Electrical question about "bundling"

[Joe_88k5]

How exactly is bundling defined? I'm rewiring my garage because the previous owner's work was just scary. Right now all the romex is exposed on the studs but I plan on sheeting the walls in the near future and want to keep the wiring outside the walls for ease of making future changes. I was thinking of making a cable tray along the ceiling and dropping conduit to surface mounted boxes.

My question is how tight of a space do the cables have to be running through to meet the conditions for bundling? For example, I'm going to have about 5-6 runs of romex on the most "congested" wall. I know there's a limit of 9 current carrying conductors run together for more than 24" that determines bundling, but is that if all the cables are tied together (ie zip tied) or if they're just confined in the same space? Does this fall under the 20% fill rule? If all the wires need to maintain separation, what is that distance? I've been trying to learn as much as I can about the NEC but I'm still kinda confused about this one.

Thanks!

[Shram]

ldn't worry about it. But all inspectors look at it different. I would just ask him if you are worried.

[Joe_88k5]

Yeah I think I've been overly worried about it. I did some reading on an electrical forum and the way I understand it is that if I use something like cable stackers to physically keep the wires separated inside the tray/wireway I should be ok. It looks like as long as the wires are kept separated it's not considered bundling.

All I'm really trying to do is avoid having to put up 5 or 6 separate runs of conduit along the top of the wall or ceiling since it would look like crap and be a huge PITA.

[Joey D]

Buy some 3M Stackits and run them along the top beam and drop down to all your outlets as needed in conduit like you said. They hold 8 romexes per stackit and you could do 2 rows of them if needed. Very cheap and very neat looking if installed neatly