Need Help With GE Smart Switch w/Z-Wave Plus Wiring

I have been lurking and learning as much as I can for quite a while… this is my first time reaching out for help/posting, so please forgive me if I have posted to the wrong area… I can assure you that I didn’t do so intentionally.
Having recently retired from 30 years military service, I now finally have time to explore a little world of smart home automation… Empowered by all the amazing ideas/info exchanged between individuals here in the SmartThings community, I have been successful in implementing many SmartThings devices and lighting automations thus far, but have run into a problem yesterday when I installed my first two set of 3-way GE smart switches… with add-on switches.
I watch the videos/read everything I could and the first set of smart switches that I installed in my garage went smoothly… Just when I thought I had it all figured out, my attempt to install another my second GE Smart Switchto control my outside flood lights… I’m now CLUELESS as to how to proceed/properly wire without destroying the new Switches.
I have 2 sets of flood lights on the back side of my house controlled by 3-way switches… one of the 2 switches located downstairs… The other in the master bedroom… both lights function properly before beginning this task…
How to determine which switch is the line switch and which is considered the load switch… the indication I’m getting from my understanding of the videos is that both appear to be fed from the service panel.
Yesterday’s installation with power on and both switches in the off position as instructed, there was clearly only power being supplied to one of the two common terminals…
Today, with power on and both switches in the off position using multimeter to check for voltage on the common terminal… (here’s where the problem begins) with both switches in the down position/off there is 120 volts on the common terminal of BOTH switches… Grasping at straws, I thought possibly one of the switches had failed even though the system was working fine before I started, so I shut the power and did continuity checks of both switches… and was able to verifiy that both are internally working properly…
Downstairs location: Double Gang Box with 3-way switch that I’m attempt to replace with Smart switch and standard single pole for porch light. The common terminal on a 3-way switch also jumpered and feeds the single pole switch for the porch light. There’s a total of four wire runs entering the double Gang Box… (1) three-way run for travelers (black, white, red and ground) other three runs are two-way (black/white/ground) and all four runs enter through the top of the double gang box. I was reading in one of the post where the Line Feed usually enters the Box through the bottom. All 4 neutral wires are wire tied/capped together.
Upstairs master bedroom location: single box, 3-way switch… Three runs all entering the Box through the top… (2) two-way runs, and (1) three-way run. All three neutral wires are tied/wire cap together.
I viewed very informative post that had the nine different 3-way wiring scenarios none of them seemed (at least in my mind) to apply… although I might be missing something just prior to my retirement I was involved in serious accident and ended up with a TBI, so I might be overlooking the obvious.
I started wondering if my power source was wired to the light fixture itself, but when I looked at those examples… it appeared as if the neutrals were Not tied together, or neutral was being used as hot wire and neither of those scenarios are applicable in my wiring configuration.
I would be EXTREMELY GRATEFUL for any and all help!! The last thing I want to do is needlessly destroy the new smart switches, or worse burn the house down… I’ve already been there and done that several different time in different applications since my accident.
I’m sorry the post is so long just wanted to make sure that I gave ample information to aid in the troubleshooting.


Thank you for your service. And welcome to the crazy world of home automation! You will definitely find a lot to keep you busy here. :sunglasses:

Hopefully @Navat604 , @jhamstead , or one of the other wiring experts will be along soon to help you.

Meanwhile, I did want to mention that if you live near a Home Depot, many have a free course on installing three way switches which can help get you comfortable with tracing the circuits and using the tools. The class itself won’t cover smart switches, but since Home Depot doesn’t sell the GE smart switches, sometimes instructor will help get answers for you. In any case, they are worth checking out. :sunglasses:

Also, it’s always a good idea to take “before“ photos of the wiring, including the back of the original switch showing exactly where the wires connect. I’m sure the wiring experts will want to see those, so you might as well go ahead and take them now. :wink:

Take a look at the edited quote and insure it’s correct. It will help if you can post pictures of the two boxes. With the original switches wired correctly, pull them out so that we can clearly see what you have.

It sounds as if you have neutrals in both boxes, so that’s good. Chances are power is being fed to one of the boxes, so that’s good too.

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Hi JDRoberts,
That’s GREAT advice… I do live near Home Depot and will look into attending their classes after the holidays!
As for my current situation, fortunately I didn’t cut anything loose… it’s still configured as it was, I merely pulled the switches back from the wall far enough out to test with multimeter and view the wire situation coming into both boxes…
I’ll gladly remove the switch plate covers and take pictures if need be… however the wiring inside is standard… Black hotwire on the common (black screw) and travelers are on the gold terminals… I think it’s just a matter of figuring out which box is line feed so the master smart switch can be installed in that location and the add-on in the other. Testing it with both switches in the off position… power on I get indication that both are being are HOT/fed from the service panel… which makes no sense to me.
I’ll Also take your advice and in the future capture picture of wiring prior to reconfiguring anything… I should have already been in the mindset to do just that.

Thanks again for your advice hope you enjoy a wonderful holiday season!!

