GU10s, dimmers, etc.

[phykell]

Hi,

I'm looking at doing the wiring for my kitchen. I intend to use at least 8 GU10 50W halogens and I want to know how to wire it so that I can use a dimmer. Obviously the total load is 400W so it's going to require a pretty hefty dimmer. If I've got it right, I'll need a 600W dimmer to control 400W of GU10s... So, looking at the type of switches I want, the flat black nickel ones, ideally I'd have a two gang unit, one for the lighting and one for the work surface illumination. Problem is, all the two gang units I've seen are 250W and in fact the largest single dimmer I've seen is 400W. Assuming I can get a 600W dimmer unit, I wonder if it's possible to replace one of the 250W ones in a two gang plate as a 600W unit may be prohibitively wide (fat). Can anyone suggest a solution or am I forced to either have two separate circuits for my lighting or downgrade the power of the bulbs amd increase the number to 10?

Thanks

 

[breezer]

have 4 dimmers (not joking) it will look nicer than 3 you should reduce dimmer rating by approx 50% so 400w of gu10 should have 800w dimmer not 600w

why not have 12v lamps and dimable transformers.

 

[Jasonb]

I have got round this problem by changing the workings out of a 1000w white plastic dimmer with a single 400Wmetal dimmer . If you need a double dimmer mount two singles side by side in a twin box (not double) as there is not usually enough room to fit two 400w ones in to a two gang switch.

Jason

 

[securespark]

You should be very wary of mounting dimmer modules > 250W in the same enclosure: heat build up......

Also, the deeper the box the better, for the same reason.

If in any doubt contact the manufacturer.

 

[dingbat]

The best advice I've come across is to use grid modules. Expensive, but very flexible and not totally unattractive.

 

[fluffys]

You can buy 1000w rate chrome dimmers here:

http://www.diysupply.co.uk/index.php?cPath=124_125_129&osCsid=182fe64af2eab554e23513e2be429b39

found after a long search! I got a couple and they are lovely. Excellent service from this company too.

 

[phykell]

1kW dimmers!

Regarding the flat black nickel fittings, I was looking in B&Q and the CCU is £40. At toolstation.com, the very same item is less than a tenner! Typical though, that they don't seem to list any dimmers at all! Thanks for the advice though, I'm now confident I can make something suitable if I use a double plate and a deep back-box. I certainly hadn't thought of using a deeper back-box...

 

[securespark]

You ask any manufacturer and they will state there are limits when mounting more than one dimmer module in an enclosure.

This from page 249 (dimmer grid section) of MK catalogue:

"Refer to MK technical services department for derating factors when more than one unit is used in any one box."

Just to check what you're thinking of doing is feasible, give MK tech. a ring 01268 563 000 and explain you want to put n dimmer modules of x value in the same box and see whether they laugh at you or not...

 

[ban-all-sheds]

You can buy 1000w rate chrome dimmers here:

http://www.diysupply.co.uk/index.php?cPath=124_125_129&osCsid=182fe64af2eab554e23513e2be429b39

found after a long search! I got a couple and they are lovely. Excellent service from this company too.

Hard for the service not to be excellent when they have virtually no products to sell....

 

[phykell]

why not have 12v lamps and dimable transformers.

Sorry, I missed this before. why would 12v lamps be any better? Surely if I had eight 50W 12v lamps, I'd be faced with the same problem? Or am I missing something really obvious (again)?

A friend of mine just commented that eight 50W GU10 lamps might be excessive in my kitchen as well. Is there some sort of calculator I can use to get an idea of how much light I need? I'm running six 20W 12v lamps in my bathroom, and it's tiny compared to my kitchen.