My experience getting a three way circuit to work with very small electrical boxes - Relay and Aeon Micro Switch to the rescue!

If you have a three way light you want to automate but it’s wired differently or the electrical boxes are very small or crowded, there is hope!

The stairs in my house have a three way light at the bottom with switches at the top and bottom. Standard three way type light, but there was some annoyance with adding a Z-Wave switch and coordinating remote. First, the wiring is not entirely standard. Next, the boxes are older metal boxes (1960s era house) and they are very small. After lots of frustration trying to fit Z-Wave switches in the boxes I took another approach.

I did it the way @Mike_Maxwell demonstrated here:

The idea here is that instead of controlling the load or the Aeon switch/dimmer directly from the switch, you’re controlling a solid state relay (SSR). The relay has a 110VAC input so it can be used directly in place of your load (light, whatever). The output of the relay is wired to the Aeon micro dimmer or micro switch as if it is a mechanical switch. To make this work, you’ll need the switched hot as well as an unswitched hot at the device you’re controlling.

I was lucky that, at the actual light fixture, I had the switched hot and also an unswitched hot. I used an Aeon micro switch, not a dimmer:

The SSR I used, and the one used in Mike’s demo video, is this one:

The wiring between the relay and the Aeon device is the same whether it’s a dimmer or a switch. Note that Mike used the 3V output from the Aeon into the SSR, which is necessary for a solid state device. If you were to use a mechanical relay this would not be needed, but those are typically bigger and make noise. If you have space, you could use this relay:

To put this all together, you’ll need to be handy with a soldering iron and electric tape or, better, heat shrink tubing. It’s not hard. Mostly you’ll want to solder 16GA stranded pigtails to the two input tabs of the relay and some light hookup wire to the output. Then put a bit of heat shrink tubing over each tab and you’re good. Watch all of Mike’s video to see which wire goes where. Yes, that demo demonstrates an Aeon dimmer application but the wiring is the same for an Aeon switch.

So there is one thing about those Aeon devices - they really are not all that small. I have been unable to fit them into some older boxes and all my luck with them this far has been in mounting them at the device I am controlling.

In the case of this light, it was still a tight fit. I had to get the wires, the SSR and the Aeon micro switch all into the very small overhead electrical box (remember - older metal one) and the light fixture. I ended up removing the yellow insulation and maneuvering the parts around just so to make it all go together:

There are a few advantages and disadvantages to doing your threeway circuits this way:


It’s actually cheaper. The Aeon device and the relay together cost less than a Z-Wave switch/dimmer and coordinating remote.

You can use any ordinary switches you like if it’s a simple on/off (not dimmed) application. If it’s a dimmed application you’ll need switches that act like pushbuttons.

I have found that in many cases it’s easier to fit the relay and Aeon device into the light fixture or fan canopy or whatever. For me, this has made it possible to automate a light I would not have been able to automate otherwise.


My Leviton Decora lighted switches still light, although dimly and they don;t keep proper synch with the load status.

You need an unswitched hot in addition to your switched hot at the load device location to make this work.

If it’s a three way dimmer application, you’ll need switches that act like pushbuttons. The Adorne paddle switches by Legrand can be modified (again, see posts by @Mike_Maxwell) to work as pushbuttons.