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There is no “off” for a three-way switch. A three was switch toggles back and forth between connecting the common terminal and one of the two traveler terminals. So when you say both switches are in the “off” position, do you mean that both are thrown so that the outside lights are turned off, or do you mean that both switches are simply in the “down” position?

If both commons are hot, then the outside lights should be on.

Hi Bry
I read your quote carefully… and that is exactly what I was trying to convey, so thank you for taking the time to claiify/help me out! Not so long ago I use to be pretty sharp… Not so much anymore post accident/head injury, but it could have all ending much worse, so I consider myself lucky.
Hope you enjoy your weekend!

I meant that both switches were in the down position… Working with limited knowledge… I got that procedure from one of the main GE Smart Switch installation video where the gentleman is testing for the line and load switch with a multimeter…
Looking at it logically, I see where you’re coming from… There is no off position… so maybe my real question should be how do I properly test both switches to know which box is the line switch fed from the service panel and which is the load?
I’m not sure if this helps, but I just put both switches in the down position again a few minutes ago and when doing so, both flood lights were on/burning brightly.
Not sure if this matters, but there are two sets of flood lights both sets individually configured with two lights bulbs

So I’d expect both commons to be hot if the lights are on, that’s normal.

The best thing for evaluation will be the pictures. There are a number of people here pretty knowledgeable. Once we see the pictures we can guide you on further testing.

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As Bry said, 3way switches don’t have off/on. instead, they switch between the two travelers.

assuming only 2 switches wired properly…
When the lights are on, the switches have selected the same traveler and current is flowing from line (common on switch1) through one traveler to the load (common on switch2). When the lights are off, current is flowing from line through one traveler that is not switched to the load.

Hi TonyFleisher,
Please help me understand… are you saying that I should change the position of the Travelers? It’s quite possible they got mixed up at some point if that’s what you’re saying because shortly after I moved in I removed the standard construction grade 3-way switches and put in the decorative lighted paddle switches… I was under the impression it didn’t matter what position the Travelers were in as long as they were on the gold terminals, but if that’s not the case please advise.

Thank-you! I will take some pictures and try to post this evening after dinner… hopefully I can figure out how and where it’s upload the photos

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No, traveler doesn’t matter… unless you expect the lights to be off when both switches are in the same position.

To find the line, you need the light to be off. The position of the switches isn’t what is important. The usually recommended method is to disconnect both switches (turn breaker off before disconnecting) and then find the line that has your main current.

As long as the photos are on the same device that you are using to create the reply, you can just paste them inline using the “photo” Icon on the reply box.

Here’s the link to the lower-level double gang box that contains the three-way switch that operates the flood lights with a single pull jumper off to supply common on switch for porch light

This is the link to the single box with a three-way switch that controls my outside flood lights

If for some reason the Google links don’t, work please let me know and I will upload using the picture icon as instructed…

Hi TonyFleisher
I Haven’t got a chance to read the other posts yet… I was busy trying to upload the PHOTOS.
After reading your latest, you may have already solved the problem… I was doing as I thought was right from the video I watched and was putting both switches in the down position and then checking for voltage on the common terminal of both switches… as I learned an hour ago when both of my switches are in the down position my flood lights are on

If I’m understanding you correctly you’re saying the position of the switch itself matters not, but rather the light itself needs to be in the off position and then check for voltage on the common terminal…
Is this correct?

Just put the three-way switches in position to turn the light off… One up… and one down and now I’m seeing what I think I should be seen… my downstairs common terminal is energized 120 volts and the upstairs switch common terminal does not have power…
If that’s the case, then I can definitely proceed from here I do remember how to install the switches properly from yesterday… like I said I was just clueless as to know which switch was the line switch in which was the load switch… but I think you just solve that for me

You are on the right track. I mentioned many times before. The common screw terminals are key to 3 ways circuit. Just remember the common terminal of one switch is power from the circuit breaker and the common terminal of the other switch will be the power going to your light bulb.
I usually use the ground terminal for one of my voltmeter test lead when I don’t know my neutral. This way you won’t have strange voltage reading when on wrong neutral reference.

After learning that it’s NOTthe position of the switch… Like the guy GE smart smart switch installation video conveyed… I learned today and will never forget is that it is about whether or not the lights are illuminated when checking to see which switch is the LINE switch vs LOAD switch.
After being given that direction, I ran down stairs like a little kid at Christmas… checked for voltage on a common terminal on both switches and low and behold, the switch I originally suspected downstairs was the home run from the service panel… no voltage upstairs…With the install still fresh in my mind from yesterday, I was able to get both switches installed in about 30 minutes or less… Confident with the help that I received from you guys… I buttoned and everything up and turn power back on and it works perfectly…
Can’t tell you how grateful I am for the help!!! I spent the majority of my day trying to resolve this issue to no avail… With GE Smart Switch technical assistance being closed over the weekend, I would have let this issue ruin my whole weekend.
My sincere thank-you to one and all!!!


Glad you got it going!

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