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Subject - Garage Outlet - Box Fill
qrtetbari A post started by Ryan J on code violations (talking about 314.16 specifically) prompted me to ask this (and I think I'm answering my own question here, but thought I'd run it by you guys):

I have a standard 18 cu in plastic box which indicates that I can have 8 12AWG conductors maximum. I like to make sure things are done right (and safely), so I bought a residential eletrical reference book (which is supposedly based on NEC 2002, so I didn't have to spend lots of $$$ for the actual NEC) that tells me that 12/2 romex (with ground) is really only 2 conductors, so one would assume that I can have 4 cables total running through the box. However, looking up 314.16 on the web, I find out that not only did this book not tell me that I needed to count all ground wires as one additional conductor, but more importantly (which puts me over the top on my installation) is I also need to count the receptacle as 2 current carrying conductors.

So, my current wiring setup in my 18 cu in box is:
Source line = 2 conductors
Feed line to next outlet in daisy chain = 2 conductors
Feed line to a switch = 2 conductors
Total of all ground lines = 1 conductor

which made me think I was safe until I have to count the 2 conductors for the actual receptacle, that now puts me over by one (9) - correct?

Just thought I'd ask before I go out and buy a larger box. Yes, I know I should have bought a double-gang box in the first place, but there was a requirement change from the LOML, which is a completely different topic.

Thank goodness I keep an eye on this forum - you guys really keep me honest!
JimmyDee
quote:
So, my current wiring setup in my 18 cu in box is:
Source line = 2 conductors
Feed line to next outlet in daisy chain = 2 conductors
Feed line to a switch = 2 conductors
Total of all ground lines = 1 conductor

Plus two for the device is 9 conductors @ 2.25 per conductor = 20 1/4ci. Most plastic boxes that are 3 1/2" deep are 22 ci. They will work.
Jim
cs409 u need the 22cu in carlon box or something equal to it,,,its single gang... part number B122A-UPC i think thats the number LOL
qrtetbari Thanks, guys, appreciate the input. I bought a 32 cu in double-gang box last night so I now am definitely covered (and it looks better).

Even with all that room, it's still a bear to get the wires to fit in the box (amazing how stiff 12/2 is when you're trying to squeeze it in). Any tips?
cs409 tip ....practice, practice, and practice LOL
Ryan_J Wjen I teach box fill, I harp on the electricians to get themselves to the point where a box calsulation can be done in less than 5 seconds...literally, 5 seconds. With #14 it is simple. Do it 20 times and you can do it in under 5 seconds.
Electricmanscott One thing that diy's do that kills me is leaving the wires too short. If there is enough length on the conductor it is easier to tuck them into the box.
JimmyDee
quote:
Originally posted by Electricmanscott

One thing that diy's do that kills me is leaving the wires too short. If there is enough length on the conductor it is easier to tuck them into the box.

I like to have 8" from the front of the box. I agree with you.
Jim
David Hyatt I made that statement today, Scott. Told my son the same thing. Another thing The guy who wired these outlets hooked the wires on the screws then did something I have never seen before. He twisted the recpt around and around about 6 times then pushed it into the box and screwed it. Why I don't know. The wires looked like one big #2 AWG going to the outlet.
David Hyatt Jim gave me this link on another thread, it has charts near the bottom of the page about box fill.
http://www.hubbellcatalog.com/raco/RACO_boxes.asp?FAM=RacoBoxes
cs409 thanks for the good sites, and info,,,, even with todays wire cost, leaving 8 or so inchs in the ruff isnt a cost factor,,just gives finish guy something to work with and to stay in code...