbs.

And, you only need electricity at the box. No runs to the fittings, save you a lot of hassle when you have to get certified.

The safety aspect, low heat and certification benefits all sound good.

I am currently only finding stuff that I'd call "spendy" so far though:

Large Fibre Optic Downlight Lighting Kit: Amazon.co.uk: Lighting

Keep looking, it doesn't have to be £500

I'll have a further look tomorrow, time for bed now.

Hope to God there will be a break in the rain tomorrow!

I have done a bit of rsearch on this & LED's are my choice, they run at lower temperatures so less likely to burn your house down (I know of at least one serious house fire, caused by halogen down lighters).

Also my architect mate recommends them for the above reason & the bulbs last longer

Ps Bemco in Wandsworth are v reasonably priced
http://www.bemco.co.uk/products34/lighting43.html

Currently searching with little joy on the relative temperatures at which bulbs run at.

There are puff pieces like this, but nothing independent that I can find.

This is a good article

This is an example of exactly the kind of bulb that my light fittings are designed for.

It is a 50W input, and 820 Candela/Lumens output (although the conversion is slightly opaque).

Whereas this LED version has an input of 1.5W and an output of 20.7 Lumen.

If this is directly comparable then I'd need 820/20.7=39.61 LED bulbs to output the same amount of light as the Halogen bulb.

Hmm.

These perhaps