Dimmer confusion :s

[mlipscombe79]

Hey forum!

So I thought a nice simple double switch to double dimmer upgrade would take me 15 minutes. Wrong!
I'm confused between the old and new terminal labels and how my old switch was wired. Any guidance greatly appreciated!
Existing double switch = one switch controlled a light on its own, the other worked in conjunction with a single switch on the other side of the room. Unhelpfully most of the wiring colours are brown, so I have labelled them with a black marker with marks I, II, III, IIII etc.
All Blue neutrals are connected together.
Diagram of existing wiring and old and new switch pics are attached

Thx
Matt

 

[EFLImpudence]

What do the dimmer instructions say?

 

[mlipscombe79]

Hi. They are next to useless. Don't even have the connections labelled the same as the back of the dimmer!

 

[EFLImpudence]

I have this diagram from a Knightsbridge site but there is no model number.

It does though show the wavy line symbol as COM.

https://manuals.plus/knightsbridge/10-200w-5-150w-led-trailing-edge-led-dimmer-module-manual

Are you ok with that?

 

[EFLImpudence]

Don't mix up all the browns.

Brown IIII (with the link) must be Line(live) supply.

 

[mlipscombe79]

Many thanks, that looks like the same dimmer and I did think the new symbol would be common.
So I assume L1 is 1 way and L2 is 2 way?
What also got me a bit confused is that when testing with a meter only the brown wire with one mark (* on diagram) is live. Does that sound correct?

 

[mlipscombe79]

Correction.. you're right. Brown with 4 marks is live supply.

 

[EFLImpudence]

Ah Ok.

So I assume L1 is 1 way and L2 is 2 way?

Well, sort of but not really.
L1 is connected when switch is in one position and L2 when in the other position.

 

[mlipscombe79]

Any chance you could show me how to transpose existing wires into new dimmer via diagram? Sorry know that's a big ask, but going to loose daylight soon and being doing this with a torch..

 

[mlipscombe79]

Is this correct?

 

[EFLImpudence]

Sorry, I had to go out.

Yes, but i think the link wire to the left switch should be in L1 - but it might not matter.

 

[EFLImpudence]

It's just the line(live) supply wire to the left switch - nothing to do with the other switch as such.

 

[EFLImpudence]

They do it the other way round but that doesn't matter.

@mlipscombe79

 

[mlipscombe79]

Thanks for all your help.. the diagram I drew above worked!
Hope this helps anyone else. Instructions with the Knightsbridge dimmer were poor, but I guess they assume anything remotely complicated won't be done by anyone other than an electrician.

 

[EFLImpudence]