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#57144 10/05/05 10:50 PM
Joined: Sep 2005
Posts: 33
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Member
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.

#57145 10/05/05 11:01 PM
Joined: Aug 2005
Posts: 89
D
Member
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

#57146 10/05/05 11:04 PM
Joined: Sep 2005
Posts: 33
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check out 314.16(b)(5) if you can

#57147 10/05/05 11:13 PM
Joined: Jul 2004
Posts: 9,923
Likes: 32
G
Member
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
#57148 10/05/05 11:19 PM
Joined: Aug 2005
Posts: 89
D
Member
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).]

#57149 10/05/05 11:24 PM
Joined: Aug 2005
Posts: 89
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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?

#57150 10/05/05 11:28 PM
Joined: Sep 2005
Posts: 33
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yes i would say your right on the money on the clamps

#57151 10/05/05 11:30 PM
Joined: Sep 2005
Posts: 33
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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?

#57152 10/05/05 11:33 PM
Joined: Sep 2005
Posts: 33
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Member
im pritty sure 10 would be your answer ????

#57153 10/05/05 11:41 PM
Joined: Jul 2004
Posts: 9,923
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G
Member
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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