3 Way Switch No Neutral - Very Confused Please Help

As I mentioned in a previous post, I did find two cables capped together in Switch A. I’ll attach that photo to the bottom of this post.

I hope all of this information helps make some sense of this and I’m sorry for not responding quickly to your posts. I had to wait for the wife and kids to be out of the house before I messed with this again. As my luck would have it, power for our internet is on the same circuit as the one I’m screwing around with and when I shut it off to work on this it makes me everyone’s worst enemy here.

I was happy to have found the constant 120v line in switch B. However, I was hoping that the other two wires in that box would alternate between 0v and 120v as you described in your first post. For a moment, I thought things were starting to make sense but… I’m still lost and completely clueless on where either of the Inovelli or the GE aux should go. Thanks again for your help!

Here is a photo of the inside of the box for switch A:

It looks good. I’m going out tonight but will try to get a sketch going tomorrow. You will have to change the wiring at the light, is this possible?

BTW you should document the current wiring and any changes in case you want to revert to what you have now in the future.

John

In each case I’ve included a bypass which may or may not be required.

There is the wiring for your LZW31 and a dumb 3-Way.

Image removed as it was pointed out a non-neutral installation with a dumb 3-way is not supported.

And for a LZW31 and an Aux:

image

Doesn’t the LZW31 require a Neutral when used with a dumb 3-way? I was under the impression the only time a 3-way that worked without a neutral was with an Aux switch.

I think you might be correct. But now that you’ve stated it I can see even if the dimmer could steal power through the load, when it “switched” from the “load” connected output to the light to the “traveler” connected to the light it would loose power.
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Just thinking out loud, I wonder if a bypass from the “Line” to the “Traveler” make it work? Folks, do not try this at home we’re trained professionals who have no idea what other issues this could bring up :slight_smile:

Yep. It’s documented by Inovelli here:

If you DO NOT HAVE A NEUTRAL here are the limitations:

3-Way or Multi-Switch Installation: You can only install this switch in a multi-switch setup with an auxiliary switch such as GE’s or HomeSeer’s and you will not be able to use another smart switch or dumb (existing) switch.

Although our switches can support a non-neutral setup I still recommend a electrician to run the neutral. This is for safety and it also brings up the old wiring to NEC/CE code.

And your homeowners insurance company will love you for that !

here is how to wire a 3-way light switch

Can anyone help me understand what I’m not getting right.

Box A HAS two switches. Both 3 way for different things one for stairs and one for dining room.

Box a has 2 live wires coming in.

Box B is 3 wire romex red black and white that run to box a.
The black wire in box b is hooked up to the common on switch but when I trace wire back to box a I see that the black wire has been capped and connected to the live wire that feeds my stair switch in box a.

I’m trying to install a sonoff mini l

I have it alarmist working but when I flip switch in box b to one position I loose power in box an after a couple seconds