I want to install a double dimmer but once i have taken the old switch off all the wires are brown apart from the earth wires. i need to know if the L1 is live or the common is live, can any body help?

lee, May 2009

Hi,

I'm changing a standard double light switch to a double dimmer. In the switch box I have a red, a blue and a yellow wire (and an earth into the back of the box). The existing double has an upper and a lower set of connectors with red into comms at the top and that is linked to the comms at the bottom. Blue and yellow go from L1 top and L1 bottom.

When I replicate this set up on the new dimmer switch only one of the two lights will work. I can change blue/yellow to choose which one works but cannot get both to work. I've tried various combinations but simply cannot resolve this. Can you assist?

With thanks

foakesy, October 2009

On your old switch Com is always Live (should always be Live by convention) and L1 is Live too but only when the switch is in the on position.

Com is the power coming into the switch and L1 is the power running off to the lamp.

Peccavi, May 2009