Sizes of In-wall Relays (FYI)

I was recently contracted by a client who wanted smart control of his switches, but wanted his existing switches to remain. The solution, is to use "in wall relays".
However, given, that the house is relatively older, the internal junction boxes ("gangs"), are relatively small. Here I present the actual sizes of the three smallest dual channel devices that I could find.
(Note: There are significant differences between these, but if size is your key parameter, this should help you decide.)

Type Protocol Size
Aeotec Dual Nano Switch Zwave + 4.318 x 4.064 x 2.032
Shelly 2.5 UL WiFi 4.2 x 3.6 x 1.4
EnerWave Zwave + 5.156 x 4.369 x 1.575
Quibino Flush 2 Zwave + 4.06 x 3.56 x 1.52
Fibaro FGS 223 Zwave + 4.24 x 3.81 x 2.032
RGB Genie ZW-4001 Zwave + 4.55 x 5.50 x 2.03
Sonoff ZBMini Zigbee 4.26 x 4.26 x 2.0
RGB Genie ZB-4002 Zigbee 4.55 x 4.50 x 2.03
Zooz Zen52 Zwave + 3.81 x 3.6 x 1.8
Sonoff Mini R4 (Extreme) WiFi 4.00 x 3.3 x1.7

(updated on 2022-12-14)

If anyone is aware of another dual channel device that is comparable, please let me know, and I amend this chart.

Please note: For our European friends, (from what I understand), size is not an issue, as there is plenty of room inside the junction box. Also, the newer, North American plastic boxes are also much larger.


FWIW, Qubino Flush 1 and 2 ZWave+ in-wall relays are also very small:

1.65" x 1.45" x 0.66" (or in cm: 3.65 x 3.21 x 1.46)

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Thanks. Modified my chart.

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Thanks - that size is for both the Flush 1 and the Flush 2. The Flush 1 has a single 10A relay, and the Flush 2 has dual 4A relays.

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I used the numbers found on (since I could get all the products there.)
Are my numbers incorrect for the Flush 2?

They are the same size though height may vary slightly. Even the Flush 1D dry contact relay is the same size.

IMO the Qubinos are not my favorite devices. They are pain in rear to exclude if you ever have to reset them and the dual relay was spamming my zwave network causing problems. But they are very small.

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I went by the numbers on Qubinos website. I have a couple Flush 1, with no real issue to speak off. But I haven’t had to exclude them.

I just measured my Flush 2 and @aaiyar measurements are correct.

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Fibaro fgs-222, fgs-223 and fgs-224 are another option

1.79 x 1.77 x 0.8

Nevermind .. Scratch that .. just noticed you mentioned dual relays..

The reason that I used dual instead of single relays is because with old metal boxes, I just couldn't fit a relay controller in!
Maybe a professional electrician could do it, but I certainly can't.

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Anyone know the benefit of using a ZBMINI instead of the ZBMINI-L if you do happen to have a neutral wire?

The new ZBMINI-L2 (currently OOS) is no neutral as well, but smaller footprint than both.

If you happen to have a neutral wire, then you should install the version that requires neutral. This means that it could be used as a switch not only as a dimmer.

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