Which fibaro devices do I need?

Hi Guys

I’m looking to expand my ST setup. I currently have a couple of sonoff switches in my kitchen (with ewelink/IFTTT) but since I 1) have neutral at the switch and 2) have decent size back boxes I was thinking of using fibaro devices

But looking at Amazon, I’m confused by what I’d need for this setup :

Upstairs - 2 single switches that control the landing lights only (1 at either end of the landing)
Downstairs Hallway - A double switch which controls landing lights and front room lights
Downstairs front room - A single switch which controls the front room lights only

I’m guess I need a FGS-223 in the downstairs hallway, but what do I need at the other 3 switches ?

I don’t need anything to dim BTW just turn the lights on and off whilst preserving wall switch control


[Edit - My landing lights are LED spots and I have 2 ceiling roses in the front room, but there’s no individual bulb control]

You appear to have two light circuits, one for the landing and one for the front room. Each of these has multiple switches. Your statement that you have neutral at the switch - do you mean you have three wires plus earth?

If you only have two wires plus earth this means a single neutral wire. This in turn means you cannot use 3-wire only relays like the FGS-223 as this requires 3 wires i.e. two neutrals. Instead you would have to use a dimmer but could still have it act purely as an on/off switch, or take advantage of necessity and also have it act as a dimmer.

As both your lighting circuits have multiple switches you need to configure these in what is commonly referred to as a 2-way circuit i.e. like a staircase. Here is a link to a wiring diagram using a Fibaro Dimmer 2 module for this purpose. Not only does the Fibaro Dimmer support this 2-way design but it can also work with just a 2-wire (plus earth) cable.

As you can see you only need a single Fibaro Dimmer 2 for the entire circuit, with two circuits required you would therefore need two of these Dimmer modules.
Here is another wiring article giving an over view of alternative approaches, if you find the diagram that most closely resembles your current wiring (for each of your circuits) then you can click on the matching Fibaro Dimmer link to see the specific design for using a Fibaro Dimmer.

As an example the following shows a different approach using your existing ‘latching’ switches again with a Fibaro dimmer but this approach would not support dimming.

If you scroll down further in this article you will see both an example of using two switches and an example of using three switches. Your landing circuit has three switches and your front room two switches.

You will need momentary wall switches to control the modules and you will need to probably do some adjustment to your current wiring, it maybe that it will be easier to put the Dimmer module in the ceiling. Here is an article about momentary wall switches.

Note: There are other ways to implement 2-way i.e. ‘staircase’ type circuits. One is to have only one switch wired with a module (or in America a smart switch) and the other end with a wireless switch linked to the same module. The other is a very few smart switches can be configured so they are linked e.g. AOne Aurora Zigbee dimmers. However the article I linked to is the more common approach in the UK.

Many thanks for such a comprehensive reply. I had the 2 sonoff switches fitted by an electrician and I thought they had to have 3 wires plus earth ? Here’s a photo I took of the single switch before replacing with the sonoff (The neutrals were in the connector) :

and here’s a photo of a (different) double switch after replacing with sonoff :

So based on this, can I use FGS-223 ?


The nearest wiring diagram I could find to using the FGS-223 is the following

Based on this I would say yes you could use a relay for on/off control.

You can definitely use dimmers even configured for simple on/off. You would only want one relay per circuit and you have two circuits. If you use a location where both circuits are in the same wall box you might get away with a single double relay but you might find it easier to use two single relays.

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