Fibaro dimmer 2 in ceiling void

Hello all,

Can anyone tell me if it is safe to install a fibaro dimmer 2 (or other fibaro products) in the ceiling void?

Some of my back boxes are never going to be big enough so the next option is the rose which is also too small but can I go into the ceiling void above the rose?

This would leave the fibaro loose and in boxed.

Would an electrician sign this off?


No, it would be like having a connector block loose in the ceiling. I have had this issue and used all the following solutions depending on what was best at the location.

  1. Spacers at the switch plate. Schneider make some and you can get them Screwfix.
  2. Dig out the back box for a deeper one.
  3. Cut in a cavity box at the ceiling rose.


I’ve just fitted a fibaro dimmer at the ceiling rose and used this:

kwmobile Ceiling Pendant & Lamp Holder - Ceiling Rose & Light Pendant E27 Bulbs Fitting Set with 90cm Braided Fabric Cable - White Cable: Lighting


The metal bracket slotted behind the existing ceiling rose wiring plate and the new dome had lots of room to house the fibaro dimmer and a fibaro bypass

All the light wiring stayed in place on the existing ceiling rose wiring plate.

I replaced the E27 end with the old B22 end

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Nice one. I had been looking for oversized ceiling roses. Could be an option where I have pendants.

Might get the lec put junction boxes of some description for the downlights where there is no room behind the switch.

Cheers Simon,

Spacers are a no no for me for aesthetics.
Backboxes will be a deep as can be (47mm) but with grid switches and in some instances multiple dimmers needed at the same switch I am concerned space just wont permit.
Hadn’t realised these rose cavity boxes existed. Could be a great option in some places.

Trying to get it as right as possible whilst the building work is ongoing and befor plaster!


Agree on the spacers, but they do get you out of jail in some cases. If you’re not married to the idea of a dimmer the the double switch 2 is a good option. Must have a neutral though.

You could check with your electrician but I think you can put the fibaro behind one of the spotlights in the ceiling void if it is an accessible location, ie not plastered in, which a spotlight would not be (unless they are the plastered in type of spotlights of course LOL)

I installed it in the armature / lamp assy.

All of my Fibaro dimmers are in the ceiling void behind the first downlight fitting - very shallow backboxes and hard brick walls mean it’s just easier. Does need to be in some sort of enclosure though, not just loose in the ceiling void.

Chocboxes used to be perfect, but the Dimmer 2 now has a bulge where the terminals are and they don’t fit so well anymore :frowning:

I’ve used all kinds of tricks to make them fit.

In one room I’ve used a 2 gang back box to give more room and pushed it far back in the wall, and in the living room I’ve managed to get 2 dimmers in a 1 gang backbox by chiselling out the wall loads and fitting them behind the backbox :sunglasses:

Many thanks people. I am confident I can get it all in via some means. As I was renovating I wanted to make as many provisions as possible whilst the opportunity was there.
Also thanks for the clarity on not having them loose.