Identifying wiring when you can't trust the colours..

[gsetdi]

I'm trying to work out the current wiring on a 2-gang switch. The switch is 2-gang and 2-way but is wired as 1-way on both switches.
The are 3 x 2 core and earth cables connected to the switch. The black wires of all three are connected to each other but nothing else, the same with the earth.
The red cables go one to each of the L1 terminals on the switches, and one connected accross the COM of both switches.

How can I identify which of these does what so that I can add a second (2-way timer) switch to on of the lights?

I'm epuipped with a multi meter if that helps...

 

[breezer]

easy, mark each wire, and make a drawing of which wire goes where, since you will be changing just one switch it must be wired the same way as the one it replaces.

The blacks sound like they are neutrals (shouldn't ideally be there)

the red that links from one switch to the other is the live, the other two reds are switch wires to the lights

 

[gsetdi]

Thanks for the reply, you've cleared up some of my confusion....

I'm not actually replacing a switch I'm looking to add a second one onto one of the lights of the current 2-gang. The new switch is a Security Timer (SuperSwitch) which seems to be wired slightly differently, in that it requires costant live. The docs with the switch also suggest that live should not go to the other ordinary switch and show L1 as not connected. I am guessing this is to keep a constant supply of power to the timer switch, although it doesn't mention this explicitly anywhere... Any ideas why?

So my plan would be to take the live out of the "COM" on the switch in question and connect it via the red of a new 3 core and earth to the "live" input on the timer. The lamp wire (currently L1) would then be moved to L2 where it would join the blue of the 3 core whic is connected to the "Load" connector on the timer. Lastly the "COM" would connect up via the yellow wire to the "2-way" connector on the timer.
Does this sound right? (it's based on the diagrams supplied with the timer)

The live would still be connected to the "COM" on the other gang switch, will this affect the constant power required by the timer?

 

[breezer]

in theory it wont work at all because ther is no Neutral to run your timer, but that said i have seen "automatic switches" that should'nt work but do, because they rely on a back feed through the lamp they are controling.

Can you post / draw a picture of the diagram you have?

 

[gsetdi]

Here's a link to some diagrams I've knocked up...

Fig. A shows the diagram printed on the back of the timer around the 3 terminals, I think it is suggesting that the Neutral is "back fed" from the lamp (??).

Figs B, C & D are the ones supplied with the switch showing possible connections for 2 way.

Fig E is my current wiring.

Fig F shows how I guess/interpret the switch should be wired to my current setup.

I have intentionally left out earth so as not to clutter the diagrams, as it is only ever connected down to earth...

What do you think? Would/Should "Fig F" work??

Thanks

 

[breezer]

if in your figure F the red wire where it says live, if that terminal is on your new switch then yes it should work.

 

[gsetdi]

Well I wired it up (as fig F above) but it didn't behave the way I'd have hoped....
The light switches on with either the timer or the original switch but then can only be turned off by the same switch. The original switch (a dimmer) doesn't dim, it just turns the light into an disco light, it blinks on and off a couple of times a second.

I forgot to mention that the original switch was a dimmer, does this need to be wired differently? Could this just be a fault with the timer switch?

Any Ideas??

 

[breezer]

anything else you forgot to mention?

It sounds like it is back feeding through the dimmer, it may be just the brand of dimmer you have, do the "time switch" instructions say any thing about not being suitable to be used in conjunction with a dimmer

 

[gsetdi]

Erm, sorry about that...the house has dimmers on just about every light, the previous owners went a bit mad with them...So I didn't really think about it being a special case, until the lights started blinking that is...

Anyway, the only other thing I haven't mentioned is that the light itself is mains voltage Halogen (2 x 50w/240v), I don't know if that has any bearing on things.

The instructions for the timer switch mention nothing about dimmers. There's just something about not working with flourescent or other discharge lamps unless they contain a Factor Correction capacitor, but I don't think this applies...(does it?)

Do you think it would be worthwile trying the approach in Fig B above?

 

[breezer]

I just noticed that the drawings are what you did, they are not from the instuctions

am i correct in assuming that you want to be able to turn the light on / off from either switch and when you want it to the "time switch" to work as it "does" ?

If this is the case the answer is no it will never work because your new switch must be a 2 way switch as must your switch you are replacing

 

[gsetdi]

drawings B, C and D were as supplied with the timer, my scanner is knackered so I drew them instead, I also included my current wiring (Fig.E) and my best guess at how it should all be wired together (Fig F) for clarity.

The timer is designed to replace a 1-way or a 2-way switch.

The existing switch is a 2-way/2-gang dimmer that is currently wired 1-way. I want to re-wire this existing dimmer as 2 way connected to the New timer switch which is also 2-way compatible. I'm not actually replacing any switches, just adding the new "timer switch".

Fig A, is a drawing of the 3 terminals on the back of the new switch, which are marked "2-way", "Load" and "Live", they are incorporated into the diagram, which is actually printed, as shown, on the the back of the switch.

 

[breezer]

sorry, i must have been asleep, you did mention that in the first place as does your drawing show a 2 way switch, i will see what i can draw for you much later today

 

[gsetdi]

Hi Breezer,

Did you manage to come up with anything?

I tried various combinations of the diagrams b,c and d but all with the same results...

 

[breezer]

It should work, perhaps your switch is faulty?

You could always send it to me and i can test it, if you really want to.