Wiring a GE In-Wall Dimmer Switch - Help Needed

I’m trying to install a GE EZ Smart (Jasco) in-wall dimmer switch to replace a dumb dimmer. This is a 3-way installation, and I can’t make heads or tails out of the existing wiring. The existing dimmer has three wires: red, black, and red with white stripes. I’m assuming the red and white striped wire is the ‘traveller’ wire and the other two are the load wires.

There are four romex cables coming into this outlet box. Three of them are two wire (black and white) and one is a three wire (black, white, and red).

The GE dimmer requires neutral, but I’m not sure how to identify which of the wires in the outlet box to connect to the neutral terminal on the dimmer. Any help would be appreciated.

Here’s a crude diagram of the existing dimmer connections and how all of the cables in the outlet are connected:

Have you had a chance to look at the GE wiring FAQ yet? It should help.

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Don’t assume, get a multimeter! (And read that post JD linked to, it’s very helpful)


What @marktheknife said. :sunglasses:

With the exception of the ground wire, residential wire colors are not mandated by US code in most situations, and people can and do use any color for anything, sometimes just depending on what they have in the toolbox in that particular day.

You need to map every circuit of every switch so you know exactly what’s going on.

By the way, if you live near a Home Depot, most of them will have a free class on how to install a light switch which you can take. They won’t cover smart switches, but you’ll learn a lot about wiring and the tools that you use. And since the GE switches are sold by Home Depot, the instructor can often get you an answer if you have a specific question on those. But in any case, just the basic class can help a lot.


This one has a better explenation:

Take those good advices from the 3 gents above because they will save you some hair and insanity. Since you provided only one rough scretch of the 3 ways and missing some details.
I will have a wild guess just incase you couldn’t find the right wiring. That drawing has some non standard wiring.
The white and red of romex 1 are your travelers.
The black of romex 1 is your load but only if it connected to a common screw terminal (dark color terminal) of your other switch.
Romex 4 is your romex from the circuit breaker so white is neutral and black is line.
The odd one are romex 2 and 3. These are your wiring coming from your light fixtures. You must have multiple lights on the ceiling and it’s probably easier for the electrician to run it this way.
To confirm. Put your meter on neutral(white on romex 4) and black (romex 1,2 or 3). You will get 110v when the lights are on and 0v when off.

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I have a multimeter. For those of us who are not electricians, can you summarize what to look for? What kinds of voltages should I be seeing on each of the lines coming into a box with a dimmer? What do I reference the voltages to? The bare wire?

Not an electrician!

But I’ve tried to learn as much as I can about the wiring in my home by discussing with pros here like Ray, reading other sources and testing things out with my multimeter.

Here’s how I would confirm that romex bundle 4 is in fact going to your circuit breaker.

Start by turning your breaker off and disconnect the wires in romex 4. Then turn the breaker on.

Start by putting your multimeter to black and white (carefully!), it should read 110V all the time. Then put one terminal on your ground wire and recheck voltage with the other terminal on black then white. If black is hot, it’ll stay 110V; if white is neutral then it’ll go to 0V (there’s no voltage difference between ground and neutral).

Ray is far more qualified than me to ID the other bundles, so I’d suggest following his advice in the post above.