I had some spare 10/3 NM cable from which I repurposed the black, white, and bare wires and ran through conduit. There's a circuit junction nearby that doesn't have a ground and isn't spliced inside a j-box. The line side is just a hot and a neutral. The load side goes to a light outside and is 14/2 NM cable. The spare red wire from the 10/3 NM, can I use that to ground the 14/2 NM and just identify it as a ground with green electrical tape every few feet?

The portions of the NEC I've read pertain to identifying the neutral but I can't find something that references the coloring of an earth/grounding wire.

  • 2
    When you say you "repurposed" the black/white/ground from your 10/3, does that mean you pulled the individual wires out of the cable sheath? If so, as I understand it, that's a code violation. It's not that the wires are suddenly different, but that they're not labeled for individual use, so an inspector (or future electrician) doesn't know what kind of wire they are. You can use them as pig-tails in a box, but not for running through conduit. – FreeMan Nov 23 '20 at 1:49
  • @FreeMan, yes I pulled them from the sheath and I've looked at the individual wires. They aren't labeled. It's a short run, so I'll buy suitable wire to re-run through the conduit. Thanks for pointing that out. The crux of my question, however, is can I use that red wire as a grounding wire on another circuit without stripping off all the red insulation and just use green electrical tape to identify it as earth ground? – user208145 Nov 23 '20 at 1:56
  • 1
    Fairly sure that bare, green, green with yellow stripe are called out as the only acceptable colors for grounding/equipment ground conductor and as unacceptable for any other use somewhere in NEC. Beware getting confused by the grounded conductor, better known as neutral. – Ecnerwal Nov 23 '20 at 2:05
  • 2
    250.119 appears to the be the section of NEC to see the color details. – Ecnerwal Nov 23 '20 at 2:16

Keep in mind that you can't use wires pulled out of cable because the insulation is not marked. You also have to have all splices inside a junction box.

But to answer the question, you can't use a red wire for ground, but you can strip all the insulation off the conductor because a bare wire for ground is OK. It might take a few minutes depending on the length and the tools at hand.

  • Yup, hit all the key points. – Harper - Reinstate Monica Nov 23 '20 at 4:31
  • Could the wire be marked with green tape? – Matthew Nov 23 '20 at 4:32
  • I'm pretty sure you can't recolor individual wires with tape unless the are bigger than 6 ga or so. There is some exceptions for remarking conductors in sheathed cable but I don't think that applies to ground. – bigchief Nov 23 '20 at 6:45
  • Make sure that if you're stripping the red insulation off that wire that you don't nick the copper itself. I believe that, too, is a code violation. – FreeMan Nov 23 '20 at 17:59

Bigchief covered the subject pretty well. To add a few points:

  • The junction that is not inside a J-box is going to need to be re-done so the splice is inside a J-box and legally done (cable clamp on the sheath, 6" of wire length inside the box).

  • You are trying to retrofit ground. In 2014, Code changed to give you a great deal of freedom to do that. Search this site for more. Don't re-task red; simply tap the ground wire already in the /3. Do this in a Code legal way.

  • Thanks. Inside my basement there's an open air splice from a 14/2 NM that goes outside; upstream from the splice is a hot and neutral. This was my original question but the answers fortunately got off on a tangent about my using 10/2 conductors stripped from the NM sheath. I'm re-pulling that now. I've stripped the red 10ga wire so it's down to bare Cu. Can I connect a proper ground from the circuit I'm working on to the unused ground from the 14/2 NM? The ground for that is cut flush at the sheath. All of this I plan on doing inside a metal enclosure. – user208145 Nov 24 '20 at 1:16
  • If you are retrofitting ground to a circuit that has no ground and was legal when installed, I believe you can connect just a ground to any circuit nearby. However, This looks like it might have been wrong when it was installed and might need to be replaced in order to meet code. – bigchief Nov 24 '20 at 2:25

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

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