I'm adding a doorway under a stairwell and ran into wiring running through the wall. My question is specific to the wiring. I'm planning to add a junction box on each side, splice, and then extend the circuit up over the door frame. Maybe add one outlet.

The orange cable goes to the washer/dryer, and the white runs into the house for outlets in the laundry room while the yellow runs to the main room in the house.

My questions are around splicing and where I might add the single outlet. I need to splice all three and remove the 2x4 in the middle. Can I just use push in connectors on the orange, yellow and white cable to add a few feet? Can I also add an outlet to the yellow or white cable the same way (which I assume are both 120v)?

wiring within wall

  • Few small things - you know the junction box has to be accessible right? You can't close it up in the wall. Also, that orange cable is probably 10 gauge wire, so I don't think you will find push connectors for that. I'm not sure if 3 different circuits can all share the same junction box.
    – JPhi1618
    Jan 16, 2020 at 17:24
  • Interesting. So I may, potentially, need 6 junction boxes (3 for each side)? The boxes will be accessible. They'll be inside the new (unfinished) room. I suppose 6 boxes isn't that big an issue, but how do I splice the orange? I picked up the orange push in connectors thinking they were meant to color match. Jan 16, 2020 at 17:29
  • 1
    The colors don't really work that way unfortunately. You will most likely need wire nuts (the ones that size are commonly red, but you really have to read the package). The white cable is probably 14ga and the yellow is probably 12ga, but the should all be labeled. Wait for an answer on the multiple boxes - I'm not sure about that, but we have some good electrical users here.
    – JPhi1618
    Jan 16, 2020 at 17:32
  • 1
    @JPhi1618 Write this up as an answer.
    – JACK
    Jan 16, 2020 at 17:41
  • 1
    @JPhi1618 I think isherwood is referring to making outlets with the #10.
    – JACK
    Jan 16, 2020 at 17:51

1 Answer 1


A large enough junction box

First, you are going to need a very large junction box to do all this splicing. Let's count conductors.

  • Two /2 cables and one /3 cable = 7 conductors to splice.
  • Plus the 7 conductors they'll meet in this box.
  • Plus 1 conductor count to cover all ground wires
  • Plus 1 conductor count to cover all cable clamps
  • Plus 2 conductor count to cover the receptacles

I count 18 total. Let's assume 12 AWG wire, so 2.25 cubic inches per conductor, that's 40.5 cubic inches.

A 4-11/16" steel deep junction box will suffice. (steel makes it immune from nails coming from the other side. This is a deep box.)

Improving aesthetics

Now, to make this thing aesthetic (nobody wants a giant blank plate there), I recommend topping off with a 1-gang "mud ring". That way it will appear to be a normal receptacle.

You're on the right track with "put a receptacle there rather than have a blank plate". However, I'd do a couple things different: First, I'd reroute the cables to a more desirable/expected place for a receptacle, rather than having a receptacle in an odd place for no reason. Second, I'd do it on both sides. Mind you, it wouldn't hurt to make it a little odd; someday these circuits may need maintenance, and you want to hint to the maintainer where these splices might be.

Watch which circuits.

A circuit is "grandfathered" when it only has to comply with the Code written when it was installed, and doesn't have to be updated with each new Code revision. However, there's a fundamental rule: When you're grandfathered, you can't make things worse.

Read the current Code on laundry room outlets. I believe it says the circuit must be dedicated and you can't add outlets to it. That's because when you have separates, the washer is powered off that and the dryer is powered by the 120/240V split-phase. (they make "physically separates" where the washer plugs into the dryer, but they use some sort of internal design features to avoid overloading, since a 120/240V circuit normally doesn't have the capacity to feed both).

If someone hack-a-dacked your dryer outlet to include a 120V outlet, that should be remedied ASAP because it's a code violation. Also the washer outlet is supposed to be 12 AWG/20A (yellow or larger). Also make sure the dryer outlet and cord is NEMA 14 (4-pin); it's obviously a modern installation, but sometimes people fit the obsolete, dangerous and illegal NEMA 10 3-prong dryer outlets on newer houses to match dryers from older homes (you're supposed to change the cord, but builders don't feel that's their bailiwick).

