1

First, thanks for all the excellent advice on this site.

While wiring an auxiliary heat strip to the 125A sub panel in my basement, I noticed that the sub panel does not have a grounding wire from the main panel. The main panel is 25 feet away in the basement. I would like to add the ground wire. The neutral bar on the sub panel is not bonded; I will add the grounding bar. I am in North Carolina. Here are my questions:

  1. Can I run the grounding wire on it's own zip tied to the whip carrying the hot and neutral wires (I cannot pull any wires through the whip as it is pre-made)?
  2. I'm planning on using #6 wire. Is that sufficient for the 125A sub panel?
4

In turn:

  1. Yes, you can run the grounding wire on its own as per NEC 250.130(C) point 5. Also, since you are using a #6 wire, it can be run unprotected as per 250.120(C), although Bare Armored Ground cable may be a better bet to keep dimwits with wire cutters at bay. However, zip-tying the new grounding conductor to the existing feeder cable is a violation of 300.11(C). You're better off simply fishing the wire where it needs to go, or having it take its own route to the panel.

  2. Yes, 6 AWG copper wire is an adequate grounding conductor for a 125A subpanel -- in fact, 6 AWG copper is good all the way up to 200A. However, if you had aluminum or copper-clad wire instead, you'd need a 4AWG wire for the job.

  • I'm borrowing this spot for a question. I need a sanely priced panel that has bolt down breakers in all slots, and can support one of those gen interlocks like I rave about. Bonus points if it is rated for 36VDC, right now it'll be mains but DC someday. . . Small (12) due to space limits. Any brand suggestions? – Harper Jun 10 at 21:56
  • @Harper -- hit me up on chat sometime and we can talk about it :) – ThreePhaseEel Jun 10 at 22:53

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.