Changing dimmer switch- was it wired wrong.

[EarSlaps]

I'm changing the dimmer for our down lighters so that I can use LED bulbs (current dimmer is a strange touch one and doesn't work with the two different dimmable LEDs I've tried, have now bought a varilight dimmer for LEDs). The lights are on two way switches so will have to change upstairs switches to on/off switches first.

I'm fairly comfortable with rewiring plugs etc and I took my dad's advice of photographing the wiring before I unscrewed anything!

I looked online and it said brown should be in C and black should be in live but mine looks the wrong way round? The house was completely rewired in 2004 so the wires should be the most up to date colours. The earth has been correctly wired into the bit on the front of the switch.

So should I wire it in the same way as it was, or correctly as per the Internet and my DIY book?

"The lights are on two way switches so will have to change upstairs switches to on/off switches first"

No, if your wiring is laid out for two-way switches (e.g. one upstairs and one down) then two-way switches are what you need. You can get two-way dimmers. Anyway, two-way switches can be used as one-ways when needed.

Two-way switches each have three terminals.

The cable you show is (presumably) three core and earth, which has brown, black and grey cores, plus a bare copper earth which should be sleeved in G&Y and go to the earth terminal on the switch and/or the metal backbox.

I can't find a wiring diagram for two-way switching plus dimmer in the new ("harmonised") colours.

Yes, sorry I meant I have 2 x 1 gang 2 way switches to replace the other dimmers upstairs (had trouble enough finding dimmers for LEDs without adding in master/slave). Then the dimmer is 2 gang 2 way.

Yes, it's 2 x 3 core cables in the downstairs 2 gang switch and 1 3 core cable for each switch upstairs, plus earth cables in green and yellow at each switch onto the earth terminal.

I'll have to take the other boxes off the wall to see how those ones are wired I think. It's complicated by the fact that the new switch has L1, L2 and C terminals, plus earth, and the other switch has the symbols shown on the picture.

as your old one appears to be a "slave" dimmer I can't guess how it is wired. This suggests that there is a "master" dimmer somewhere; or used to be.

If you can see a make and model on the old one, see if you can look up its wiring instructions, perhaps on the maker's website.

Yes, I think masters are the switches upstairs. I'll take them off to have a look.

Gosh there are a lot of wires in the switches upstairs!

One switch is a double but has wires to only one of the switches, and there are 3 cables in there, however one of those is taped up so not in use. The other is put like with like into the connector on the switch. Only one has the grey wire, which I assume is the cable that goes off to the slave.

The other one has two cables as above. On both the brown has been put in the 'live' section.

For our set up I was hoping to have on/off 1 gang two way switches upstairs (in the ones pictured here) and a dimmer downstairs on the slave.

Where did my pictures go?!

And the other

Pictures on installation instructions for both

Right, looks like none of my pictures loaded! I think there were a few issues with that.

I found this diagram online. That looks fairly similar to how ours is wired, except that in the master switch the black and blue (with brown sleeve on) are both wired together into 'Load' and the grey is loaded into 'Slave' on its own.

The old switch has 'Live', 'Load' and 'Slave' and the new switch has L1, L2 and Com so it's quite confusing! It is a Doyle & Tratt, which is now Varilight, with a minimum load of 40W, explaining why it won't take LEDs. I assume Live is L1, Slave is L2 and Load is Common? And can I use a regular 1 gang 2 way switch as the 'master' and the dimmer as the 'slave'?

I suppose I could continue using the switches and replace all but one of the halogen bulbs? But I really wanted LEDs for decreased energy consumption and so we can have decent insulation up in the loft! I know I could get an electrician in but surely replacing a light switch shouldn't be this hard?!

I am not familiar with the master and slave dimmer.

How would you feel about changing both the switches to ordinary two-way on-off switches (no dimmer) then when you are happy that is working correctly, take another look at the instrs for changing from switches to dimmer(s).

Having a single dimmer downstairs would be easier than the master-slave arrangement.

I haven't seen the wiring diagram for the dimmers you are using.

It is very bright with all the lights on full! The people who had this house rewired loved a downlighter! Yet, strangely, we don't have a single overhead light in the living room and it's all wall lights.

I'll see if I can get the photos loaded later, if MN will play ball...

I think until I can translate Live, Slave and Load to L1, L2 and Common I'm not going to attempt anything .