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I'm in the process of replacing old electrical outlets and switches to more modern Decora type outlets. I've done a few so far with no problem, however, this one has a different configuration that's got me stumped.

I've attached a few images. The duplex outlet is switched and there are the normal 2 black and 2 white wires plus a ground wire. But as you can see in the photos, there is one black and one white wire attached on the same side of the receptacle, not the normal 2-black-on-one-side-and-2-white-on-the-other-side configuration. Also, the B&W wires that are next to each other on the receptacle are twisted together from different strands farther back in the box shown in the picture.

How would I wire this to a standard 15A outlet with 2 screws on each side? I know that I need to break the tab on the new outlet and black goes to brass, and white goes to the silver screws - I'm just confused at the B&W wires on the same side of the outlet.

I've also attached a picture of the breaker box. The one breaker switch that's turned off is the one powering the outlet in question. All blue breaker switches are 15A and this is a blue breaker BUT it's got an orange tape on it. Another orange tape is marked to a 20A breaker. (An electrician must have done this some years ago when I had a kitchen remodel).

How do I interpret this marker on the breakers?

BTW, this particular receptacle was never touched during the remodel.

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    No way to guess what the orange tape means. Only the person who put it there would know. Dec 10, 2020 at 17:51
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    Unless you can see the remainders of writing on that tape, it's of no value now, I would think. That's masking tape, so someone was probably just marking breakers for quick reference when working on it.
    – FreeMan
    Dec 10, 2020 at 18:03
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    Upon closer inspection, I'd say it's a very good thing you're replacing this outlet. The "lone" black wire is stabbed into a connector that looks like its plastic has been broken or melted away. In either case, that's a good location for arcing to start a fire in your house.
    – FreeMan
    Dec 10, 2020 at 18:31

3 Answers 3

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What's going on here?

The switched outlet is controlled by an old-style switch loop.

A "switch loop" is a spur line that goes to the switch (and nothing else). It has 2 wires: always-hot, and switched-hot. As you can guess, switched-hot is hot when you want the lamp to be on.

Today switch loops must be /3 cable, and you use black for always-hot and red for switched-hot, which works out pretty nice. Historically, switch loops used /2 cable. When you do that, Code requires you use the white wire for always-hot. That is to make it more obvious that it has been re-tasked to be a hot wire.

However, Code also requires that a white wire used this way be re-marked by wrapping it with black tape (or other methods). That wasn't always required.

That means the black wire is the switched-hot.

To aid newcomers, I strongly recommend obtaining both black and colored electrical tape (also some wire nuts and pigtails should be part of your personal "kit"). You must mark the white wire with black tape. I also advise marking the black wire with red tape, so it is more clear what is going on. I'm not saying this because you're novice; I do it. Some of my work is very complex and without color coding, it'd take me 20 minutes to figure it out every time!

enter image description here

Isn't that better? Black to (remarked) black, easy peasy.

"Why don't I just remark the white wire red and switch their roles?" Because Code says otherwise.

Now it's just down to "how do I put 2 wires on one screw".

The simplest way is to get the $3.00 spec-grade outlets that accommodate "screw-and-clamp" to accept 2 wires in a clamped back-wire underneath each screw.

However if you want to stay with the 75 cent outlets, then you use a pigtail. Join the 2 "black" wires to a third black pigtail wire that's about 6" long; join them with a wire nut or other splice. The pigtail goes to the 1 screw.

The trick with wire nuts is to tighten HARD, and do a "pull test" afterwards by holding the nut and pulling each wire firmly. If any pull out, that's bad technique; iterate until you get it right. That's not perfectionism. A splice that falls apart is a splice with poor contact that will arc and start a fire.

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  • Seriously, though, the extra buck or two for the "spec-grade" outlets just makes life so much easier!
    – FreeMan
    Dec 10, 2020 at 18:29
  • Is there an issue that the switch loop black & white are coming from different cables? I thought that was a serious no-no? Or am I misinterpreting what's going on with the black/white that are twisted together in the back of the box?
    – FreeMan
    Dec 10, 2020 at 18:32
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    Wouldn't 404.2(C)(5) exempt this switchloop from the grounded conductor requirement? Dec 10, 2020 at 18:35
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    @FreeMan The switch loop black & white are in one cable. That twist is the switch-loop hot (white) and the feed hot (black). My guess is that at the previous receptacle replacement, the wires were disconnected and those two wires twisted together so that when the new receptacle was put on, they would be put together (which is correct). Dec 10, 2020 at 19:19
  • Makes sense, @manassehkatz-Moving2Codidact, thanks.
    – FreeMan
    Dec 10, 2020 at 19:22
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Assuming that the bottom receptacle is switched:

  • Left cable is the feed from the breaker. (You can confirm this if you turn off the breaker, disconnect and cap (wire nut) all the wires and then turn the breaker back on and see which wire is hot.) Black is hot, white is neutral. Black goes to top, hot side. White goes to neutral (anywhere, since the tab is left in place).
  • Right cable is the switch loop. White is the hot feed to the switch, so it goes to the same place (in this old receptacle, another backstab that is also "top, hot"). Black is the switched hot feed from the switch, so it goes to the switched receptacle (bottom), hot.

For the new receptacles, use the screws rather than the backstabs. Normally brass-colored screws are hot (and switched hot), silver-colored screws are neutral.

  • Remove the tab on the hot side.
  • White from left cable goes to a neutral screw.
  • Black from left cable and white from right cable go together in a wire nut along with a short piece of black wire. The other end of that short piece of black wire goes to the top hot screw.
  • Black from right cable goes to bottom hot screw.

As noted by Harper, the right cable white (aka switch loop hot) should be marked with black tape to indicate it is a hot wire. Similarly, though not required, marking the right cable black (aka switch loop switched hot) red will make it clear to the next person what is going on.

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The white wire twisted to the black is carrying the hot to the switch. The black wire by itself is the switched power. It is a switch loop.

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    Thanks. Can you [add] something to this that wasn't already said yesterday to make this a more complete answer? Please take the tour and browse through the help center, especially the part on answering, to see how this place works and how it's different than a regular, run-of-the-mill discussion forum.
    – FreeMan
    Dec 11, 2020 at 14:28
  • Thanks Harper for the clear description and visual aid! I did upgrade to the screw & clamp outlet and it made the whole swap much easier. Everything seems to work fine at the moment. Thanks everyone else for their input - much appreciated to get advice from the experts!
    – Barrios
    Dec 11, 2020 at 17:12

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