Can I replace a three way switch with a smart switch in a Four Way switch setup

Devices & Integrations
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Hi There, I’ve been replacing a lot of switches in my house with smart switches both single and double pole setups.

I however have an issue that I wanted to get some feedback on. Our kitchen has four switches that operate the same pendant lights that hang from the ceiling. I found the one four way switch and the others are three way switches. My question is can I replace one of the three way switches with a smart switch for home automation?

I’d leave the four way in place and only wire in one smart switch. The wiring looks the same as the other three way switch i replaced.

Thanks in advance for the help.

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It will depend on the exact brand and model. With most brands, including GE, you will have to replace all of them with smart switches. However, as @Automated_House and @ritchierich noted below, there are two specific brands, the zooz and inovelli, which may let you use the existing dumb switches depending on the exact wiring.

Smart switches are not wired the same way dumb switches are in these kind of configurations. When you have dumb switches, the current is shifted from one loop to another when you flip the switch. Like switching track patterns on a model railroad layout.

With smart switches, the master switch at least has to always have power so that its radio can hear the next “on“ command. So the wiring is done differently.

People in the following thread can answer more specific questions:

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If you’re line and load are in the same box, you can also use a Zooz or Innovelli switch and not have to buy $20 add on switches for the other boxes

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@JDRoberts with the Zooz and Inovelli smart switches you don’t have to replace all the switches. Right now they require line and load in the same box but I have read they both are releasing a new switch that doesn’t require this. But all of this said you may need to change some of the wiring in the boxes to make the dumb switches work.

Now all of this said the Zooz and Inovelli work great for on/off switches but if a dimmer is preferred that is where I personally prefer the GE/Honeywell/Jasco products since the Aux switches can also control dim levels on the master switch. I thought I read Inovelli is working on an Aux switch offering too.

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Michael, as Jimmy and I have mentioned Zooz and Inovelli make smart switches that don’t require you to replace every switch. Are these pendant lights currently in a dimmer? If so do you want the ability to control them from all locations? If so then you would need to replace all switches having one master and 2 Aux.

But if you require a simple on/off switch you need to confirm where your line and load are in the same box. To do this

  • Open the boxes of your 3way switches (ones with 3 wires).
  • While the switch is off, measure the voltage on the common screw of both switches. One will have power and the other will not.
  • Unscrew the dumb switch that has power and follow the 3 wires hooked up to it.
  • if they are all part of the same 14-3 Romex wire then you don’t have load in this box and it’s most likely in your other 3way switch box.

Happy to look at clear pictures of the box to help as well.

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Thanks all!

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@JDRoberts
I know this is an older thread but I have a similar question…
I just realized I have a 3rd switch that controls a set of LED living room lights. I planned to install the 2 3 way switchs (TP Link Kasa 3 ways) in the LR and now i’m wondering what I need to do with this 3rd switch in the hallway. Do I need to install another a 3 way switch on there or will the 2 suffice?
Thanks
Cyn

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I ended up just putting one Kasa three way switch and it works. I did NOT have to replace all three.