4-way, partial neutral (one box) and line/load in separate boxes

Good day,

I have a setup that I’d love advice how to connect the best way. It’s a 4-way setup with a partial neutral. I have both aux and 2-1 blues available to work with. The 4-way controls two ceiling light fixtures.

Box 1: Line, and two conductors (red/white)
Box 2: Traveler box; 4 conductors (2 red, 2 white) and a black-nutted pair.
Box 3: Load, neutral bundle (nutted), 2 travelers (red/white) and a black-nutted pair.

I can’t do an all-smart in this setup, correct? Not enough conductors to get neutral back to the line box. Do I simply ignore the neutrals that are available and do the non-neutral setup?

Any advice is appreciated!

P.S. I’d love to retain dimming ability.

I believe I see it now. My Box 3, I need to split the ‘actual’ line (the black nutted pair) and otherwise use the 4-way neutral diagram.

I would appreciate confirmation. =)

So there is something irregular in the wiring you’ve described. It’s easily fixable. I’ll describe what is likely incorrect so you can adapt when you install the smart switches.

In a normal line in one box, load in the other 4-way, you have an incoming 2-wire hot/neutral in one box and a 2-wire load going to the light in the box on the other end. In between the boxes are 3-wires and all three conductors are used.

Wired properly and starting at the line box, the black hot from the 2-wire should be wired to the switch and the neutral should be wired to the white on the 3-wire. This is so the neutral from the proper branch circuit can be passed along and end at the light. In your case, however, doesn’t sound as if this is being done, since only 2 or the 3 conductors in the 3-wires are being used.

At the load box, you describe that the neutral being sent up to the light is provided by a neutral bundle in the load box. The problem with this is there is a pretty good probablility that the neutral in the load box doesn’t belong to the same branch circuit as the hot in the box at the other end. Using a neutral from a different branch circuit can pose a significant safety issue and is prohibited by code for that reason.

When you are working in that load box, use caution as there may be more than one circuit in that box, meaning you need to flip more than one breaker. Use a non-contact voltage tester.

To fix this with the existing dumb switches, at the line box use the white to send the neutral to the load box, rewiring to use the black and red as travelers. At the load box, remove the neutral going to the load from the bundle and use the neutral being passed from the line box.

For the smart switches, the Inovelli would go in the load box with Aux or dumb in the other two, following the standard line/load wiring diagram.

If there is a hot/neutral in the load box, possibly from a different circuit than what’s being used presently, you can probably put the Inovelli in there as well if it’s more convenient. That would be a line/load same box.

Thanks, @Bry, I appreciate the quick response!

Please correct me if I’m wrong, but what I ended up doing was the nutted black pair in the load box (Box 3) was the actual line coming into the circuit. I think it was passed along to Box 1, which is why I originally called it line. After pulling apart the pair in Box 3 and re-testing, I determined it was 120 (and the previous line in Box 1 was dead).

There’s also only one circuit in all three boxes, so my neutral was intended for this circuit.

After that I wired it as per the diagram and it set up properly. The additional aux switches function as intended.

I read through a bunch of posts looking for this scenario and although it’s probably been posted before I thought it a good learning opportunity. If your line wire appears to be in a different box than the neutral, it’s most likely just passed through and you need to break up your black nutted pair to end up with neutral and line in the same box.

Does that sound right?

Thanks again.

So it sounds like you have a line/load in the same box, so you put the Inovelli there and wired Aux’s in the other two boxes. It’ all working. So that sounds ok to me.

What you described about the previous wiring makes sense now that you know the line did not originate in that box. That is the proper way of wiring a line/load same box multi-way. You start at the line/load box and send the hot (only) to the far box where it is returned SWITCHED and the up to the light. So yep, that sounds proper to me now that you’ve identified the proper configuration!

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With the new proposed wiring, you absolutely can have an all smart switch setup. Just need to send hot and neutral to each switch and associate the switches.


Although I ended up using two of the aux and one smart, if only to save money. Other than the missing LED, so far I don’t see any downsides.

But I’m definitely a converted fan of the Inovellis. Previously I was using TP-Link Kasa and I’m wishing that I did all Inovellis.

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