Use of pigtails for wiring outlets

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En2020

Main Question or Discussion Point

I read in an old thread that backstabbing an outlet is now discouraged, and that one should use pigtails. I also read that putting more than one wire under a screw is also dangerous/risky and therefore not advised. I have a few questions and hope everyone will indulge me.

In wiring an outlet, and assuming there a line in and at least 2 lines out:
1. Can/Should you use pigtails for all three lines (hot, neutral, and ground)?
2. If I see both 12 and 14 gauge wires for an outlet, what size wire should I use for the pigtail? Specifically, Line in is 12, Line out is 12 and 14.
3. How many wires, in practice, should be a max for an outlet (including line in and all the outs and the pigtail)

Thank you
 

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  • #2
Averagesupernova
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Backstabbing has nothing to do with pigtailing. Backstabbing is what is referred to when shoving the wires into the quick connect terminals in an outlet. You can pigtail and still use the backstab terminals. Often times in a single gang box more than two cables coming into the box will exceed the allowed wires. Let me guess. You are adding an outlet someplace and taking power from an existing.
 
  • #3
.Scott
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I read in an old thread that backstabbing an outlet is now discouraged, and that one should use pigtails. I also read that putting more than one wire under a screw is also dangerous/risky and therefore not advised. I have a few questions and hope everyone will indulge me.

In wiring an outlet, and assuming there a line in and at least 2 lines out:
1. Can/Should you use pigtails for all three lines (hot, neutral, and ground)?
2. If I see both 12 and 14 gauge wires for an outlet, what size wire should I use for the pigtail? Specifically, Line in is 12, Line out is 12 and 14.
3. How many wires, in practice, should be a max for an outlet (including line in and all the outs and the pigtail)

Thank you
I Live in New Hampshire, the "Live Free or Die" state.
Where are you and what kind of building are you working on? The answers to those questions will indicate what kind of electrical codes you will need to follow.

Here are my rules:
1. Probably. What is important is what not to do. Don't attach more than one wire to a single screw. Also, I always use a metal box and tie the ground to the box. Most electric outlets have at least two connectors for live and neutral - so you will only need to pigtail one of them. Same for ground, but there may be more than two ground terminals of the outlet and the box may require a line.
2) Go for the best connection under that screw cap. Generally, the pigtail should be the larger of the two (12). The key is a good connection.
3) The problem gets to be how many will fit. It not so much a max for the outlet as it is a max for the box. Normally, three is the most that you need - and if the box is small, you can already be in trouble. If you really do need four, you could go with a larger outlet box, but I would be thinking of using a separate box at that point.
 
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En2020
Awesome! Thank you for the responses.
 
  • #5
Averagesupernova
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In some places it is mandatory to use pigtails. This translates into only 3 wires connected to the outlet. Hot, neutral, and ground. The reason is to allow the homeowner to easily replace the outlet. Too many wires for John Q. Homeowner to deal with otherwise.
-
This link will tell you about box fill. http://www.ecmweb.com/code-basics/box-fill-calculations
I am betting you will be over the limit.
 
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En2020
Averagesupernova, thanks for sharing that useful resource.
 
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jim hardy
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Averagesupernova, thanks for sharing that useful resource.
I second that !
from that great link -
How to get same effect as two wires under one screw
upload_2017-9-21_16-33-39.png

strip insulation and bend the wire around the screw.

just gotta think before you cut.
 
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To be thorough, one might refer to the UL White Book which covers receptacle terminals under section RTRT, Receptacles For Plugs And Attachment Plugs. Of course one should be knowledgeable enough to do their own homework on whatever product they may choose for a specific job, should they contemplate any sort of task like this. Not all duplex (or single, twistlock, ect.) receptacles (snap switches, contactors, ect.) are created equal.

Probably not an issue in many circumstances, but one also needs to be aware of the current standards that may apply to their installation; for example there is a good chance that the above "EC&M/Mike Holt" link may be out of date (2008) with currently adopted codes in any given locality (there have been a *few* subsequent changes, NEC runs on a three year cycle).

I hear the style in Jim's referenced picture has always been vogue in Chicago, where even stick-built residences are wired in conduit and individual conductors rather than cable. You have to have spent some time with a bender in your hand to really appreciate what that implies.

EDIT: Re-reading the OP, I see there was also a question of wire size. Put simply, wire size is largely dependant on the branch circuit rating. There can be other factors, for example ambient temperature, however it's usally at worst an err on the side of caution to go with the large end, maybe larger, of conductor sizes present on a particular circuit when attempting any addition or modification. Provided it still complies with all applicable codes and standards, of course!
 
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  • #9
Averagesupernova
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There are certain things that likely won't change. I don't expect box fill to change. Grounding methods seems to be constantly evolving. Some locals are likely still on 2008 code.
 
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There are certain things that likely won't change. I don't expect box fill to change. Grounding methods seems to be constantly evolving. Some locals are likely still on 2008 code.
One thing which came in with 2011 were some changes on device box depth allowances, which were already heavily modified in '08; NFPA70-2011 Art. 314.24 (A)(1) and (A)(2) adds the words "devices or" to establish that the code applied to any equipment mounted in an outlet box regardless of whether the intent of said equipment was primarily to "utilize" electricity or not. This closes a loophole where devices just short of the previous 48mm (1 7/8 in) rule might still wind up legitimately packed into an impractically sized j-box. It's sufficed to say that there is an awful lot to consider when you're doing the day to day task of stuffing wires into a box. This thread doesn't nearly cover it.

You are right about many localities not being "with the times" on code. Our current is now two cycles behind...for the moment. Never forget that litigation and politics (read:money) drive the industry. I suppose all industries?

I'm not sure how much is really changing with grounding save for revisions to improve the simplicity of code applications and general organization. People have been grounding stuff poorly as well as in overkill for as long as I can remember. I don't think the right way in the eyes of the code has actually changed that much since the elimination of premesis side neutral equipment grounds.
 
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jim hardy
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I'm not sure how much is really changing with grounding save for revisions to improve the simplicity of code applications and general organization.
They're trying to become more consistent in use of words 'grounding' 'bonding' , and clarify distinction between earth ground and neutral.
 

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