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I am installing a subpanel in my garage and feeding it from the main box with 6/3 romex. I ran the cable across the basement ceiling, through the wall into my garage. I was able to run it up through the wall that separates my house from my garage, into the garage attic, over to the other side of the garage and down the wall to the subpanel.

Inside the wall I used several staples to make sure the cable stayed away from the drywall. However, now that I have the cable in place, I'm uncomfortable with the unprotected 60 amp feed running through a wall that someone could drive a nail through. I understand I can't run it through conduit, so what is the best way to protect the cable (hence, PEOPLE) from damage?

  • Why can't you run it through conduit? – Tester101 May 29 '17 at 22:47
  • My understanding is that running romex through conduit for more than 24" (?) is a no-no. – Darvis Lombardo May 29 '17 at 23:18
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    No it's absolutely fine to use conduit as a convenient material for a protective shield. In this case you are not using it as a wiring method, so the rules are relaxed. – Harper May 30 '17 at 1:08
  • If you use a conduit, make sure it's a metallic conduit with the conduit electrically bonded to the grounding system. This way, if a fastener does puncture the conduit and strike a hot conductor, the fastener will immediately cause a short to ground and trip the feed breaker. With a nonmetallic conduit like PVC, the fastener could be energized and a potential electrocution hazard. – cathode May 30 '17 at 17:44
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The same puncture issue exists with any in-wall wire. Check local codes, but most require wires to be run along the middle of studs which, for 2x4 studs. is 1 3/4 in from the wall board. If your feed is 120V, the shock danger is about the same regardless of gauge. Without being able to get inside the wall, there's not much that can be done.

Alternatively, you could use shielded flexible conduit or rigid conduit. The first is expensive in your gauge, the second requires wire length access above or below the wall or can be mounted on the wall. Doesn't look too hot that way.

I started using flex conduit for blind runs long ago because it can be pushed to fish, is easier to fish and location inside the wall doesn't matter much. Entrance and exit holes have to be centered but it doesn't have to be attached inside.

  • I should not have said "fish it up through the wall" as that was not accurate. I have the drywall off on the garage side, so I was able to run it up the stud, keeping the cable as close to the middle as possible and stapling along the way. If it were just a 120V run I wouldn't worry about it, but it's a subpanel feed so there's potential for a 240V zap on a 60amp circuit. That's what concerns me. – Darvis Lombardo May 29 '17 at 23:17
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    In fact, the potential (in the USA/Canada distribution system) is still just 120 volts - each hot is only 120V to ground. 240V only exists between the hots, and you'd be hard pressed to invent a way to get that by poking a hole in the cable, other than shorting the cable out and causing the breaker that protects the cable to trip. – Ecnerwal Jul 8 '17 at 20:11

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