3 way non neutral help

Hi, I have a very old house… no neutral, wire with fabric on them instead of rubber… I have a 3 way fixture. One controler downstairs, fixture upstairs with another controller. All wired with 3 wires each, all look the same. So downstairs, i replace one controller with an inovelli black series dimmer. Configured it in smartthings to AC power type non neutral and smwitch type 3 way momentary. As long as the upstairs controller is on, the inovelli works. When i switch off the upstairs controller fixture goes off and inovelli does not work anymore. When i put the upstairs controller to on again, inovelli comes back to life and fixture to on. Tried to connect a GE add-on switch upstairs without any luck.

So right now i joined two wires in the upstairs box to simulate an always on fo the controller and taped the other wire. Any chance to make this work? either with the GE add-on or another Black Series (I have more in stock :wink: )

Thanks for your help

So in each switch box there are only three conductors coming into the box, in one sheath . i.e. a 3-wire? (We’re not counting the bare ground if you have one.)

Assuming that is the case, you have a power to the light non-neutral as you suspect. Two 3-wires then connect the light to each of the switch boxes. In this configuration, the Inovelli needs to go in a specific box. How did you determine where to put the Inovelli?

Also, in a non-neutral, you need to use an Aux switch. You can’t use a dumb switch. Your post says that you tried an Aux, which suggests that you were also trying it with a dumb switch.

If your configuration is what I think it is, you will have to do some rewiring at the light box.

This diagram provided by Bry is propably what you need to do for your wiring.

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Yep, that’s it!

Well considering the age of the wall and ceiling, re wiring is not really an option! in one of the box where i put the inovelli, the line (power) comes from the switch right next to it (in the same box) and the 2 other wires goes up the wall to upstairs. If I don’t connect anything in either upstairs or downstairs, the other one don’t do anything.

As for the add-on, this is what I bought (https://www.amazon.ca/gp/product/B00RKJS8MQ/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1)

If there is nothing to do i’ll just keep the cables twisted together upstairs, close with a plate and stick a smartthings button on the plate to control the on/off of the inovelli with smartthings (if this is possible)


By re-wiring, I mean making changing the connections in the light box, I don’t mean running new wires. Look at the diagram @djordan2112 referenced and you’ll see what I mean.

You have to be careful there. One of those to switches is receiving constant power from the light, and you’ve introduced another power source from another switch. Even if it’s the same the same branch circuit, that is a dangerous approach.

If you’re willing to use a button in place of one of the switches, then you should identify the switch box that is receiving the constant power from the light and put the Inovelli there. Then just wire the Inovelli as a 2-way non-neutral.

Is the line (power) coming from the fixture (light), or somewhere else in the switch box?

thanks Bry, the Line coming from the other switch was already like this with the old switches in place… that’s why i chose this one as this is the one we use most of the time. Also, i tried to see if they were independant but they don’t seem to be. If i connect nothing downstairs (leave all cable open) even an old dumb swith does not get power upstairs… and samething the other way around. If i connect nothing upstairs, all three wire connected to nothing, then i can not get any switch (old dumb or inovelli) working downstairs.

Ok, so that sounds different than what you first described. I understood that there was a ONLY a single 3-wire to each switch. But that’s not what you’re describing now, so what @djordan2112 and I posted may not be accurate for your situation.

(sorry, maybe my english is not that clear)… so downstairs, 1 wire coming from the next to it swich into the line, 2 wires leave in the wall… so 3 wire connected. Upstairs, there is 4 wire in the box, one cut very short in the back with nothing hooked on it, and three hooked to the switch.

If you’d like assistance, please post pictures . . . wiith the switches pulled out so that the connections AND INTO THE BOX can be seen. Give your boxes names so we can tell them apart.

thanks i’ll do taht after work