Dimmer on a two way circuit

Postby tedius » Sat Jul 21, 2007 2:28 pm

I've just installed some new halogen lights (on a track) in the living room. This all went find, and I have now replaced on of the switches with a dimmer switch.

This is a standard 2-way 400w push dimmer switch. The problem I have is that if I leave the standard switch in the on position then I can use the dimmer with no problems, but if I leave the standard switch in the off position then the dimmer switch has no effect. This also means that if I turn the lights off with one switch then I can only turn them back on by using the same switch. Is this normal when putting a dimmer switch in a circuit (before I put the dimmer switch in it all work as you would expect a two way circuit to work)

Another point I think I should mention. The house is about 18 years old and has a Loop-in lighting circuit, and in the switch I replace I had two wires coming in;

1. red, black and earth
2. red, and earth (This is the one that takes power to the light)

So I have 1.red and 1.black connected to the L1, and C respectively and 2.red is connected to L2, with both earths attached to the earth in the switch box.

Does all the sound right or am I doing something wrong?
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Simply Build It

Postby sparx » Sat Jul 21, 2007 9:02 pm

Hi, very unusual way of wiring a 2 way sw. would normally have 3 core/E
You say that one red 'is the one that takes power to the light' if u r sure about that then it is the one that should be in the com. term. not the black, which should have red sleeving/tape on it btw.
it seems the wiring was done with a tw/E looped between sw. as 2 way 'strappers' and a single core+E takes Live to one sw. and single+E takes sw.Live to light.
This is how it would be wired in conduit system using all single core wiring, never seen it done this way, but ......
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