Confusing wiring on two-way switch?

[ban-all-sheds]

No I don't think you have the cable saving circuit,

Why not, given that there is only a 3C+E cable at each switch?

Can you see which, if any, of the wires are part of the same cable?

There is only one cable coming into each box, so all wires connected to the terminals come from the same cable.

Underneath the first diagram is another which is how a house gets wired with the two switches connected by 3 cores and the live coming in and out of one switch suing the L1 and L2 terminals. This 'in and out' can then be done with normal twin cable. Did you find this in one of the switches - not mentioned in your earlier posts but you need to make that one your 'master'.

The reason he didn't mention it in his earlier posts is that he hasn't got that system.

I think we have to take him at his word, i.e. that each switch only has one red, one yellow and one blue, and that he has not failed to spot a black and another red at one switch, or has spotted it but decided to lie to us.

(really pointless using little red sleeves to mark them)

Apart, of course, from the point of complying with the Wiring Regulations...

Now looking at the instruction sheet you linked to you see a circuit diagram that is just like the one on the wiki (but mirror image) showing ceiling rose, master and slaves.

Which is the master? The switch on the left, or the one on the right?

So if you have located the switch with the twin I mentioned above you should be home and dry.

But he hasn't got a switch which also has a T+E cable.

If either switch has a single, or a twin with only one wire connected ie being used as a single then STOP - it is not wired as per diagram.

What if it's wired with just a single 3C+E cable at each switch, neither also having a T+E drop cable?

 

[stavroshamster]

Thanks for all your help guys.

In light of 'ban-all-sheds' earlier post about me reading the information a bit more carefully I have to say you were spot on, and I hadn't read it all properly. Plus, I am a first-time houseowner and as such probably used the wrong terminology when talking about live and neutral - all my knowledge comes from GCSE physics which was a long time ago.

However, I wasn't planning on installing anything until I had a good idea about what was going on. I was just passing B&Q yesterday and decided to buy a slave and master touch dimmer to install once I knew what I was doing. Was in a bit of a rush to find out the answer - hence the quick-fire post which wasn't thought through properly.

Studying your comments and diagrams more thoroughly decided that a conventional dimmer switch would be easier to install. I have therefore taken the touch dimmer control back to B&Q and got myself a push on/off rotary dimmer switch which I have installed in the same way as the original switch. This works perfectly.

As 'ban-all-sheds' said, there is only one 3C+E cable going into each switch. There are no T+E cables to be seen. I have therefore made the assumption that the switches are connected to a junction box in some manner.

I would still be interested in determining what wiring set-up we have, even though the dimmer is now working. Is there a way of determining this with a multimeter?

As mentioned above, when the lights are off the COM and L2 terminals of switch 1 read ~240V, and the L2 terminal of switch 2 (dimmer) reads ~240V. All others are dead.

When the lights are switched ON from switch 1 there is 240V going to the COM and L1 terminals of switch 1 and the COM and L1 terminals of switch 2. All others are dead.

When the lights are switched ON from switch 2 there is 240V going to the COM and L2 terminals of both switches.

If you switch the lights back OFF in the other position that they can be off, there is 240V going to COM and L1 on switch 1, and to L1 on switch 2. All others are dead.

It is the voltage from the COM terminal which is adjusted in switch 2 if you move the dimmer knob.

Is this information helpful in determining what set-up there is? I don't know if I have studied the diagrams correctly, but am I right in thinking that it could be the Conduit method where there is a Live feed to the COM of switch one, and the load is connected to the COM of switch 2?