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.

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

check out 314.16(b)(5) if you can

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

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).]

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?

yes i would say your right on the money on the clamps

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?

im pritty sure 10 would be your answer ????

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.

Well the same thing with the grounding conductor, even if it's 4 grounds in there, it's still 1. I guess the clamps will apply the same concept.

I believe the answer is 10 #12 conductors.


Peter

314.16 (B) (4): For each yoke or strap containing one or more devices or equipment, a double volume allowance in accordance with table 314.16 (B) shall be made for each yoke or strap based an the largest conductor connected to a device(s) or equipment supported by that yoke or strap.

Simply stated you count 2 wires for each yoke.

Chris

since the grounding conductor on the device originates outside the box it is counted a .....1, this counts as an additional EGC...250.146 and 316.16(B)(5) any jumpers that stay in the box are not counted

total is therefore ....11

togol,

Good observation, but I think you are referring to an additional IG grounding conductor.

I count...10

[This message has been edited by Redsy (edited 10-06-2005).]

Redsy.
....yep there it is,

I also typed the wrong reference ....should be ....314.16 (B)(5)
but it does seem to contradict ......(1) of the same section !