0

I am replacing the circuit to our stove and am doing the rough in currently. We may one day want a stove requiring more amperage than our current 40 amps and so I am replacing with 6-3 w/ground. I have the wire stripped back and pulled into the metal receptacle box and am trying to find a code compliant way to connect the bare ground from the cable to both the outlet and the metal box. I have seen and read about numerous different ways to do this but don't know what is code compliant.

I have looked into purchasing a grounding pigtail and read that any grounding wire I purchase to help connect the metal box to the wiring and outlet needs to be 10 awg as this gauge is good as a grounding wire up to 60 amps. Because the 6-3 is good for 55 amps the 10 ash as a grounding wire is what I need. If I am wrong about this please let me know.

If I can go with a pigtail then...

  1. where do I find a 10awg pigtail? I can only seem to find 12 awg pigtails.

  2. If i can't find a 10 awg pigtail then is green insulated thhn wire in proper gauge acceptable?

  3. how do I connect it all? Can both the pigtail and the bare ground from the wire be placed into the receptacle and screwed down or is there a different way I need to connect them?

Thank you for your input and if I left out any needed info please let me know. Ben

Improve this question
3
  • You use whatever scraps (of appropriate length) of wire you have left over for making pigtails. You should have a hunk of that 6/3's grounding wire laying around still from when you cut it to length, use that for your pig-tail.
    – FreeMan
    Commented Apr 15, 2021 at 18:18
  • I pull the ground from the cable tight around 180° around the ground screw first, then continue that wire to the device. external-content.duckduckgo.com/iu/… .(except they wrapped the wrong way.) It may not work withh your specific box.
    – NoSparksPlease
    Commented Apr 15, 2021 at 19:07
  • @NoSparksPlease oh that's even better. But it may not be necessary in a metal box.
    – Harper - Reinstate Monica
    Commented Apr 15, 2021 at 19:27

2 Answers 2

Reset to default
3

You MUST attach the ground to the metal box FIRST. You can pigtail, but what you can't do is take ground to the receptacle only.

The receptacle will automagically pick up ground off the metal box in certain circumstances.

  • the box screw ear, and receptacle, have hard flush clean metal contact, with the screws bottomed out (not floating on drywall ears; no little plastic squares on the screws). Or
  • the receptacle is labeled "self-grounding" meaning it has a feature to assure good contact with the mounting screw.

If neither one happens, use a pigtail.

Pigtails wires are not special wires. They are just plain old wire.

You're getting hung up on the idea that a pigtail is a special/magic product that comes in shrinkwrap with a UPC code. While it is true, that they do sell pre-assembled ground screws + pigtail wires, that is only a matter of convenience for people with more money than time. Normal people make their own pigtails out of common wire.

The ground screw in the back of the metal box is tapped #10-32 and any short 10-32 machine screw will suffice. They sell little green "ground screws" if you're fancy.

So go down to the "wire sold by the foot" section and buy yourself 1' of green or bare #10 solid THHN wire.

That's it.

If your store doesn't sell wire by the foot, then never shop there again - supposed cost savings are probably marketing lies. Obviously you won't "save big money" buying a 50' roll of #10 green wire when you only need 8 inches.

Improve this answer
5
  • Yesterday I bought 12" of #10 green for 51 cents an Home Depot.... I have damn near every color and size.... except that... lol
    – JACK
    Commented Apr 15, 2021 at 19:43
  • Thank you for your input guys, much appreciated. I understand the pigtail wire is nothing special and am just making sure there isn't a NEC code requiring some specific way to wire it. It sounds like a piece of thhn or a piece of the ground wire from the 6-3 will be fine and code compliant.
    – Ben
    Commented Apr 15, 2021 at 20:26
  • I like the simplicity of first looping the wire around the ground screw on the box and then to the outlet. I thought perhaps getting a ground lug to screw onto the grounding point on the box and then run the 6-3 ground to the lug and a strip of 6-3 ground or thhn from the lug to the outlet would be a good idea to really secure it but am not sure if this is a code violation. Alternatively I have heard others say just to add a length from the grounding screw, a length from the outlet and twist them along with the 6-3 ground and then wire nut it.
    – Ben
    Commented Apr 15, 2021 at 21:11
  • @Ben "add a length from the grounding screw, a length from the outlet and twist them along with the 6-3 ground and then wire nut it." This will work but now you have three #10's and a wire nut to shove back into the box along with 2 hots and a neutral. Add to that, the large outlet. I try to minimize wire and wire nuts.
    – JACK
    Commented Apr 15, 2021 at 21:54
  • Again, if one of the "self-grounding" options works for you, you don't need any ground wire at all, other than the 1 from the cable. 1 ground wire is better than 2 or 3.
    – Harper - Reinstate Monica
    Commented Apr 16, 2021 at 3:58
2

Take the #10 AWG ground from your cable and loop it to your metal box with a 10/32 grounding screw. There should be a threaded hole for this in the box. Extend the ground outward an attach it to your outlet.

Improve this answer

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.