Zigbee dimmer / switch module inside metal back box


I am a new user, looking for some help from more experienced Hubitat users. I do not have the Hubitat yet, however I hope to start my home automation adventure in near future, starting with making home lighting "smarter".
Light switches have been upgraded over last 2-3 years to screw-less, brushed steel ones - wife is not too happy to change them again. So I'm planning to install Zigbee switch modules and dimmer modules inside the existing back boxes. Examples would be Samotech SM323 for dimming and SM308 for switching.
My concern is if they will communicate with the hub & other devices if installed inside metal back box and with metal face plate (switch)?
I hope someone have done similar installation and can advise if this will or will not work.

Thank you for reading and apologies if this has already been answered elsewhere.

Kind regards,

I have similar to the 323 in the form of a Candeo dimmer module in a metal back box with a metal face plate, its in the summer house around 8m away from the house and has been working fine. I don't think you will have any issues. Your biggest concern would be cramming it in the back box with the original switch, looking back I wish I had done this to make it look more hidden.


Welcome to Hubitat.

I have two SM323s working in my kitchen with a metal faceplate, I just removed the original dimmer units and replaced with the SM323 units which has achieved wife approval.

I also would recommend that you look at the Hubitat Motion and Mode lighting Apps if you intend to use motion detection to trigger them.

Good luck with your home automation project.

@AverageJoe90 @chrisg
Thanks for your advice. Looks like it should work fine. Time to start putting my shopping list together.

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Hope you have saved your pennies!

As for metal back-box - I have several Samotech (Zigbee) and Shelly (WiFi) switch/dimmer modules installed in them, along with metal facia plates. They all communicate just fine.

If depth is an issue & you don't fancy the idea of chiselling out for a deeper back-box you can get a Pattress Spacer to create more depth but that's likely to score low on WAF.

Before you crack open the wallet, check whether your wall switches have a Neutral feed in addition to the UK norm of just Live & Switched.

In the UK Samotech would be my recommendation for "no-neutral" Zigbee switch/dimmer modules but I've literally JUST noticed they've changed their product range so you'll need to double check.

The Shelly (WiFi) "no neutral" modules need a bypass with very low wattage bulbs. The "bypass" is essentially a small capacitor unit that you fit in the ceiling rose, bridging the switched live & neutral connections to the bulb.
Personally I wasn't comfortable with the amount of heat generated by the bypass units & won't use them. I only use the Shelly's (that I'd already bought) for higher load circuits & use Samotech for the rest.

The responses you've gotten here are somewhat surprising to me. Maybe it has something to do with the density of the metal cover plate. But then I'm thinking - "those boxes might not even be fractionally consistent with the wavelength involved". Are these boxes fully enclosed metal boxes except for the cover plate ?

Many folk have done all they can to get these radios OUT of metal boxes :crazy_face: (like metal outbuildings etc.).

But field truth is field truth ...and if these guys have success I'd relish that news BUT not so much that you aren't planning where you'd place repeaters in those rooms to improve the odds in a "line-of-sight" fashion (if things didn't work out as well for you).

Do a TRIAL RUN before buying the whole lot :flushed:

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