Hello there ... I'm adding a 100 amp sub panel and need to run 100' of Romex 4/3 from one side of my basement to the other. Is it against code to run the Romex through some existing holes in my floor joists that have BX cable running through it too? Some of the holes are large enough to accommodate both, but I'm not if that's against any code regulations? I prefer not to have to drill new holes through the joists. Thanks in advance!
Your terms ("large enough" and "accommodate") are too vague to give a solid answer on but the larger question is how much meat is left on the stud after the hole of X" has been drilled.
NEC300.4 said:
(1) Bored Holes. In both exposed and concealed locations, where a cable or raceway type wiring method is installed through bored holes in joists, rafters, or wood members, holes shall be bored so that the edge of the hole is not less than 32 mm (11⁄4 in.) from the nearest edge of the wood member. Where this distance cannot be maintained, the cable or raceway shall be protected from penetration by screws or nails by a steel plate(s) or bushing(s), at least 1.6 mm (1⁄16 in.) thick, and of appropriate length and width installed to cover the area of the wiring.
The major issue will affect is the structure I do not know the situation what you have there now and TarheelTerp gave you a good example as he posted NEC verison and I am sure the Canada is pretty close to this as well.
The other thing when you pull the large Romex cable the issue you will find out pretty fast is they do not like sharp radius bend so please plan it ahead and plan to drill few new holes as needed to.
But there other option but I do not have the NEC code book with me at the moment but with large romex cable like 4/3 NM you can also put right below the joints as well with proper NM size clamp to hold on the joist ( this part I rather run a small 1X4 pine board or simauir so that way it will give you a little more protection ) only if unfinshsed basement otherwise drill it out and go from there.
The floor joists are 4" x 8"'s and some 2" x 8" microllam lvls ... The diameter of the existing holes would allow me to run the Romex through, but it would snug. I would have to take my time to run it through. I considered clamping the cable under the joists, but at some point I need to get back up into the ceiling and I'm not exactly sure what kind of a ceiling I'm going to use down there yet, so I wanted to leave my options open.
Final question, if the diameter of the hole were able to easily fit both cable, is there any electrical code that would prevent it?
Keep in mind that in many/most areas #4cu is not acceptable for a 100A sub-feed. You are limited to a 90A breaker.
Annoying and stupid I know, but it is enforced in places.
Thank you for the info. My electrician mentioned the same thing about the 90amp limitation. Since running #2 Romex would be tough and I want to stay within code, I may have to reduce it.
No code restriction on the two sharing the same hole, but be careful of friction.
I got shocked by a #10/3 Romex cable that a H.O. installed and then later pulled in MC cable in the same holes. The MC cable wore a hole in the jacket and insulation of the Romex.
Mark
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