low voltage lights

Hi

As usual lookign to save a bit of time and effort....will this work??

I currently have 7 low voltage halogen spotlights in my kitchen eac with 20W bulbs. Its so dark - no real natural light - so I want t replace. Each of the lights appears to be fed by a single transforme in the celing void (which I can not see). I beleive this is the cas as each light simply has a chocolate box connector connected to th small white plug in which the bulbs two prongs sit.

Can i simply plug in 50W low voltage (MR16) bulbs in their place? Thing is, I tested the voltage at each outlet and it only seems as i

7V is coming through?

Getting to the void from the floorboards above is going to be a rea pig of a job but I dont want to overload the transformer??

-- alexbartman

Reply to
alexbartman
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I'm not sure what you mean about the number of transformers. Your wording suggests that there are 7, but your description of the wiring suggests that there is only one - with all 7 lights connected to it.

Either way, the type of transformer used for low voltage lights only works over a narrow range of power outputs. If your transformer was rated for 50w lamps it wouldn't work properly with 20w lamps. If it's rated for 20w lamps, you *certainly* can't replace them with 50w lamps.

You will also get misleading results if you try to measure the voltage of a switch-mode transformer under no load. You need to be powering the lamps, and measure the voltage across one of the lamps.

I'm afraid that you're going to have to get into the ceiling void to sort this lot out. Apart from anything else, if you're using 50w lamps you'll probably need thicker cable. A 50w lamp at 12v needs over 4 amps - compared with 0.2 amps for a mains bulb - and with only 12v to play with, you can't afford any appreciable drop in the cable between transformer and lamp.

Reply to
Set Square

I don't think you can assume that means each light has its own transformer. Your system could easily be wired with >2 cables radiating from one transformer.

You sure you can't get at the transformers more easily? They are often installed from below by being pushed up through the holes cut for the light fittings. They shouldn't be totally unaccessible, as they do die once in a while and need replacing.

I think you need to examine the transformers; there are certainly many different ratings of them intended for different applications.

One clue - given that 20W and 50W halogens cost the same, and you say your room is too dark, why would anyone have fitted the dimmer bulbs? I'm afraid the simplest answer would be that high power transformers do cost significantly more than low power ones (power is roughly proportional to cost), and the installer has saved money by installing a cheap, low power transformer.

A separate issue is that you'd need to check the rating of the light fittings themselves - quite often they are 35W max (might be a sticker left inside the shell somewhere?).

David

Reply to
Lobster

illogical sir.

No. The transformer will fry, the cable may melt and short, and the lamp fitting may overheat, melting cables and maybe causing a fire risk.

are they lighting ok? If so, 12v is coming thru.

I suggest this idea is not the best approach. Halogen downlighters are very inefficient and costly to run, and replacing 7x20w = 140 with

7x50w = 350w is frankly not the best move.

I'd add more lighting of a more efficient kind, such as uplighter, pendant light, wall mounted spot, anything but downlighting. Preferably using CFL. Now you still get the look of the halogens, but also decent light levels without paying through noth nostrils.

NT

Reply to
meow2222

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