Light Switch (Dimming)

TheCore · Jun 19, 2013

Alright, well i signed up here because I have a question.

I'm new to the electrical systems etc, so here I go ;D

My light switch is a bulky switch, it sticks out of the wall (Has a white box then the cover, For EXAMPLE the plug sockets in the uk stick out of the wall, my light switch is similar to that)

I want to install a light dimmer, and the light dimmer is a small one that fits onto the wall, example
'http://www.diyfixit.co.uk/images/stories/how_to/electrics/light_switch_replacing/easing_the_light_switch_back_into_position_big.jpg'

Can I install this on the one that sticks out of the wall?

Richard Burns · Jun 19, 2013

If your light switch is on a 16mm back box then you will probably find that a dimmer will not fit.

[ElectriciansForums.net] Light Switch (Dimming)

If the light switch is on a 25mm back box then most dimmers will fit, though check when you buy the dimmer what the minimum back box depth is.

TheCore · Jun 19, 2013

Great thanks for the reply, I'll check tomorrow, does this needs to be measured from the inside of the light switch or from the outside and to the end of the box, before the cover plate?

telectrix · Jun 19, 2013

the 25mm is the outside depth of the back box alone.

Richard Burns · Jun 19, 2013

Quick estimate: from wall to top of the box, without the switch (cover plate) in place.

telectrix · Jun 19, 2013

25mm is 1" in english.

TheCore · Jun 19, 2013

Thanks, the one I was looking at doesn't give a minimum depth, I'll look else where, do you have any suggestions?

Richard Burns · Jun 19, 2013

There are too many variables to be able to give you a useful recommendation.
I do not know how many lights, the type of bulbs, the space you have available, whether the bulbs are dimmable, etc.
Most basic 400W dimmers will be fine for most basic non compact fluorescent lights up to four fittings.
Most dimmers will fit in a 25mm back box but some would get too hot when loaded.

TheCore · Jun 19, 2013

Alright, I'll probably go and check the space I have and check a few things out and then look into buying one, I'm guessing it'll be worth spending the extra few quid on a more expensive one?

ipf · Jun 19, 2013

Put a 47mm one on .............just to make sure. Stand out lovely.

telectrix · Jun 19, 2013

first, add up the wattage of the lights. if it's under 200watts, then a 250watt dimmer will do the job, unless it's halogen spots, then double the total.lamp wattage to select your dimmer size.