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box fill calculations #57144
10/05/05 10:50 PM
10/05/05 10:50 PM
N
ngoody24  Offline OP
Member
Joined: Sep 2005
Posts: 33
pace,FL, United States
Hi every one im new to your website finding it very helpful though. I have a question about simple box fill calculations.

When figuring the number of conductors in the box for example 2 duplex plugs, 2 cable clamps , 4 #12 wire 2 grounding wires, and 1 bonding jumper.
would the total #12 conductors be 12?
see i was reading in the code book where 314.6(b)(4) and dont realy get this one are they saying the device itself (counts as one)or what? And are the jumpers counted at all? Hey thanks for hearing me out.

Work Gear for Electricians and the Trades
Re: box fill calculations #57145
10/05/05 11:01 PM
10/05/05 11:01 PM
D
DSpanoudakis  Offline
Member
Joined: Aug 2005
Posts: 89
Astoria, Queens, N.Y.C.
This is the 1st time attacking this, apprentice here, I'd say 8 in total. The grounding wires aren't counted as current carrying. So 2 for the 2 duplex, 2 for the clamps, and 4 for the #12s. I may be wrong though, but it's how I'm interpreting it to say. Someone correct me, I think I am wrong. :P

Re: box fill calculations #57146
10/05/05 11:04 PM
10/05/05 11:04 PM
N
ngoody24  Offline OP
Member
Joined: Sep 2005
Posts: 33
pace,FL, United States
check out 314.16(b)(5) if you can

Re: box fill calculations #57147
10/05/05 11:13 PM
10/05/05 11:13 PM
G
gfretwell  Offline

Member
Joined: Jul 2004
Posts: 9,251
Estero,Fl,usa
4 #12s = 4 @ 2¼ cu/in
2 devices = 4 @ 2¼ cu/in
2 clamps = 2 @ 2¼ cu/in
all the grounds = 1 @ 2¼ cu/in

I get 11 x 2¼ = 24.75 cu/in


Greg Fretwell
Re: box fill calculations #57148
10/05/05 11:19 PM
10/05/05 11:19 PM
D
DSpanoudakis  Offline
Member
Joined: Aug 2005
Posts: 89
Astoria, Queens, N.Y.C.
Ok, it shows 2.25 in.3 for #12. Since you have 4, that's a total of 9. Clamps seem to be only for 1 clamp, rated at wire size so, clamps @ 2.25. 1 device = 2, you have 2. So 4 x 2.25, so that equals to 9, or it seems to be that way. For the grounding, you take the largest, which seems to be a #12 in your case, at 2.25 as well. It seems that jumpers and pigtails don't count.

So, if I'm not mistaken, 9 + 2.25+ 9 + 2.25 = 22.5 in.3 In terms of box fill, I'm going for 10?

Again, my first attempt, don't quote me on it.

[This message has been edited by DSpanoudakis (edited 10-05-2005).]

Re: box fill calculations #57149
10/05/05 11:24 PM
10/05/05 11:24 PM
D
DSpanoudakis  Offline
Member
Joined: Aug 2005
Posts: 89
Astoria, Queens, N.Y.C.
gfretwell,

314.16(B)(2):

Where one or more cable clamps, whether factory or field supplied, are present in the box, a single volume allowance in accordance with Table 314.16(B) shall be made on the largest conductor present in the box. No allowance shall be required for a cable connector with it's clamping mechanism outside the box.

Doesn't this mean that even if there's 2 clamps in 1 box, it still counts as 1? The first/opening sentence, I interpret this way, as being 1, since the opening lines are, "Where one or more...".

No?

Re: box fill calculations #57150
10/05/05 11:28 PM
10/05/05 11:28 PM
N
ngoody24  Offline OP
Member
Joined: Sep 2005
Posts: 33
pace,FL, United States
yes i would say your right on the money on the clamps

Re: box fill calculations #57151
10/05/05 11:30 PM
10/05/05 11:30 PM
N
ngoody24  Offline OP
Member
Joined: Sep 2005
Posts: 33
pace,FL, United States
see i was reading in the code book where 314.6(b)(4) and dont realy get this one are they saying the device itself (counts as one)or what?

Re: box fill calculations #57152
10/05/05 11:33 PM
10/05/05 11:33 PM
N
ngoody24  Offline OP
Member
Joined: Sep 2005
Posts: 33
pace,FL, United States
im pritty sure 10 would be your answer ????

Re: box fill calculations #57153
10/05/05 11:41 PM
10/05/05 11:41 PM
G
gfretwell  Offline

Member
Joined: Jul 2004
Posts: 9,251
Estero,Fl,usa
I never really thought about it but I suppose it does say "one or more".
If you don't count them all why count any of them?
On the other hand they don't really take up much room.
Let's see what everyone else says.


Greg Fretwell
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