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I wanted to replace this almond-colored outlet with a white one. Purely cosmetic. So far, huge mistake.

In any case, I took the outlet out, copied the way the old outlet was wired and … blew out my new $50 Wemo light switch.

Now I'm baffled. I checked the wires and can't make heads or tails of it. I'm handy, but no electrician.

I tested each wire with my multimeter—one lead on the wire, one on the ground—with the light switch on (pink) and off (blue). The results:

bafflng image

The old outlet was wired with:

  • two reds on the top as line
  • two whites on the top
  • black on the bottom as line
  • one white on the bottom
  • tab broken on line side, intact on neutral

I can't for the life of me see how this ever worked. Does this look right to anyone?

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    So one portion of the receptacle was always hot, the other portion was switched. You have ANOTHER switch that also controls it (wired as a three way). Does this make sense to you? Also, please confirm (for hot sake) that a single breaker turns off all hot, in all positions of the switch. Also, vacuum the box. I know a lot of people dont, but why leave that in there :)
    – noybman
    Commented Sep 14, 2017 at 3:08
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    Could you maybe write some actual voltages there? We need to know 122V vs 109V vs 74V vs 13V vs 0.74v. It really matters. One other thing, did the old receptacle have any tabs broken off? E.g. Between the screws? Before, was the outlet half-switched? Ae any other outlets also half-switched by the same switch (before)? Were any pins in wire nuts or were they all in backstabs or screws?
    – Harper - Reinstate Monica
    Commented Sep 14, 2017 at 4:32
  • @Harper, yes he had a broken off tab, and partly switched. He says that between title and in body. Thus my q on 3 way and breaker isolation
    – noybman
    Commented Sep 14, 2017 at 5:23
  • @noybman Yes to the single breaker. I will clean out the box 😃 I hate that every outlet I've replaced in this house has meant sweeping from all the junk that falls out.
    – nathanziarek
    Commented Sep 14, 2017 at 11:00
  • @noybman There's only the one switch for this room, but since nearly every switch in the house is three way, that wouldn't surprise me they wired it that way. The switch does have three wires coming to it, and they just bundled two of them on the top nut. I assumed that was in lieu of pigtailing.
    – nathanziarek
    Commented Sep 14, 2017 at 11:07

2 Answers 2

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This is a lot more straightforward than it looks.

  • All the blacks go together, and also to the hot side of one socket.
  • All the whites go together, and also to the neutral side of both sockets.
  • All the reds go together, and also to the hot side of one socket.

You need to break off the tab on the hot side of your new receptacle.

How do we know this? First, black is the first color people use for always-hot. And they're all nutted together with a pigtail. So that is almost certainly the genuine always-hot. Can't tell you where it's coming from.

Since you have a WeMo light switch, those are neutral, so the white wire on the switch loop must actually be neutral. Therefore the switched-hot is red. Since other receptacles are also switched, that also accounts for the other red wire. Now all the red wires are accounted for.

The supply must deliver neutral, and the switch and downstream outlet also need neutral. That accounts for all the white wires.

By the way, the neutral are hot because they have loads on them. Since you disconnected its neutral and it is still connected to "hot", the entire guts of the Wemo are now floating at 120V, including its neutral terminal and the wire attached to it. The same is true for something you have plugged into one of those receptacles in an always-hot socket. If you put an ammeter between these "hot" neutrals and the connected one, it would tell you what they draw.

The 3-way theory doesn't hold. Since black is always-hot, the other two would have to be messengers. The two messengers would have to go down another cable that is 3 wires, so that could only be the other /3. There would be a lot more wire-nuts in there, and there's be no way for switched hot power to make it to any other receptacle.

Wiring methods

The people who wired this were hacks. Using both backstabs and screws because you're too lazy to pigtail is appalling and illegal. It is possible to put 2 wires on/under the same screw, but you need to use products auch as Leviton's screw-and-clamp system, which are designed and listed for that. A commercial grade Leviton receptacle with that system is under $3. Never use screws and backstabs. Never use backstabs in any case.

