Running wire across basement to electrical panel. Drilling and running perpendicular to joists, need to do a right angle turn and run parallel. Does the wire have to go through a joist before the turn, or can it go to the next joist, turn, and be stapled to the face?

  • 5
    Other than grounding system wires, all wires must run in conduit. Only cables can run through joists without additional conduit protection. You probably mean cables, but it's an important distinction, so use the right terms.
    – Ecnerwal
    Apr 23 at 23:58
  • 2
    What country is your building in ?
    – Criggie
    Apr 24 at 9:18
  • US. Thanks for responding. Found the info I needed.
    – DIYer
    Apr 25 at 3:50

1 Answer 1


Code (334.24) requires that bends in NM cable have a minimum inside radius (cannot turn more sharply than) 5 times the major diameter (larger dimension) of the cable. The general rule is 5 times the diameter of the cable, but for flat ones that's the larger, not smaller dimension. That's hard to do with a hole through a joist unless it's at quite an angle.

Either is fine if you respect that constraint. Cross the space, turn and staple is easier, because you don't have to fiddle with NOT making the turn too sharp where you come out of the hole in the joist. But you also need to avoid turning too sharply before stapling.

2023 revisions clarify that (as with conduit fill) the "diameter" used in prior code revisions is the major diameter of flat/oval cable. Not affiliated with link source.

In any case, keep the bend radius in mind.

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