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I want to supply power to a walk-in closet that I just framed. Well, I split a large room into two sections (the closet is smaller) and want to use the current circuit to supply outlets on the new wall and an overhead LED light.

Will I violate code if I split the circuit in a standard size outlet box and feed the other wall receptacles and the light (switched) as well? That would mean one wire in and two out obviously.

Is this acceptable? Should I wire nut everything together with a pigtail feeding that outlet? presumably I could use a combination of the screws and holes in the back of the outlet but that seems like a real hack.

Thanks.

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  • How many outlets and lights are currently on the circuit? You're putting the new outlets facing the room right? Are there any outlets that are now in the closet that could be removed (closets typically don't have outlets)? – JPhi1618 Oct 16 '15 at 19:05
  • Well, never mind. It looks like "number of outlets on a breaker" is not specified by the NEC, but the "rule of thumb" seems to be 10-12. I do know that the size of the electrical box you use depends on how many wires it holds, so that is one thing to check on. – JPhi1618 Oct 16 '15 at 19:35
  • I believe there are currently 4 outlets and one overhead light with a pull-switch (this is in a basement). I will be adding 3 outlets, 2 facing the large room and one facing the walk in closet (for convenience of vacuuming the floor etc) and one new overhead light. I will wire the light to a switch but for the purpose of the question it's irrelevant as it will be at the end of the run. – HelluvaEngineer Oct 16 '15 at 19:37
  • Oh, and for the boxes in question they are the standard 1 gang receptacle ones but I got the deep ones, approx 3.5 inches deep. – HelluvaEngineer Oct 16 '15 at 19:40
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So, the National Electric Code doesn't say anything about the number of outlets on a breaker, but it does specify the number of wires allowed in a junction box, which seems to be your main question.

Box size

Since you have no drywall, we can assume that you are using "New work" boxes, but you should check their labeled size (in cubic inches - ci) to be sure of what you're working with. A typical "deep", new-work box is 22ci. If you are using 12/2 Romex and putting an outlet in the box, the required size is:

  • 6 conductors coming into the box: 6 * 2.25 = 13.5ci
  • Your outlet counts as 2 conductors: 2 * 2.25 = 4.5ci
  • The ground wires count as one: 1 * 2.25 = 2.25ci
  • Required size: 20.25ci

So, you should be fine. If you're using 14/2 (probably - I went with the worst case for the example), the multiplier is 2ci rather than 2.25ci.

Wiring it together

If you have one pair coming in a box and one going out, using the screws of the outlet isn't a hack, and they even sell nice "backwire" outlets that are made for that. In the box where you are "splitting off" and you have three pairs, a pigtail to the outlet is probably better than filling all the holes in a backwire outlet. (Note, the pigtails don't count for the cubic inch calculations)

Also, in your "junction box" all the wires need to be folded nicely and pushed to the back before installing the outlet. The outlet shouldn't be used to force the wires into the box - you should be able to push the outlet all the way in with no resistance from the bundle in the back.

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    Keep in mind that the size wire you use, will dictate the breaker size. If you use 14 AWG wire, you'll use a 15 ampere breaker. If you use 12 AWG, you can go up to a 20 ampere breaker. – Tester101 Oct 16 '15 at 20:31
  • Thank you for that comprehensive response! That completely answers my questions. It is a 15 amp circuit, btw. – HelluvaEngineer Oct 19 '15 at 17:32

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