Low voltage wire/cable suspended lighting

[Nick]

Hello. I'm wanting to illuminate a large dark gloomy old room. 17th century, low ceiling with exposed beams. Very little natural light. I am thinking that something like this

be suspended between the beams and be almost invisible when in use.

I know little of the subject and would much appreciate any pointers or comments. The items in the above link seem somewhat expensive for the area I would like to illuminate. Would require probably 4 runs with 3 or 4 lamps on each run when combined with wall lights and other free standing lighting. Also, could the transformers be hidden tween ceiling/upstairs floor (6"/150mm gap) and would this present any fire hazard?

I presume I could use 6mm stranded steel cable with proprietory lamps and fixings. How do I calculate the size and type of transformer required. Line lengths can easily be calculated. The number of lamps & wattage etc. is not so simple Sorry, this is very vague and I am literally stabbing in the dark. Any pertinent comments would be much appreciated.

Thank you,

Nick.

[BigWallop]

For cheaper prices, try here

are nice in situations as you have described, but remember the head room on low ceilings. These lamps get hot.

There are decorative transformers that fix to the sides of the beams and don't spoil the look of the room. If you wish to hide the power supplies in the voids, there should be no problem, but a word of warning again is, these do get hot and are not suited to very tight spaces or places filled with insulating materials. They do need some ventilation to prevent overheating.

It is best to go with the largest power supply you can get. This gives the option to add or subtract lamps as and when needed. The calculation is simply Power Supply Wattage divided by the Wattage of the lamps you want to use. Example: 3 x 50W lamps needs a 150W transformer. Simple as that.

The link I have supplied to Mr Resistor will take you to the section on this type lighting product. They supply everything needed to complete the project, Transformers, lamp holders, tension wiring and spacers etc. I think they can even supply the fixing screws, but don't hold me to that. :-)

Have a look through the site and I'm sure you'll find it helpful. Have fun with it all.

[dom]

I was looking at their DimSlim dimmable fluorescent range the other day - expensive, but exactly meets my needs.

[meow2222]

It would be highly visible and very out of character. Traditional twin wall fittings are more in keeping with such houses. They can take filament lamps or CFL, as you wish.

yes

yes - in which case get standard low cost transformers rather than their prettified expensive ones. Fire hazard, yes inevitably.

Just add up the wattages of the lights you'll run off it. As said, when you dont know what power lighting you want, pick higher power to give you room to play.

Probably easiest way to get a ballpark idea is to use a couple of portable lamps, fit whatever bulb wattage is required to get enough light, then you've gota figure to start form if using halogen or filament. Divide by 4 for CFL, or 5 for linear fl.

NT

[Dave Plowman (News)]

All the transformers I've seen are as fireproof as any such thing.

I've got something similar in my conservatory which came as a kit from one of the sheds. The cable is copper - not steel - as it doubles as the conductors. The fittings are specials as their supports need to pierce the insulation.

Transformers are usually specified in VA. For a resistive load like a lamp this is the same as watts - so just add the wattage of the lamps together. But with low voltage lamps you also have to worry about the cable losses.

Here is a calculator:-

[BigWallop]

They supply all the lighting materials, and advice, for all those types of jobs we do. Yes. I would recommend them without hesitation.

Their prices are actually very reasonable, because the quality of their stock is not rubbish, and they will advise on things you are not sure about.

[Calvin]

Ouch, those are expensive. QVS

do wire lighting (they call it "wire rope" lighting) from =A335 plus VAT for the very basic set. I have a 5-lamp set in a bedroom with a vaulted ceiling and they're really great. For some reason that I don't really understand most wire light kits come with a proper magnetic transformer. Personally I'd prefer to use a much smaller switched mode supply and hide it away, which is exactly what I'll be doing when I fit the same thing in my hallway early next year.

Four runs with 3 or 4 lamps on each is a minimum of 4 * 3 * 20W =3D 240W of lighting which is quite a lot. I've not seen your room but I suspect you might find that a little overpowering. Maybe you could consider fitting less lamps to each run. Remember that you can cross- link the runs so that two or more physical runs are one electrical circuit IYSWIM. Depending on your particular situaltion you might be able to buy less than 4 kits and a couple of odd bits like coupling clips and so end up with say two power supplies driving two runs each and say half a dozen lights spread between them.

Good luck with whatever you end up doing.

[meow2222]

re halogen lights suspended on cables

That raises another point: suspended lights may be on long wire runs, and that is a problem for some electronic transformers, the heavy iron ones will always work on long runs.

NT

[Calvin]

Really, why's that then? It can't be capacitance as the wires, although parallel, are not close together. In practice the wire run for wire lights is typically only about 5m or so which might sound long but isn't really compared to normal cable runs.

[Andy Wade]

Series inductance - if the 'transformer' has a high frequency AC output the voltage drop due to the inductive reactance in the circuit can be very significant in the context of 12 V lighting.

Here's a previous thread on the subject:

[Dave Plowman (News)]

I'd hope it hasn't - radiating RFI is surely controlled by regs?

[meow2222]

and naturally all cheap chinese goods comply with all regs.

NT

[Huge]

The EMC regs are rubbish, anyway.