Identifying light switch wires when colors don't match


Old 12-18-20, 10:25 AM
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Question Identifying light switch wires when colors don't match

Hello, this is my first visit to this site and I'm hoping someone can help me. I do moderate home repair projects but I'm always leary with electrical work. I'm trying to replace some standard light switches with wi-fi smart switches. The new switches say they require a neutral wire. My house was built in 2010 so I'm assuming they would have been required (I live in Chicago).

So after removing the cover plate, I see 2 red wires connected to the same screw and one black wire connected on the same side but in a separate position. On the reverse side of the switch I see 2 screws to which nothing is attached.

Now on the new Smart Switch there are four wires: one red, one black, one white and one green. Which ones get attached to the existing wires?? I am attaching pictures of both switches along with the diagram from the installation instructions from the mfg of how the connections should be made.

I can certainly use some guidance here. Thank you!

Wire connections on existing switch.

Opposite side of existing switch. two screws with nothing attached.

Wires on new smart switch. They are labeled: red=load, black=line, white=neutral, green=ground.

Mfg's installation diagram.
Old 12-18-20, 10:53 AM
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Colors can sometimes be misleading, so it's more important to see where they go rather than the actual color.

The red wire looped over the screw is likely your always-on 'hot' wire. It probably goes to the neighboring switch to provide power to the light you're working on as well as whatever's connected to the other switch.

While the loop over the switch is a code-compliant wiring method, it makes your work a bit harder, You'll need to either cut or splice that wire so you can use a wire nut to connect the black lead from your new switch. There are a few ways to do it, but in the end, that wire needs to be connected to the black of your new switch and the screw in the other switch.

As for neutral, there's probably a couple white wires stuffed in the back of the box all nutted together, that'll be your neutral to connect the white wire from your new switch.

Same with ground for your new switch - to the bundle of bare wires.

I think my guess is a good one - but we'll know for sure if you can take a picture including all the cables coming into the box and where they go.

Last note - the reason your old switch has an 'extra' unused screw is that they used a 3-way switch. No issue with doing that, but it's a useless terminal how it's being used. So you can just ignore it.
Old 12-18-20, 01:40 PM
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Someone used a three way switch for a normal switch. No problem there. You use the black and red as you power and load wires.
The green is ground. It connects to the box. There should be a screw in the bottom to put it under.
The white needs to connect to the neutrals. Being in Chicago you have conduit. It is possible there is no white wire in the box. If no white wire you will need to feed one though the conduit. With conduit neutrals are not required since you can add one if needed at any time.
Old 12-18-20, 03:40 PM
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Thanks guys. I had to take my dog to the vet so I will analyze the setup better tomorrow and and give it a try.

And in response to Zorfdt's comment as to "what's the worse that could happen?" Well, if I don't spark an electrical fire when I turn the circuit breaker back on, I figure I could be telling Alexa to "shut off the light" and the Roomba would start vacuuming! (only kidding, the IT part I have no problem with. I currently have 24 wi-fi enabled "smart devices" running.

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