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srt0122 · Joined: 08 Oct 2004 Posts: 1 Location: Hitchin HERTS

I am decorating my kitchen and want to replace the current lighting with low voltage spot lights
What I don't know how to work out is how many spot lights I can have to one switch.
The design I want to use consists of 14 50w lights / which I may reduce to 30w if too bright.

b · Posted: Sat Oct 09, 2004 1:07 am Post subject:

The number of lights you can have on the circuit is dependent on the amperage rating of the wire and breaker in your circuit. Is there any other load on that circuit? It also depends on where you are in the world as to the voltage used in your area to do the calculation ie... in the states we are on 110V for lighting. Power (total wattage) = Voltage x Amperage
Therefore, 110V x 15A = 1650 Watts So you should be able to have the 700W of lights you mentioned on one circuit. You also mentioned using 30 watt lights if too bright... maybe a dimmer is a better alternative there. That way you can turn the lights to the brightness level you desire for whatever you are doing in the room.
b

vince knight · Posted: Sat Oct 09, 2004 5:05 pm Post subject:

count up all of the wattages of the bulbs that u have on the downstairs lighting circuit.
presuming the fuse/breaker in the fuse board is a 6amp.

14 x 50w = 700w
700 divided by 230v = approx 3amp

if you do the same calculation for your remaining bulbs on that circuit and the total amp loading is not above the rated current for the fuse/breaker(6amp) then you will be ok.

All light switches in this country are rated at 10amp min so 14 on switch is ok.
If you are going to dim them, make sure the dimmer can handle transformers and its load rating is equal to or greater than the lighting load.
PS
Nobody makes a 700w dimmer so they will have to be split across two 400w dimmers.

Hope this helps

Vince Smile

securespark · Posted: Wed Oct 20, 2004 10:56 pm Post subject:

No, but 1000W single gang dimmers exist.

And MK make a two gang 650W dimmer.

vince knight · Posted: Thu Oct 21, 2004 4:28 pm Post subject:

The 1kw dimmer you mention has a very small coil and is very unreliable and I wouldn't use it for more than 400w inductive. I can't find a current 630w dimmer by MK but they do make the K1710WHI which is rated at 500w for low voltage lighting. Home automation make a 630w but it gets very hot, is noisey and you will replace it within a year.

Vince

securespark · Posted: Thu Oct 21, 2004 9:59 pm Post subject:

Yeah, I matched the wrong data with the product.... Embarassed

vince knight · Posted: Fri Oct 22, 2004 4:29 pm Post subject:

No problem mate, we all make mistakes, just as long as they are little ones!!!

Very Happy

Vince