Code for bundling romex in household AC

[cebury]

A little off-topic but hopefully an easy answer.

Is there NEC code limiting close placement, or bundling, of several Romex 20amp wiring (for household ac) very close together at the down drop location into the panel? For example fitting several new circuits through one hole in the wall top plate, or down one conduit surface mounted, as they go down and fed into the panel. I would assume not as the few I've seen have all existing wiring bundled down one hole, but I don't know if new rules have superceded since those homes were built.

An electrician and I added two circuits a few weeks back and it was a pain dealing with the limited attic space at the edge of roof overhang. The shingles and osb will soon be removed just above the panel, making it easy for me to drill through the top plates and pre-push wires down the same area. He can come later and do the drops and panel tie-in without the major headache. Coordinating with electricians is nearly impossible right now as their lead times are a month+.

[emartin00]

There is a limit to the number of wires you can put inside conduit. You can find charts online. Other than that, I can't think of any requirements.
I am not a licensed electrician, so don't just take my word for it.

[cebury]

Looks like this will be one of those how closely AHJ inspects and if any bundling deration applies, or spacing required, per the NEC. Even though the holes would only be 3" thick, the space down the wall to the panel is over 24" and fiberglass insulated. Don't know if they will consider that bundling or not.

I was merely hoping to drill two 1/2" holes into the top plates and put two #12 yellow romex down each of them. Hoping at most it'd require a bushing or something.

[inetdog]

When you run several pieces of NM (generic for Romex (TM)) together in a such a way that "spacing is not maintained" (typical weasel words from the NEC) you have to apply the same capacity derating that you would apply for wires in the same conduit. This is referred to as "bundling" and is generally interpreted to allow close runs for up to 24" at a time and for several runs of NM to go through the same hole in a stud or top plate without requiring adjustment. But if the hole is filled with fire caulk or other insulating material the ampacity derating is triggered regardless of length.
The fiberglass insulation around the bundle makes it worse and the AHJ is more likely to complain because of that.
Just space the runs 2" or more apart after they come out of the hole and you should be OK. Same stud bay should be fine.

[acamato]

Plastic stacking staple

After the OP comes thru the top plate, can he use a plastic stacking staple and not have to dereate the cables. The staple secures up to 5 cables along the stud.

[cebury]

After the OP comes thru the top plate, can he use a plastic stacking staple and not have to dereate the cables. The staple secures up to 5 cables along the stud.

I have plenty of these from a different project. Is this what you're referring to?

Do I need a bushing for the hole?

Guess If I do the separation, I could put all 4 down one larger hole as long as it isn't more than 25% the width of the 2x4?

[inetdog]

I have plenty of these from a different project. Is this what you're referring to?

Do I need a bushing for the hole?

Guess If I do the separation, I could put all 4 down one larger hole as long as it isn't more than 25% the width of the 2x4?

There may not even be a problem with bundling the runs if none of the are close to amperage limit of the wire size in the first place. Bundling is not prohibited, it just forces you to use the same adjustment factors to ampacity that you would for more than three Current Carrying Conductors (CCCs) in a single conduit.

[cebury]

There may not even be a problem with bundling the runs if none of the are close to amperage limit of the wire size in the first place. Bundling is not prohibited, it just forces you to use the same adjustment factors to ampacity that you would for more than three Current Carrying Conductors (CCCs) in a single conduit.

Thank you everyone for the help.

I went ahead and put everything down 2 holes. I spoke with a long-time electrician yesterday and he informed me the local inspectors won't bother de-rating anything. They never care to look at the top plate penetrations especially since it will be coming into an the joist space -- even with the insulation. He said if they "decide to care" and see it, they'll start giving you a hard time and won't approve it for whatever reason they choose, but they won't bother with de-rating requirements.

If it was de-rated, I'd be fine on all the circuits except for the 2 x20amp bathrooms pulled for combo exhaust/light/heaters. I was pulling 12-2 nmb for all the circuits and expected 15amp breakers on all of them except the bathrooms.