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Joined: 22 Mar 2007
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 Posted: Thu Jun 28, 2007 6:48 am I am planning to change my lounge pendant light for 6 downlighters, the downlighters in question are 6 x 50w 12v each with it's own transformer all are prewired so i hope will make the changeover easier. The current lighting circuit is 1.0m t&e, would this wire be suitable for the 6 downlighters? Thanks

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 Posted: Thu Jun 28, 2007 7:41 am Loading will depend on what else is on the lighting circuit! In design a light fitting is calculated as 100W so you are adding another 200W to the max load. It should be OK assuming no larger than normal loads.

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 Posted: Thu Jun 28, 2007 2:41 pm http://wiki.diynot.com/electrics:lighting:lamps:gu10 Use 230 volt lamps and fittings. Then you can use CFL lamps if you so desire in future, when normal halogen bulbs are banned for their inefficiency and bad lighting. Also bear in mind 12 volt lamps use NO LESS electricity than 230 volt lamps. A watt is a watt, wattever the voltage.

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Posted: Thu Jun 28, 2007 3:58 pm

 Quote: Also bear in mind 12 volt lamps use NO LESS electricity than 230 volt lamps. A watt is a watt, wattever the voltage.

P=IxV

I=V/P

so wouldnt it use less current? I've never bothered thinking about it.

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 Posted: Thu Jun 28, 2007 4:00 pm they are the same.. "The fact is that the voltage does not matter, just because a lamp runs on 12 volts does not mean it uses less energy than a normal filament bulb. It is the Wattage that counts and only the wattage." source - ah lost the page lol.

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 Posted: Thu Jun 28, 2007 4:01 pm If you have a 50w lamp at 12V it will draw more current than a 50w lamp at 230V. But since power is a combination of voltage and current they still use the same amount of electricity.

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Posted: Thu Jun 28, 2007 4:32 pm

 Crafty wrote: http://wiki.diynot.com/electrics:lighting:lamps:gu10 Also bear in mind 12 volt lamps use NO LESS electricity than 230 volt lamps. A watt is a watt, wattever the voltage.

This isn't quite true because the transformer also consumes power - i.e. wattage out doesn't quite equal wattage in. So actually they use slightly more.

If you feel the transformer body when the lamps are in use, it will be warm because the lost power is converted into heat.

A further complication is that not all lamps emit the same amount of light for a given wattage - e.g. more light per watt for a fluorescent source which is why they are considered to be greener.

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 Posted: Thu Jun 28, 2007 6:46 pm That's true for traditional wire-wound transformers. there's iron losses and copper losses. Most transformers used in 12v lighting use mostly electronics to transform from 230 to 12v and there is very little loss so, for the purposes of this (DIY) thread, they can be ignored.

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 Posted: Thu Jun 28, 2007 7:24 pm so which is better out of mains voltage DL's or LV DL's?

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 Posted: Thu Jun 28, 2007 7:35 pm low voltage apparently give a nicer light to the trained eye but CFL energy savers are not available in 12 volt. mains voltage are easier to install and energy saving lamps are becoming more widely available. Therefore mains voltage is likely to be specified more in future as filament lamps are outlawed in the next few years.

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 Posted: Thu Jun 28, 2007 8:46 pm Plus, there's less maintenance with LV downlighters because there's no tranny.
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