halogen downlighters

[simon beer]

Hi all, how easy is it to install halogen downlighters in an old lathe & plaster ceiling? The wiring is not a problem, I can sort that, just a few things that cross my mind when I think about them.

1. once I cut a hole for them the wood lathes will be unsupported, what to do here?
2. will the old ceiling be to thick for them to sit in, I think they fix using metal spring clip things.I fitted some eyeball lights in our last house but this had plaster board ceiling.

Any other points to watch out for?

Also what are the advantages or disadvantages in fitting mains powered as opposed to low voltage ones. These are to be fitted in the kitchen. Many thanks

[Roger Mills]

I wouldn't rate your chances of cutting neat holes in a lathe and plaster ceiling - although others claim to have done it ok. There was a thread on this a little while ago - a Google search might find it.

With regard to mains vs LV, there are two camps - with those in each camp tending to have strong views about it.

I personally prefer LV - because you get more visible light per unit of energy input and the bulbs last longer. The downside is that you need separate transformers - and the cables between the transformers and the lamps need to be short and fat - because they carry much higher currents, and you can't afford any appreciable voltage drop.

Roger

[Jonathan Pearson]

I've managed to do this in our ceiling, but its not straight forward mainly because when cutting a hole with a jigsaw the wooden lathes vibrate causing a larger hole than originally required, hence if you go down this route start with a much smaller hole and work outwards slowly - hand tools may be better.

The job is very dusty and dirty - may be a good idea to send the wife out for the day!!

The lights get very hot, hence you need enough (usually around 6 in) clearance above them.

If you have no restrictions then go with mains ones as they dont require a transformer (you have to hide a transformer away and they can fail after time), the 12 volt type can also be a pain as the wires which connect the lights between each other and the transformer are usually quite short which can be quite restrictive. Having said this mains ones seen to be less common, hence if you have a supplier great, if not then I managed the eventually find some at our local argos superstore.

Have fun Jon

[John Armstrong]

Depending on the fitting, there might also be a problem fixing them too. If the fitting has a clip expecting a plasterboard thickness of board, they may not be able to cope with the thickness of the _lath_ and plaster (a lathe is a big heavy thing for wood turning).

Something that might help the vibration problem is to plaster the top of the ceiling around the cutting position before starting. Once set, this should help hold it all together. Diluted PVA beforehand should help stick the laths to the existing plaster too.

The other option is to cut out an area of ceiling and plasterboard it.

[Tim Mitchell]

In article , Jonathan Pearson writes

A hole saw in a variable speed drill worked for me, go at it as slowly as possible. Not much vibration. If you get the right size hole saw, the spring clips against the sides of the hole should hold the fitting up, even if the plaster is too thick for the springs to open out.

[Steve]

We have both types in our new kitchen. I wish I'd gone for low-voltage ones all round, as they have a much nicer light quality - sort of whiter, more twinkly and modern looking. The mains voltage ones have a yellowish light, rather like a tungsten bulb.

[usenet]

Er, they *are* tungsten bulbs! :-)

[simon beer]

Maybe that is why the ceilings are so thick! thanks for replies

[Tim..]

I recently fitted 30 12v eyeball downlighters in 2 new bedrooms and landing in an attic conversion. It was lath and plaster which we ripped down to create more ceiling space by moving the joists upwards. Then plaster boarded and plastered. Hole saw to cut the holes.

Anyways, I went for 12v cos bulbs are cheaper and last longer and more efficient- despite losses in the transformer. Situated the transformers centrally in the room (where the original ceiling rose was) and ran radial

1.0mm 2core PVC to each light position from a 30a junction box at each transformer. Min lenght was about 30cm and max about 3meters. All rooms have dimmes which ensure a soft start. Despite the different cabling lengths all lamps run at the same brightness, and look damn good!

My 2p..

Tim..

[Roger Mills]

The reason for the 12v lamps being whiter is that they run at a higher temperature. Because they carry a high current at low voltage, the filament resistance is very low - so the filament is very short and fat compared with a long and thin one in mains lamps. This, in turn, means that it is physically much stronger and can run much hotter without failing. As any schoolboy will tell you, the wavelength of light emitted is inversely proportional to the temperature. Thus a higher temperature means that much more of the radiation emitted is in the visible part of the spectrum rather than down in the infra-red. This means more visible light (and less heat) per watt of input power *and* the light emitted is whiter.

Roger