I am trying to install a Kasa smart switch and ran into what looks like a ground wire that just passes through the switch(see image below). This switch is one of two that control a single bank of lights.

  • Is this in fact the ground wire?
  • What style of wiring is this?(do I need more information to be able to tell?)
  • Is this bad practice to pass a wire through this way?

Going to probably let an electrician sort this for me since I’m out of my depths, but want to know more.

 1 of 2 switches that control a single bank of lights

other angles

Temp until I can get a better picture

  • Can you post a photo that looks into the back of the box please? – ThreePhaseEel Jan 23 at 19:21
  • @ThreePhaseEel I added a photo of the other side. let me know if this is good enough, otherwise I will have to open the switch again later today. – user3613062 Jan 23 at 19:29
  • We'll need a photo looking much more squarely into the back of the box to find your neutral – ThreePhaseEel Jan 23 at 19:37
  • Also, which model of Kasa switch are you wanting to install here? – ThreePhaseEel Jan 23 at 19:40
  • I see a green screw on the left side of the drawing that has nothing attached to it. Nor would I expect any since this is a metal box. However, this appears to be a 3-way switch in conduit, note 2 yellow travelers on brass screws, and a black feeder+onward on the black screw. Normal 3-way wiring. – Harper - Reinstate Monica Jan 23 at 20:53

That's a hot, not a ground

What you're seeing is an always-hot wire most likely, not a ground, that lands on the terminal screw then continues onward somewhere else in the circuit; some electricians will cut the wire and pigtail, others will use both terminals in a screw-and-clamp, and yet others will wrap a stripped section mid-wire around the screw as you see here. The 3-way Kasas, fortunately, have terminal screws, so you can leave it "as is", or pigtail it; if you were using a switch with a wire pigtail built-in instead, you'd have to cut and strip so that you could nut the pigtail to the cut ends.

Good news: this is a conduit job

The yellow wires and the use of a metal box with a mudring also tell me that this is a conduit job, which is good news: it not only means that you likely have metal conduit providing your grounding path, it means that even if there's not a neutral already in this box, pulling a neutral to this box is an easy job for any electrician. It also means that you don't need a grounding wire for the switch; instead, it simply can pick up ground via its mounting screws.

Good news #2: neutral appears to be present

The other good news is that since this is a conduit job, we know that white wires must be neutral in order to meet Code. So, we know offhand that those two bundled white wires must be a neutral bundle. However, since one conduit may have multiple circuits in it, we'll need to know more about the inside of the box in order to figure out if it's the correct neutral for you to connect to.

Bad news: this is a 3-way

The bad news about that pair of yellow wires connected to separate switch terminals, though, is that they tell us this is one end of a 3-way switch arrangement. This means that you'll need the 3-way version of the Kasa smart switch, part number HS210, instead of a single pole switch, and will need to find the other 3-way in the complex so that you can replace it as well.

  • It does look like there's a neutral with a yellow wire nut on the side of the box. Harper will be delighted to see the yellow travelers.. +1 – JACK Jan 23 at 19:54
  • Thank you! I definitely have the wrong Kasa switch(HS200P3)😞. This is a good learning experience though! – user3613062 Jan 23 at 19:55
  • @JACK -- it's definitely a neutral, we just don't know if it belongs to the right circuit – ThreePhaseEel Jan 23 at 19:55
  • @ThreePhaseEel Right! I didn't see that third picture. – JACK Jan 23 at 19:58

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