How to rate dimmers

[andemz]

Hi all. Just needing to know how to rate dimmers. Say you have 300W of GU10's and you want to be able to dim them using a dimmer, i know that you have to have specific rated dimmers and i've read somewhere that there is a calculation for working it out.

I also have 500W of GU10's that i need to dim how do i work out that one and are there any considerations into the calcultaion for 2 way dimmers when using 2way...

Thanks in advance

 

[breezer]

reduce the dimmers rating by 50 %

 

[andemz]

ok so if i had 300w of GU10's then i need a dimmer rating of 600W.

If that is correct you know my next question. Do they do dimmers that are rated over 1000W i.e. dimmers 1500W.

Please point me in that direction

 

[breezer]

what's wrong with a 1000w dimmer for your 500w of gu10s? tlc supply them

 

[andemz]

this is what's wrong. http://www.tlc-direct.co.uk/Products/VL1000.html that is the only 1000w dimmer they have.

Take for example my kitchen, quite a big kitchen. I have a 4 gang light switch. now i cannot find anywhere where by the dimmers are rated high enough for my needs.

Even getting a quality 2 gang 2 way dimmer 1000W is becoming difficult. Price is not an issue, it needs to look good.

 

[breezer]

can you not split the ccts.

and besides you dont want 2 way dimmers, they are a pain in the (insert word of your choice)

ok if money is no object send me £4, 500 and i will come around and do it for you. (and for that money, yes they will flash in patterns too )

 

[andemz]

why not make it £5,000 that should sort it, you can put me a nice watergarden feature in whilst you're at it.

In answer, yes i could split the circuits but i hate seeing 2 2gang switches next to each other, looks naff.

Having said that i will split the living room switches. I have just had another look at tlc and they have a IQ range, i read that these dimmers have been re-rated so that when it says 600w then that's what it will take

Mains Halogen Lamps



400w Infra-red/Touch dimmers only


600w Infra-red/Touch dimmers only

400w Single IQ Range
500w Single IQ Range
300w Double IQ Range


Our dimmers have been re-rated for GU10 Lamps
and are able to dim GU10 lamps to the wattage stated on the dimmer

4 Gang 2 Way 4 x 250w Dimmer Chrome

I don't like the touch dimmers.

I also take your point about 2 way dimmers, i guess they could be a bit of a pain.

 

[breezer]

2 way dimmers are a pain, but seriously i can install a lighting system for £4,500 you did say money was no object, so where shall i send the invoice to?

 

[ban-all-sheds]

I'll do it for £4,250.

 

[andemz]

Electricians for you you really would take the money from a young man trying to make his way through life whilst at the same time being taxed heavily by Tony and his cronies (yes that includes you GORDON).

 

[delmel]

Hi all. Just needing to know how to rate dimmers. Say you have 300W of GU10's and you want to be able to dim them using a dimmer, i know that you have to have specific rated dimmers and i've read somewhere that there is a calculation for working it out.

I also have 500W of GU10's that i need to dim how do i work out that one and are there any considerations into the calcultaion for 2 way dimmers when using 2way...

Thanks in advance

Why the hell did you use GU10 they are crap, low voltage 3 times more efficent, lamps last longer (if branded) and easier to dim. Most manufacturers say to downrate dimmers to at least 30% when using GU10. MK say dont use. Install some transformers decent ones (only IBL) and change the lamp & holder. You will find much better & nicer light. You could then reduce the lamp if required to 20w each.

 

[andemz]

That opens another debate on whether GU10's are rubbish compared with LV. From a practical perspective. The LV downlights couldn't be put where i wanted to as i was governed by distance, the LV's don't give much distance to work with.

For example my living room is around 30ft long and 15 wide. If i wanted the LV's in thier, i would need a few tansforers, even if it was just one transformer i would need to find an accessible space for it. Which i haven't got.

Instead my joists in my living room are 9 inch deep, which gives plenty of clearerence for my GU10's. Put a dimmer on on split switches and they do a real good job. Ebay do a very good range of GU10 buklbs for next to nothing i could replace them as i want because i came across 50 30W and 50 50 W also at a local auction for £50. Now that's as cheap as chips.

 

[Mug-o-Latte]

When you say a 2 gang dimmer is rated 300w, is this 300w per dimmer switch i.e. the switch could support 2x300w circuits, or does this mean 2x150w circuits (or some combination that doesn't exceed 300w in total)?

 

[ban-all-sheds]

Why the hell did you use GU10 they are rubbish, low voltage 3 times more efficent,

Really? Can you back that up by posting links to lamp manufacturers websites where they quote lumens/watt for ELV and LV halogen lamps, the latter being one third of the former?

lamps last longer (if branded)

Not always true. Different manufacturers at different price points quote different lives. In both cases it's a spread of lengths with a lot of overlap. Some mains halogens are longer lived than some 12V ones, and in a lot of cases the differences are so small that if you were concerned about them you'd not be using halogen lighting in the first place.

and easier to dim.

I disagree - you still have to select an appropriate dimmer and you also have to ensure that the transformer is suitable for dimming - more complication, not less. And even then, there's a reasonable chance that the transformer will generate an annoying buzz when dimmed.

Most manufacturers say to downrate dimmers to at least 30% when using GU10. MK say dont use.

From http://www.mkelectric.co.uk/PDF/technical/Logic_Plus_Dimmer.pdf:

Features

Intelligent Dimmer Switches
incorporate the following advanced
features
.
.
.

Soft Start, which gradually increases
the light output from the load over 1
to 3 seconds after switch on. The Soft
Start feature is also particularly
beneficial when used to dim Mains
Voltage Tungsten Halogen lamps which
have inherent very high inrush current
at switch on.
Features

 

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