Hello SmartThings Community
Wondering if I can get some help, I have 3 existing dimmers 1 Lutron Master dimmer and 2 Slaves. I’ve purchased the equivalent 2 x GE 127232 (Add-On Rocker Zwave) and 1 x GE 127242 (Dimmer) to hopefully switch these lights over to Z-Wave (some of the last remaining ones in my house).
(edit- see below)
If you’ve read other similar project posts, you’ve seen me say before that US code does not mandate any particular wire colors. People can and do use any color for anything, sometimes just because it’s the end of the day and there’s only one roll of wire left in the toolbox. So before you do anything else, you must test every segment of every circuit to see what it actually does. You can’t go by “looks like.”
You didn’t give the model numbers for your Lutron devices, but many of them do not require a neutral for the master. So you may not have one there. But the only way to know for sure is to test the circuits, and you need to know for sure before you start wiring new devices in place.
If you don’t know how to do this testing, you need to either bring in an electrician or get more education. If you live near a Home Depot, many offer classes in how to wire a light switch. They won’t usually cover network switches but at least you’ll learn how to test the lines and identify exactly what you have now . And since the GE switches are sold at Home Depot, the instructor can often help you figure that out as well.
Your first/master pic sure looks like it has a neutral. What is making you think it doesn’t? Also, one or more of the black wires may be travelers as well. Like @JDRoberts said, make sue you test them all and know what each does before connecting up the new switches.
If it’s using a physical traveler, there aren’t enough wires. Hot, Load, Ground, Neutral, Traveler.
Of course, there are many different ways to wire a three-way. In some, the load is wired from an auxiliary, not the master.
Or maybe there isn’t a physical traveler.
But the only way to know is to test every segment of every circuit. 
solution below! Thx all
The lights work through SmartThings because the master works. The GE auxiliaries are always invisible to SmartThings because they do not have zwave radios. They work by sending a pulse message over the physical traveler wire to the GE master.
Most likely the wiring configuration is one in which the auxiliaries are both run off the same loop rather than each connecting to the master and that’s throwing things off. You need to follow a wiring diagram for the GE devices, you probably won’t be able to use the existing wiring pattern.
Also, I may be misremembering on this, @Navat604 might know, but I seem to remember that with the GE switches they all have to run off of the same neutral. That might not be true though, you’d need to check the user guide.
Are both travelers connected to the middle aux switch?
You master switch will be at location 2 or location 3 but I couldn’t make out of how many wires you have with picture number 3.
If you have 2 black, 2 white and one red then your neutral is at the light fixture box which will not work with your GE switches.
If you have 3 black, 3 white and 1 red then your load and line hot is there and you can have your master at this location or at location 2.
"The Neutral is from a separate circuit - but aren’t all of these connected on the Neutral Bus in the breaker box?"
They are all connected to the same bus at the breaker but that’s not how home AC neutral circuit is suppose to be used. I replied to a couple of posts about this and there is a chance your circuit could be overload if your 2 loads are at the same phase breaker. You can only share neutral with different phase loads and even that’s probably not up to code in many places other than kitchen plugs.
@JDRoberts, the add on switches will definitely have to be on the same Traveler wire but doesn’t have to be on the same neutral.
Thanks for the information!
Another case in which shared neutrals are a no-no is in the case of an AFCI circuit, which you will find in new builds. In this case the neutral does not go to the bus, it goes to the breaker first, and the AFCI breaker has a pigtail that goes to the bus. This complicates the installation of smart switches, as you need to ensure that your switch is on the same neutral as your load, or else your AFCI breaker will trip.
Off the top of my head - but don’t GFCI in the breaker boxes do this also?
AFCI and CFCI will be an issue for sure since the power out from line hot will no longer equal to power return from neutral. I encountered an issue where people tapped one leg from a 220v CFCI circuit (no neutral) and use the neutral from another circuit. The owner insisted he didn’t do anything to cause the trip. It was an outside light he installed 2 weeks before that was tested fine that time.