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While doing some work inside my basement ceiling I discovered a small tear in the outer insulation on a Romex cable, and similarly a cracked open BX cable (outer armor slightly unwound for one turn).

I'm the homeowner, and both of these are existing circuits. In each case (Romex and BX) what is the best thing to do? What is the easiest thing to do that would be acceptable even if not best?

There is no damage to the inner wire insulation, paper, nylon strands, or other components of these cables. Only the outer jacket.

I could

  • leave them alone
  • tape the romex or use a patch kit, and add staples on both sides of the patch
  • run them through junction boxes without cutting them, just put the damaged bit inside a box as is. I'd have to modify the box to get the wire inside with strain relief and without cutting it
  • cut them and add junction boxes. I'd have to cut them twice and add two boxes with. splice between and all this would be buried in the ceiling
  • rip it all out and run it again. I could do this for one of them because it runs entirely in the basement ceiling. This would be a full-day job. The other one runs into a wall upstairs so it's not even an option.
  • I saw on another post there is an $8 Tyco splice kit for Romex (but not for BX). Given the damage is limited to the outer plastic jacket, is that really any better than wrapping it (the Romex) and stapling it?
  • any other solutions?
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  • I believe option 3 is right out. Once you've modified a JB to get it around an uncut cable, it no longer meets its UL listing standard and is, therefore illegal to install. Also, it must be installed according to the directions with it, and I doubt you'll find a JB that has instructions on how to cut it up to wrap around an existing cable.
    – FreeMan
    Jan 29, 2021 at 14:59
  • The junction box(es) would have to remain accessible forever. @Freeman I think OP means to detach the wires from their destinations and then thread them through e.g. a metal box with KOs, preceded and followed by cable clamps as needed. Be tricky; you'd have to ground the box and BX is not a valid grounding path (for reasons which should be obvious lol).
    – Harper - Reinstate Monica
    Jan 29, 2021 at 19:41
  • @Harper-ReinstateMonica hello. My accepted answer is what I was hoping to find. Maker claims it ok for MC. It has no grounding screw, its purpose is to enclose things without disturbing them. Surely better than leaving them. Much of my home uses BX armor for ground. Adding one more box, while perhaps not strictly subject to grandfathering, must be better than leaving damaged cable exposed no? With NM it's not grounded. Accessibility in my case is good, an open basement ceiling. But were it not, if just as inaccessible as the damage isn't this a step in the right direction?
    – jay613
    Jan 29, 2021 at 21:11
  • I would tend to agree with "better". Our bias here is to say what's Code, because a code-violating solution is understandably a downvote magnet. Even so, you could lick the grounding problem by bringing a bare ground to the box from any grounded location. Erm, that may not be quite legal either but it's in the spirit of the 2014 ground retrofit rules.
    – Harper - Reinstate Monica
    Jan 30, 2021 at 1:54

2 Answers 2

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As others have pointed out, you aren't allowed to modify a box as you propose in option 3, but there are open splice boxes for this purpose. These are designed for enclosing illegal bare splices and made with slots instead of holes, so you could slide the damaged NM cable in without cutting it. Here's an example of one: https://www.garvinindustries.com/54171-opr

enter image description here

I'm unaware of a version for BX.

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    Thanks. The manufacturer states it can be used for MC cable too. I think the "easiest cheapest" version of my answer would be this for the MC cable, and rubber splicing tape for the NM. But this box only costs $8 and I only have two repairs, so I suspect the best overall approach will be two of these. Note your photo doesn't show it but there is strain relief inside, and this box can be used in my situation (damage to outer jacket) and also to enclose open splices without disturbing them. I'm happy to say I don't have any of those, but this is nice.
    – jay613
    Jan 29, 2021 at 16:36
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With the Romex, I'd get some rubber splicing tape from your electrical supply store, maybe from your home store, and wrap a layer of it starting at two inches before the tear and ending two inches after the tear. Then add a layer of vinyl electrical tape over that. This is after you've made sure no damage has been done to the wire insulation. If you're in doubt, just use the double junction box (dog bone).

With the BX, your solution with the two metal junction boxes would be the best solution. Keep in mind that the junction boxes have to remain accessible so they can't be totally buried in the ceiling with no access.

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