Dimmer Switches

[Jones77]

Please can someone tell me what wattage dimmer switch i can use for a 4 x50w halogen strip spotlight? and what is required for general ceiling lights? also can they be used with recessed halogen spots?

Thanks

 

[Steve]

use a 400w dimmer. And yes, they can be used with recessed lights.

 

[gregbbb]

crafty

Why would you use a dimmer twice the rating of the spotlight? I have seen this mentioned before but no explanation given.

If I am using a spotlight with 4 X 50W bulbs would I be in trouble in using a 200W rated dimmer?

Cheers

 

[Steve]

The key here is halogen.

Halogen and low voltage loads tend to have higher startup currents, since the resistance of the halogen's filament is lower when cold and the transformer needs to establish a magnetic field.

So the dimmer must be rated to switch twice the given load, unless it is specifically rated to take into account these startup surges, or buy an "intelligent" dimmer which are practically indestructable.

 

[securespark]

or buy an "intelligent" dimmer which are practically indestructable.

Not when I'm wielding a hammer they're not!!

 

[gregbbb]

If the dimmer said it was compatable with halgoen lights would this indicate it is "specifically rated to take into account these startup surges"? Or does it need to be more specific?

I'll check the instructions anyhow.

FYI it's the following dimmer....

//www.diynot.com/shop/GET_Ultimate_Flatplate_250w_2_gang_Dimmer_Switch_WSS/21815

 

[Steve]

secure you know what i meant. those intelligent dimmers by the likes of varilight can be wired up to practically anything and still work!

and bashdem, that dimmer looks like a good quality one. Not sure about the GET brand, but I would expect "suitable for halogen", or usually any mention of "halogen" meant they dont need de-rating.

 

[gregbbb]

bashdem, that dimmer looks like a good quality one. Not sure about the GET brand, but I would expect "suitable for halogen", or usually any mention of "halogen" meant they dont need de-rating.

Good to hear, I'm planning on using 4 x 50W bulbs (= <250W) so I'm now off home to trawl through the instructions/small print looking for the word "halogen"

Cheers, will keep you updated.

 

[gregbbb]

OK, I checked the instructions and it states, under Tungsten Lighting,....

"In using 230V Tungsten Halogen bulbs the maximum loading of the dimmer must be halved"

So my 250W dimmer becomes 125W - is there such a thing as 30W spotlight bulbs??? If so, what kind of light would you get off of these? There'd be 4 of them in the following unit....

http://www.nextdaylighting.com/ItmImg.asp?ItmCd=125924

..and 2 of these units in 1 room (15' x 10')

 

[Jones77]

Thank you for your answers - very interesting

 

[Steve]

bashdem, there isn't such a thing as a 30w halogen lamp, but i recommend the following dimmers, as you need a replacement by the sounds of it!:

http://www.tlc-direct.co.uk/Main_In...s_All/Wiring_Accessories~Dimmers_5/index.html

touch control and you can programme a button on your TV remotes to control them. And I was saying above, these varilight dimmers are practically indestructable.

Maximum load must be reduced by 25% for mains voltage halogen & candle bulbs

only 25% and they make them up to 600w