I'm trying to figure out what junction box to use for a ceiling fixture. There is presently no box, and I have limited space (depth and width, in particular). The box will contain: --one 12/2 conductor, probably clamped inside the box --wires for the light, including hot, neutral, and stranded ground --a mounting strap for the light --a pigtail for grounding the strap --wire connectors (3--hot, neutral, ground) Based on 314.16, how many volume allowances is this? How do you count it? Also, is there any problem using a rectangular box for a ceiling fixture. I understand that 314.27 specifies that boxes used for lights shall be designed for that purpose. Do rectangular boxes qualify?

Can I run my sheathed romex cable through the same holes in the studs that my copper water pipes are run through ?