Feed sx output from 1 fibaro dimmer to the L input on another

Can anyone tell me if the following will work and is ok to do.

Can you connect the Sx output from one fibaro dimmer into the L of another?

The reason I want to do this is so that I can add control of a lighting circuit that is not currently wired to the switch in question. The switch in question is currently the end of the line on a 3 way circuit which had a dimmer at the other end. Basically this means I will have the Sx output from another switch at the common.

Hope this makes sense.


From a quick google, no it’s not ok to do it that way.

As long as you can power both dimmers in the locations you need, you shouldn’t need to run any extra cabling, you could do it all via smartthings or z-wave.

Do you want to be able to control the lights separately from a wall switch or just have them all do the same from the wall switch?

If you just want them all on / off / dim at the same level from the wall switch, you can use smart lighting to “mirror” the dimmer at the wall switch or set a z-wave association from one dimmer to another.

I could be wrong on this second bit, as i’ve never tried it myself… but if i am, i’m sure someone more knowledgeable will pop along and correct me.

If you want to control them separately from the wall switch, you could even go as far as replacing the front plate of the 1st switch with a double switch plate and use s2 on the 1st dimmer to send commands to the second dimmer via z-wave association.

Think I will need to draw a pic as not explained it very well. What did you search on to find the no answer?

I simply searched fibaro sx, and got taken to the fibaro forum where someone was asking the same question and was told not to by a couple of members, one of which was an admin for the forum.

Thing my searches had been too specific!!

Having a read I think the scenarios are a bit different.

Attached a sketch of what I have so far and what I am proposing (simplified).
All this is in one room so all feeding off the same circuit from the Main distribution board.
I basically want both lights to be 3 way but currently only have the wiring for one to be 3 way I.e. switch position 3 has o lay one 3 core + earth to switch position 2.
The 3 core from switch position 2 will have the Sx output on the COMM line to the 3 position retractive switch.

As I am missing a physical cable to be able to control the current 2 way circuit I was hoping to use a dimmer at position 3 to group with the dimmer at position 1. To do this I need a live and was hoping I could use the Sx output from position 2. Then the rest of the dimmer would be connected as standard to the toggle switch.

Is this a no no? I think it would work but may be electrical bad practice?

Cheers in advance.


Just to clarify… I take it you are wanting to control the lights independently of each other from each of the 3 switch locations. Hence the use of 3 position switches?

Based on the above drawing i’m thinking you are wanting something like this…

D2a S1 input to control the 1st light & D2a S2 input to control the second light.
D2b S1 input to control the 2nd light & D2b S2 input to control the 1st light.
D2c S1 input to control the 1st light & D2c S2 input to control the second light.

If that’s the case, all you need to do is replace the switch at location 3 with a 3 way switch and associate the 3rd dimmer (D2c) S1 to send commands to D2a S1 and then D2c S2 to send commands to D2b s1.

The 3 core into position 3 is connected to position 2 it is setup as per the attached

So therefore no neutral at position 3 and only a Sx output from position 2 on the COM line.

So I think the question still is how can I power a dimmer a position 3?

Is this to control both lights separately from any of the 3 switches? if so…

For d2c wire the com from location 2 into L on d2c (this is the permanent live that’ll supply voltage to the dimmer).

Then wire the 2 outputs from the 3 position switch in location 3 in to d2c s1 and s2 respectively.

use a 3 way connector block and wire SX, N & the com on the wall switch together.

Don’t bother connecting anything to the output on d2c.

Essentially you are using it as a wireless switch to tell the other two dimmers what to do.

You will need to initially wire it into one of the other locations to allow it to to do the auto calibration and make sure you disable auto calibration in the DTH for this dimmer after you’ve run the 1st auto calibration.

Then use z wave tweaker to set associations to the other two dimmers.

I.e S1 from d2c sends commands to d2a output
& S2 from d2c sends commands to d2b output

Hope that helps.