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#57144 - 10/05/05 07:50 PM box fill calculations
ngoody24 Offline
Member
Registered: 09/25/05
Posts: 33
Loc: 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.
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#57145 - 10/05/05 08:01 PM Re: box fill calculations
DSpanoudakis Offline
Member
Registered: 08/31/05
Posts: 89
Loc: 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
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#57146 - 10/05/05 08:04 PM Re: box fill calculations
ngoody24 Offline
Member
Registered: 09/25/05
Posts: 33
Loc: pace,FL, United States
check out 314.16(b)(5) if you can
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#57147 - 10/05/05 08:13 PM Re: box fill calculations
gfretwell Offline


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Registered: 07/20/04
Posts: 9039
Loc: 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
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#57148 - 10/05/05 08:19 PM Re: box fill calculations
DSpanoudakis Offline
Member
Registered: 08/31/05
Posts: 89
Loc: 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).]
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#57149 - 10/05/05 08:24 PM Re: box fill calculations
DSpanoudakis Offline
Member
Registered: 08/31/05
Posts: 89
Loc: 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?
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#57150 - 10/05/05 08:28 PM Re: box fill calculations
ngoody24 Offline
Member
Registered: 09/25/05
Posts: 33
Loc: pace,FL, United States
yes i would say your right on the money on the clamps
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#57151 - 10/05/05 08:30 PM Re: box fill calculations
ngoody24 Offline
Member
Registered: 09/25/05
Posts: 33
Loc: 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?
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#57152 - 10/05/05 08:33 PM Re: box fill calculations
ngoody24 Offline
Member
Registered: 09/25/05
Posts: 33
Loc: pace,FL, United States
im pritty sure 10 would be your answer ????
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#57153 - 10/05/05 08:41 PM Re: box fill calculations
gfretwell Offline


Member
Registered: 07/20/04
Posts: 9039
Loc: 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.
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Greg Fretwell
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