I am starting to convert my light switches to smart ones as I bought my Costco out when they had the 2 pack Feit dimmer switches for $7.
Flashed all 26 already with OpenBK, but I am having issues with my 3 way switches. They all are wired switch, light, switch with no neutral or power on the end.
Now the smart switch shows to wire it like the photo in the comment below.
The only way I can see how to do it is add either a neutral or live to the last switch. Like in the 2nd comment below.
Some of them would not be too bad as they have an outlet or another switch nearby on the same circuit, but others would be pretty hard. Are there any other switches that would work instead or am I missing something? Only other thing I can think of is if the travel wire is only measuring resistance vs voltage, I could connect the neutral to the last switch would also work then.
The short answer: physically wired it can’t be done without significant rewiring. The easy way to get it done anyway is one smart switch connected to the bulb the normal way, and one remote which controls the light through HA. There are battery powered switches that look like the hardwired ones. You could stick them to a wall anywhere or install them in the place of the original wall plate.
The only downside is when HA is down, only one switch works. But even that can be fixed, for instance by using z-wave and using associations to directly link the switch to the bulb. That is how I did it.
The way @Edwin_D is how every 3 way and 4 way I have setup is done.
GE/Jasco in fact sells their 2nd and 3rd switches as “secondary” to work just this way. Insteon switches are all the same model, but the instructions tell you to not wire the red wire and set them up through the hub as secondary switches.
I’ve never found a smart switch that isn’t made this way. In a 4 way that would be a special build the same way a non-smart switch is.
Unless there’s something special about these switches, you could install the smart switch where you have a neutral and leave the existing end switch in place. I’ve done this with several three way locations using TPLink smart switches.
During discovery, the Kasa app asked how many smart switches were installed. In my case the answer was one. That smart switch was then configured to work with the existing switch.
