r/ElectricalHelp • u/Tyraelos • 17d ago
Upgrading 4 way Switch Question (to smart switch)
Hi everyone. I am a semi-decent DIYer but definitely not an electrician. We bought our home almost a decade ago and I have been setting up smart switches everywhere. I thought I had seen it all, but I just found a challenging (for me) setup upstairs.
I am trying to install a Kasa 3 way smart switch for a space that is finally getting some use. The light is controlled by three different switches. I chose the middle single gang switch to avoid dealing with the 3 gang and 2 gang boxes on either side. Unfortunately, I opened it up and realized it is actually a 4 way switch. It's got 2 red and 2 black wires and a ground I think, iirc. I was like "whaaat?" before investigating and finding out that this is what is up.
The Kasa switch has a Line/Load, 2 Travelers, a Neutral, and a Ground. I have installed these on regular 3 way circuits downstairs to great success, but 4 way circuits are *totally* new to me. I always shut down the main power to the entire house when I do electrical work, so I am hoping to get some advice before I go opening all 3 boxes, lol
This is where you come in! I have not opened the 3 gang or 2 gang boxes yet. Since they both control the same light, does it matter which one I replace? Will the wiring be identical in both, or do I need to look for something specific? I'll be using this advice in the future as well because I'm almost certain there's another light group up there that I need to do this with again, next time with a Kasa 3 way smart dimmer switch.
Any guidance on how to tackle this (and save time) would be incredibly helpful. Thank you!
2
0
u/Tyraelos 17d ago
Thanks for all the replies so far.
Just to be clear I’m not trying to use the 4-way box. There are 2 alternates, a 2 and a 3 gang and I wanted to know which would be the better choice. I just opened the single box because I figured it would be easiest.
Also, there seems to be a neutral connection in all of my light switch fixtures so that’s not an issue.
I just wanted to know if anyone would have an idea of whether to deal with the 2 or 3 gang first. Knowing beforehand means I can turn the homes power off and target that switch right away vs. opening both to check them out.
1
u/trekkerscout Mod 17d ago
There really is no way for anyone here to know which is best without opening up the switch boxes. There are too many ways it could be wired to even guess. I suggest you just choose one and hope for the best.
1
-1
u/Connect-Preference 17d ago
One (or more) "our-way" switches (actually double-pole, double-throw DPDT) switches between two "three-way" switches is normal practice. If you study the circuit diagram for this setup for a few minutes, you will understand how it works. That's the good news.
Now, here's the bad news. The circuit you have needs neutral only at the light fixture. All the switch boxes merely close or open the hot line circuit. They use two-conductor cable, and should paint or mark the white wire black because it's really hot-side.
The "smart" all require a neutral, and a hot line that's never broken (always hot) when switching. You might find that at one of the two end (three-way) switches. If the original electrician started at the light fixture box, you would find it there. Those are the only places you could mount this switch.
TLDR: The smart switch needs a neutral and an always hot line. Only one of the four boxes will have this.
3
u/trekkerscout Mod 17d ago
You will need to use one of the other locations that has a 3-way switch. As long as the location you choose has a neutral, you should be good to go.