If the other circuit goes to a bedroom, then that is the one to tap for receptacles.

Grounds can go together. Neutrals must obsessively separate

It's OK to clump all the grounds together,(don't forget ground to the junction box if it's metal), but not required.

Separating neutrals is absolutely required. Don't bundle all the neutrals onto one big wire nut!

Actually, (this is a bit OCD) but I might actually use different color wire nuts for the different circuits - red for the #10, yellow for the #12, and orange for the #14 (if it fits). It's sheer coincidence the colors are that way.

Give yourself LOTS of wire length inside the box - a full 12" (including in this case, an inch or two of sheath sticking out beyond the clamp, for cable identification purposes). The 12" will seem ungainly to work with; but it'll go easier if you splice the grounds and push and tamp them into the back of the box first, then (after testing) push back the dryer conductors, then the laundry room (since you won't be tapping it), and finally the other circuit so it's on top.

The mandatory wire length is about 7" - six inches beyond the cable clamp/sheath AND 3" beyond the finished surface of the wall. However you'll hate working on it if you do that, and it'll be a code vio to cut it at all, which is leaving yourself no freedom.

Connector types

I would not use push-in connectors unless you enjoy really nasty, difficult troubleshooting problems involving guessing where mystery splices are (remember, we are creating two mystery splices here). Push-in connectors, like their "backstab on receptacle" brethren, involve a single, tiny point of contact for all the current to flow through. The manufacturers have gone in backflips to assure this fails safe, i.e. with a burnout/open instead of a flaming arc fault, but the fact it does fail. The other problem with stab connections is they say they're multi-gauge, but who's kidding who? The receptacles said the same thing and that turned out to be a lie, and UL delisted a bunch of 12/14 backstab receps.

Wago style "lever" connectors are certainly a better choice than push/stabs. I'm competent at wire nuts, so I recommend those. The trick with wire nuts is tighten them HARD, and do a vigorous "pull test" holding the nut and yanking each wire. If any wire pulls out, that's an electrically bad connection that will fail, and requires you improve your technique.

enter image description here enter image description here src:diy.se

Code doesn't care about rubbish splices that fail safe, because the National Electrical Code is written by the National Fire Prevention Association and devices approved by (insurance) Underwriter's Laboratories... not the National Make Your Electrical Work Association and Reliability Laboratories.

  • I haven't heard of that last organization. Got a link?
    – isherwood
    Jan 16, 2020 at 18:07
  • 1
    @isherwood Sure. youtube.com/user/bigclivedotcom/videos Jan 16, 2020 at 18:09
  • @Harper can you elaborate on the following. "The mandatory wire length is about 7" - six inches beyond the cable clamp/sheath AND 3" beyond the finished surface of the wall. However you'll hate working on it if you do that, and it'll be a code vio to cut it at all, which is leaving yourself no freedom." Are you talking about the wire inside the box, if I go with 12" I'm good right? That makes me think of another question. Since I'm adding wire (up and around the door frame), do I need 12" inside the box from each wire (in and out)? Jan 16, 2020 at 18:11
  • @DirtDiver31 Yes, my reco is 12" - somewhat less is leeeegal but it'll suck. Yes, 12" on each cable coming into the box. Jan 16, 2020 at 18:13
  • 1
    A Carlon box would work if you have the cubic inches and have a metal nail-guard plate on the back side. I prefer steel boxes since they are their own nail plate, but go to a real electrical supply and get a 4-11/16" box with nailing wings. (they are cheaper at the electrical supply anyway, I pay $3-ish for wingless ones). But I wouldn't put it right next to the door - you would't want contention between the outlet cover and door trim. Near the door is also odd for an outlet (but fine for a light switch; that'd work great!) Jan 16, 2020 at 18:44

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.