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According to the National Electrical Code, you can have 4 12/2 nonmetallic sheathed cables through a single bored hole that is fire- or draft-stopped using thermal insulation, caulk, or sealing foam, or where proper spacing is not maintained for more that 24 in.
8 mar 2012 · I still don't see how you can put 4 NM cables thru same bored/drilled hole, that is to be fire-stopped (thermal insulation).... UNLESS drilled hole is considered an actual "raceway", then CCC conductors in each NM cable are derated per 310.15 (B) (2) (A).
22 sty 2018 · The code doesn't directly address how many NM can be run through a bored hole. So, as many as can be installed without damage. As for derating, I would think the 24" or shorter sleeve requirement would apply.
22 lis 2022 · The #14 calc is 25A (90C ampacity) * 70% (8 CCCs) = 17.5A, so still fine on a 15A breaker. For the #10, the calc is 40A * 70% = 28A, still fine on a 30A breaker, but the load is limited to 28A. That's just if you treat the cables in each hole as bundled, which is debatable.
9 kwi 2005 · There are a number of individuals where I work who insist that no more than 3 NM cables can be passed through a bored hole in wood studs. As far as I have researched, there are no NEC requirements for this.
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 (1 1/4 in.) from the nearest edge of the wood member.
2 paź 2009 · There is no NEC code limit to the number of NM cables installed through bored holes in joists. You just need to watch the adjustment factors if the holes are to be fire or draft stopped. Keep in mind that when starting you adjustment in accordance with 334.80 you can start your adjustments at the 90 degree ampacity column.
