Seeking Help with GE Z-wave 3-way Wiring Troubleshooting

Hi, and thanks for taking the time to look at my post.

I am trying to install a GE Z-Wave 12729 Dimmer and 12728 Add-on in a 3 way to control a circuit that contains 7 recessed cans with LED lights.

This circuit is currently controlled by 2 dumb 3-way switches.

Pictures of both boxes and all box wiring:

Dumb switch wiring:
Main box: 120V line to common terminal, 1 red traveler, and 1 white wire to the opposing terminals on the dumb 3-way switch.
Secondary box: Red and White from the main box (conductivity tested with a 9V battery). 1 black to the common terminal.

Unlike several other successful GE 3-way installs in my house (including another one in the same main box), the main box does not currently have a Load connection for the 12729 and I’m unsure how to wire the smart switches as a result.

However, I do note that there are 2 black wires tied together in the main box.

Hopefully, the pictures are worth more than the text of my post and someone out there recognizes this wiring layout. If I knew what this layout were called, I could search here more effectively, but I did read the 3-way FAQ and search before posting.

Thanks and please let me know if there is any other diagnostic info I can provide.

[Edit] Thanks everyone: it was line and load in same box and easily resolved by Michael’s suggestion and made perfectly clear by Ryan’s diagram.

Daniel, thanks for calling attention to the neutrals. With that concern highlighted, I think this diagram from the FAQ makes perfect sense:

Disconnect these wires and verify that one of these goes to the black common terminal of the secondary box. If so your main box has both load and line and the other black wire is your load. What I suspect is happening is the load is being sent to the secondary switch since 3 ways require line on one side of a 3 way and load on the other common screws.

If my assumption is correct, in the main box put a wire nut on the black wire going to the secondary and secondary box put a wire nut on the black wire from the main box.

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Here’s a great diagram. Now, this uses 2 add-on switches. But the same hold true for one.

And the neutrals do not necessarily all need to be tired together like in this drawing. As long as there’s a Neutral bundle, you can tie into it.

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Wrong. Neutrals are already tied together at the breaker box, but for safety reasons and as per NEC and fire code a load is associated with a Line/Neutral pair. So for a load you use the line from a breaker with its associated neutral in the same cable. Do not use a neutral that’s on different cable or you stand a good chance to exceed current through the wire and start a fire.
Also, unless you have good to perfect wiring in the house you could have a floating voltage between two neutrals.


I would assume that would have already been taken into consideration when the dumb switches were wired. What I meant was that they wouldn’t need to re-wire the neutrals together because if they’re already on the same breaker, then they already are together.