If you don't want to use the Leviton or competitor system, just pigtail as you see the black was pigtailed. Get some wire nuts and short lengths of wire. You can buy 2 feet of 12/3 cable and cut it apart to get wires.

That may be #14 (not #12) wire, it probably was if they were using backstabs, most stabs won't take #12. 12 is a universal choice, but stiffer.

If I were you I would think about replacing every receptacle in the house. They probably backstabbed a lot of it, very common for builders in a hurry, also using the cheap 60 cent receptacles and switches. At least get rid of the stabs, they are bad news.

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    @nobyman explained.
    – Harper - Reinstate Monica
    Commented Sep 15, 2017 at 0:29
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    @noybman at first I had dismissed it as phantom voltage, but that didn't explain why the red wire didn't have any phantom voltage when off. I realized the disconnected wire was in series with a load.
    – Harper - Reinstate Monica
    Commented Sep 15, 2017 at 2:34
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    @Harper, your hypothesis is strong, in fact convincingly so I do not doubt it. But there is a remote chance as you noted, the work was hacked together maybe someone re-purposed a white, happens all the time, but I like your answer better.
    – noybman
    Commented Sep 15, 2017 at 2:56
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    Think of it like this:take a 9V battery, you hook it up with black and white wire. You run it through a 9v lamp bulb that has a socket on it, and "plug it in to an outlet. So you'd Have BLACK hot (9v+) going to an outlet, and white coming from the other side of the outlet back to the batter 9V-: Now, lift the white off the battery and measure from the white to the battery or a ground. You'll read near 9V the bulb wont light, but you'll think the white wire is positive 9V. Now picture that in this scenario, except you have 3 bulbs, 3 sockets, and you are reading the white wire be4 the battery
    – noybman
    Commented Sep 15, 2017 at 3:01
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    Don't I get a +1 for a model description easy to understand? @OP, to test this theory easily, just switch off everything on this circuit, and unplug too. Then with black wired as is in the picture, test again. You'll get different results. The whites should be 0. (provided there aren't and smart switches). The other possibility is under the same scenario, turn off the breaker, test a white you think is hot to the black with ohms, you should get readings in the megaohms or NR if the wires are NOT hot.
    – noybman
    Commented Sep 15, 2017 at 3:06
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You said the hot outlet had two reds on it. They were probalby just making a joint there and going to another box.

Do you have other receptacles in the room that are split-wired? If you were downstream feeding other receptacles from this one that are split-wired you wold need 3 wire cable.

So, black is hot, red is switched, white is neutral. One white wire is neutral from the panel, one goes to the switch and one goes on to other receptacles.

Black is always hot, one from the panel, one to the switch, and one on to other receptacles.

Red is switched hot, one back from the switch, and one on to the other receptacles.

Try that and see what happens. Use a standard single pole switch not the fancy $50 one. Just cap off the white in the switch box.

Good luck and stay safe!

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  • There are four receptacles in the room that are switched. I assume this is the first in the circuit due to its proximity to the switch, but I don't know that. I'm going to re-check the voltages tonight, but what I don't get is the "hot" white wire. That was reading 120-ish. Wouldn't wiring those together with the other whites (as it was wired) cause the breaker to pop? (As an aside, pretty sure the wife is nixing any more smart devices, so I can only lose equipment $2 at a time now!)
    – nathanziarek
    Commented Sep 14, 2017 at 18:47
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    Hmm, yeah I don't know how you can get 120 volts on the white wires at a receptacle with normal wiring. The only time a white wire is hot is to feed a switch under the old code. Now, the Code requires a neutral at many switch locations so you will see more 3 wire feeding the switch from the panel feed box. This is why I am guessing the reds are switched hots.
    – ArchonOSX
    Commented Sep 14, 2017 at 19:31

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