Hello,

I'm roughing in an addition and adding lighting and receptables (on separate 15 amp circuts) in accordance with NEC. But I cannot find anything that tells me if I can run more than one wire through the holes drilled vertically along the run through 2 X 4 studs (drilled 1 1/4" from the eds of the studs).

Is it acceptable to run more than one wire (from separate circuts) through the same holes? Seems like this is the most sensible way to run the circuits.

Thanks for your help,
Robert

More than two 2 wire cables will be considered as more than 4 current carrying conductors, and will be subjected to derating factors, so the max is two cables run through a hole.

Check with your local inspector to see what he will allow.

I say this is a gray area.

I'm with TK, it's best to consult your inspector.

Another issue just crossed my mind. What are you adding? If it's a bedroom, you may be required to use AFCI's. Just another question to ask your AHJ while you have his ear.

Washington, I do not see this as a gray area.

Bundling of multiple of NM-B cables, AKA Romex, which is what I assume is being installed as this cable is the most popular for home wiring, clearly falls under Section 310.16 (B) (2) Adjustment Factors.

If BX or MC cable is being used, then no, the derating factors do not need to be considered. Not likely that many people are using BX or MC nowadays.

Another issue just crossed my mind. What are you adding? If it's a bedroom, you may be required to use AFCI's. Just another question to ask your AHJ while you have his ear.

Good point. I am adding two stories = an execise room downstairs and office up. I am planning to indeed install an AFC but only on the circuit that contains lighting for the three closets that will be wired for lighting as a safety precaution.

Thanks again for the input.

Robert

I think the ARC Fault would help floor Lamps and Cords better than closet lights(If ceiling or wall mounted)

And if either room could be considered a bedroom by your AHJ, you may be required to comply with current AFCI requirements anyway.

What about smoke detectors? You might want to hardwire those in and tie them to your current smokes. It never seems to end does it!

Never ends. Even after it's done it doesn't end :-)

Smoke detectors are being installed, for sure, but please explain why AFC is better for cords and lamps than ceiling fixtures, which is what I am installing in the closets. Ceiling fixtures with fluorescent bulbs.

No problem on bedroom space restrictions. Neither of these rooms would possibly be used for bedroom space they're just not set up for it. One floor is a sprung floor exercise room the next is totally office space -cabinets, files, etc. They will never be used for bedroom space.

Washington, I do not see this as a gray area.

Bundling of multiple of NM-B cables, AKA Romex, which is what I assume is being installed as this cable is the most popular for home wiring, clearly falls under Section 310.16 (B) (2) Adjustment Factors.

If BX or MC cable is being used, then no, the derating factors do not need to be considered. Not likely that many people are using BX or MC nowadays.

I guess the question would be, could we apply the definition of "Bundled" from NEC 520.2. Then would running NM (Not over 12AWG) be considered bundled based on this definition.

Tk, so you could have 3 sets of romex, if 2 of the sets were travellers?
Only 1 traveller would be Current carrying on each of the 2?

Yes, travelers would constitute that same circuit, so more can be in one hole.

Let's just keep that between you and I.

Get's too confusing trying to explain to DIY'ers the reasons for all of this.

Hey thanks.
Here's one for the other electricians, what are 2 different conditions must be met before you can parallel conductors?
Take Care