In order to finish wiring up my range and cook top (Splicing 6/3 wire to multiple 8/3 wires (or even other 6/3 wires) inside a junction box), I will be pulling 10/3 and 8/3 NM wire, respectively, from a junction box affixed to a basement joist, along the top basement joists, through the basement ceiling (kitchen subfloor), to two separate junction boxes mounted inside of my kitchen cabinets.

The range and cook top both have aluminum flexible conduit shielded wire coming out of them, going to the under-counter junction boxes.

Question - Does the NM wire I'm pulling up from the basement to those j-boxes require to be protected from damage (NEC 300.4 or others code sections) by similar or other type of shielding -

a) along the joist/through the subfloor plywood hole (I don't believe so, just confirming),


b) in the short space inside the kitchen cabinets before they enter the j-boxes (both cabinets have doors)?

Any applicable 2017/2020 code sections would be much appreciated with the commentary.

  • aluminum flexible conduit shielded wire That sounds interesting. Is it aluminum wire? Because if so, that raises aluminum-copper connection issues as standard 10/ and 8/ cables have copper wires. Or is aluminum conduit? Because that doesn't sound terribly strong - I think most of the time the conduit is steel. Commented Jun 9, 2021 at 16:31
  • 3
    MC-Lite cable or equivalent flexible-conduit, almost certainly aluminum armor with copper conductors. Not uncommon at all.
    – Ecnerwal
    Commented Jun 9, 2021 at 18:32
  • Ecnerwal, that is correct, it's copper wire (multistrand) inside the aluminum flexible conduit. Hoping someone can chime in on whether the NM wire leading up to the junction box needs protection inside the cabinets or, if not, can be put inside similar shielding to make me feel better that a pot or other hard object won't somehow puncture the NM sheath. Alternatively, I can always box it off with plywood, but i'd prefer not to.
    – sil80
    Commented Jun 9, 2021 at 20:04
  • @Ecnerwal Thank you. I'm just an amateur, and that makes perfect sense. Main thing was to make sure this wasn't aluminum wire. Commented Jun 9, 2021 at 21:45

1 Answer 1


If the nm is exposed in the back of the cabinet yes the NM would have to be covered where exposed. I will use a water heater because it’s easier visualize.

Where the cable comes out of the wall I slide a piece of flex over it long enough to connect to the heater J box, I do use anti short bushings but the outer sheath of the NM is sufficient for most inspectors (use the bushing just extra protection).

The nm is stapled in the wall on the stud and the box end in the water heater box if not a tight fit where the conduit exits the Sheetrock I silicone it in place.

If exposed inside the cabinet you do the same from the wood hole to the J box the armor meets code for protection inside the cabinet where nm would fail inspection if the inspector saw it.

  • Much appreciated, Ed!
    – sil80
    Commented Jun 10, 2021 at 2:31

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