dimmer switch identification

[southwesterly]

I have got a 2 gang dimmer switch for 1 way switching but I don't know if it is for 240V or 12V operation. Is there a way to tell from looking at the back of the switch. Also there is no indication on the rear to show where the feed should be connected. There is no earth connection point presumably because it is all plastic.

Can anyone help?

 

[breezer]

all dimmer switches (unless specified) are for 230v ac operation. if you have selv (12 volt) lights you dim the primary (mains) side of the transformer.

If you do this you should also downrate the dimmer by 50% and the lights transformer must be suitable for dimming.

You should also only have 2 wires (live and switched live) it does not matter which way round they go.

There is no earth terminal on a plastic switch.
the earth wire should be connected to the earth terminal in the back box (and sleaved with green/yellow sleaving)

 

[southwesterly]

Many thanks for the superfast response!

I have hooked up five 240V 50W downlights to the dimmer and they all work ok but they are not quite as bright as normal on the max setting. I guess that the dimmer switch may only be rated at 250 watts maybe??

 

[breezer]

you should be using a 500w dimmer, your current one will probably give up soon

 

[southwesterly]

I have taken the dimmer off now and put a normal switch on but the ligfhts still don't seem as bright as a 12v 50w lamp- they seem to burn with a slightly yellow light. I have never used 240v dichriocs before. Do you know if they generally look yellow rather than bright white?

 

[ban-all-sheds]

Yes - they are not quite as white, but unless you've got both in the same room, or you spend a lot of time looking and thinking about it, you soon won't notice the difference.