Is it okay to pigtail 12AWG and 14AWG on a 15AMP circuit?

Question

While working in my attic I lightly bumped a stud that had an outlet box as well as a switch that controls my attic light attached to it and when I did sparks shot out of the outlet and the circuit tripped.

When I looked at the breaker it says its a 15Amp circuit, so I shut it off and opened the outlet box that was sparking. Apparently that light bump was enough to knock a loose ground wire into one of the hot screws which caused the circuit to trip.

My problem is this, the outlet has 1 yellow Romex (12AWG) wrapped around the top screws (hot and neutral in their respective places) and 2 white Romex (14AWG) backstabbed into the outlet (also hot and neutral in their respective places). The problem is that all of the ground wires are simply twisted together and all 3 wires wrapped around the single ground screw.

So I figured I would try and do a proper job (or as much of one as I can) and connect everything to the screws using pigtails.

My questions are:

1. Should I pigtail all the hot wires to one hot screw, all the neutral wires to one neutral screw and all the grounds to the one ground screw?

2. Since I have a mix of 12AWG and 14AWG in this box (and my circuit is 15Amps) can I just use the wires from a strand of 14AWG Romex to make the pigtails?

3. Assuming the Yellow/12AWG wire is providing the power, would it be better to wire the yellow/12AWG wire to the top screws and then just pigtail the white romex together to the bottom screws? And all grounds pigtailed to the one ground?

Sorry, I'm not an electrician but have replaced a couple receptacles before. I was always told to never backstab and rather to use pigtails, to never wrap more than one wire around a screw and to always wrap in a clockwise direction.

Thanks for all the help in advance.

Answer 1

1. Yes.
2. Yes. It's no problem as long as you can get a good twist on the wires.
3. Pig tails can be 14 gauge since the branch circuit is protected by a 15A Breaker.

You'll end up with four wires in the wire nuts, 1 12AWG and 3 14AWG, so make sure you use the right size wire nut.

True, never more than one wire per screw. Lots of people don't like the back stabbing... Can you blame them? The name even sounds wrong. And wrapping clockwise generally improves the tightening operation if there is a slight twist in the wire but there is an argument that a pull on a clockwise hook puts a counter clockwise torque on the screw. I've heard arguments for both but I say either is fine if you tighten the screw to the right torque.

Answer 2

It sounds like ground was grossly mishandled.

First, a sidebar on metal boxes (you didn't say, but it sounds like a surface-mount box and metal is much classier there): All ground wires must go to the metal box FIRST. That's a Code requirement. They can be landed on individual ground screws, or pigtailed to the same ground screw - your call. Note that metal boxes do not require a ground "wire" to a switch - they pick up ground via the mounting screws. (To do that same trick, receptacles need a feature called "Self-grounding".*)

Even on a plastic box, the wire grounds should come together first, and should have pigtails to the devices. It is forbidden to have the grounding path for other wires dependent on a device being present - that's why devices only have 1 ground screw instead of 2.

Anyway to your questions... #1 is it really doesn't matter. On a plain receptacle with the tabs not broken, the 2 screws are simply connected to each other to provide a convenient splice method. Feel free to use it. If you have more than 2 wires to attach, you can also use the better "spec grade", $2.50 receptacles and switches, which usually have a "screw-and-clamp" feature that accommodates 2 wires per screw (4 on a receptacle, 2 on a switch).

I would avoid backstabs, because on this forum we constantly see "circuit went dead, breaker isn't tripped" problems, which almost always chase back to a backstab connection that failed, after a lengthy and frustrating bug-hunt.

Question #2, a 15A circuit requires wire 14 AWG or larger, so you're all set.

Question #3, your method of #12 to one screw, pigtails the others is fine.

The advice you were given is correct, but feel free to use all the screw-to-tighten connections available on regular receps (1 per screw) or spec-grade (2 per screw).

---

The only thing that ever came up to recommend jab-in backstabs, is the hard science showing that humans are absolutely awful at setting torques. They took a testing rig to electrician trade shows, and discovered master electricians couldn't set torques any more accurately than their spouses. Mistorqued screws are the source of many failures - in fact, if we knew then what we know now about that, aluminum wiring problems would have been seen differently. As a result, NEC 2017 was amended to require the use of torque screwdrivers on any device whose labeling or instructions specifies a torque. That means it's a codevio to not do it. Backstabs don't have torques.

---

---

---

* Receptacles need to carry ground current for any device plugged into them, so 'self-grounding' on a receptacle means they have some extra bits to assure screw contact is good enough for the job.