314.17(C) What does this mean? Part 2

[Dennis Alwon]

Well perhaps it is meant to be counted. I never thought to count it but I use 22.5 cu in boxes so that is rarely a problem. Box says 10- #12 so even with 3 -12/2 cables you are good to go counting the clamp. That is the most that I install. I also have 14/3 and 2- 14/2 cables. That totals 11 and that is what the box states ----

11- 14 gauge wires
10- 12 gauge wires
9- 10 gauge wires

 

[infinity]

Well perhaps it is meant to be counted. I never thought to count it but I use 22.5 cu in boxes so that is rarely a problem. Box says 10- #12 so even with 3 -12/2 cables you are good to go counting the clamp. That is the most that I install. I also have 14/3 and 2- 14/2 cables. That totals 11 and that is what the box states ----

11- 14 gauge wires
10- 12 gauge wires
9- 10 gauge wires

So every box manufacturer that puts the number of condcutors in these boxes is doing so incorrectly? I'm looking at the two that I posted photo's of and their calculation is correct without any clamp deduction. Should we assume that they're all wrong or for the sake of this discussion that those are not really clamps required to be counted towards box fill?

 

[Dennis Alwon]

So every box manufacturer that puts the number of condcutors in these boxes is doing so incorrectly? I'm looking at the two that I posted photo's of and their calculation is correct without any clamp deduction. Should we assume that they're all wrong or for the sake of this discussion that those are not really clamps required to be counted towards box fill?

Well the boxes says 10- #12-- does that mean you can put 4- 12/2 nm cables in with a device. No, you have to count the device as 2 wires, the clamp as 1 the egc as 1 so.... I truly don't know the answer but I can see by the wording in art 314.16(B)(2) that those clamps should be counted.

 

[jumper]

Well perhaps it is meant to be counted. I never thought to count it but I use 22.5 cu in boxes so that is rarely a problem. Box says 10- #12 so even with 3 -12/2 cables you are good to go counting the clamp. That is the most that I install. I also have 14/3 and 2- 14/2 cables. That totals 11 and that is what the box states ----

11- 14 gauge wires
10- 12 gauge wires
9- 10 gauge wires

So every box manufacturer that puts the number of condcutors in these boxes is doing so incorrectly? I'm looking at the two that I posted photo's of and their calculation is correct without any clamp deduction. Should we assume that they're all wrong or for the sake of this discussion that those are not really clamps required to be counted towards box fill?

The issue is squirrelly IMPO.

I purposely made sure I included this statement from the Carlon site.

"This procedure was determined by IAEI and UL. Not everybody agrees to this."

 

[George Stolz]

So every box manufacturer that puts the number of condcutors in these boxes is doing so incorrectly?

Clamp fill is stated in the code as a conductor count - I don't see the conflict.

(2) Clamp Fill. Where one or more internal 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 based on the largest conductor present in the box.

So a clamp is a conductor when it comes to counting conductor fill.

 

[Little Bill]

The issue is squirrelly IMPO.

I purposely made sure I included this statement from the Carlon site.

"This procedure was determined by IAEI and UL. Not everybody agrees to this."

I'll be one of those "not everybody agrees." I personally can't see how the clamp/grip,flap, etc., which only protrudes about 1/16" can be counted the same as a clamp that protrudes maybe 1/2". I'll go along with it being a clamp for box fill purposes, but I don't agree.:happyno:

 

[George Stolz]

Seems to me last time I checked those Carlon "flaps" are more of a nuisance than a metal clamp inside a metal box. At least the metal clamp holds things to the back of the box... :rant:

 

[infinity]

I'm still not buying the fact that all the box manufacturers have imprinted the incorrect data on the inside of the boxes.

 

[Volta]

I'm still not buying the fact that all the box manufacturers have imprinted the incorrect data on the inside of the boxes.

Might not be purely incorrect as much as incomplete. 10- #12 guage wires - "allowances" might be implied.

 

[Dennis Alwon]

Seems to me last time I checked those Carlon "flaps" are more of a nuisance than a metal clamp inside a metal box. At least the metal clamp holds things to the back of the box... :rant:

I totally agree that's why I stated that I did not like those clamps. They often don't have enough pressure to hold a wire.

 

[George Stolz]

I'm still not buying the fact that all the box manufacturers have imprinted the incorrect data on the inside of the boxes.

How is it incorrect data, when the code says to convert clamps to conductors? What wire size would you have the factory deduct for?

I don't know where else to look - the manufacturer says count them, the CMP says count them because the UL says to count them. Why is it so difficult to accept?

 

[Dennis Alwon]

I hate it but I have to agree. With the info given the clamp is a conductor.

 

[jumper]

I'm still not buying the fact that all the box manufacturers have imprinted the incorrect data on the inside of the boxes.

Simple. Carlon does not agree that the volume is effectively reduced by the clamps.

The wire data is purely informational and not required by the NEC. NEC only requires volume.

314.16(A)(2) Other Boxes. Boxes 1650 cm3 (100 in.3) or less, other
than those described in Table 314.16(A), and nonmetallic
boxes shall be durably and legibly marked by the manufacturer
with their volume.

P.S. I know that I have never counted the molded clamps for box fill in these zip boxes either and never got called on it.

 

[Dennis Alwon]

I hate it but I have to agree. With the info given the clamp is a conductor.

I do see what Trevor is talking about. Since the clamp is part of the box and must be used to get any wiring in the box, then why state 10- #12 when in fact you can only use 9- #12. If it were marked with just cu. in it makes sense but when it states # of wires it is misleading.

 

[elohr46]

I do see what Trevor is talking about. Since the clamp is part of the box and must be used to get any wiring in the box, then why state 10- #12 when in fact you can only use 9- #12. If it were marked with just cu. in it makes sense but when it states # of wires it is misleading.

What ever happened to following the manufacture's instructions? If they say you can have 10 #12's in there then that's all you need to know.

 

[infinity]

I do see what Trevor is talking about. Since the clamp is part of the box and must be used to get any wiring in the box, then why state 10- #12 when in fact you can only use 9- #12. If it were marked with just cu. in it makes sense but when it states # of wires it is misleading.

That's exactly my point. :happyyes:

 

[jumper]

What ever happened to following the manufacture's instructions? If they say you can have 10 #12's in there then that's all you need to know.

Manufacture said to deduct for clamps. I already posted that.

 

[Dennis Alwon]

What ever happened to following the manufacture's instructions? If they say you can have 10 #12's in there then that's all you need to know.

But does one of the 10 count as the clamp. We must subtract 1 for the egc and 2 for the device. Do we include the clamp-- that is what this thread is about.

 

[jaylectricity]

How many of these clamps would be required to take up 2-2.25 cubic inches?

 

[jumper]

How many of these clamps would be required to take up 2-2.25 cubic inches?

Does not matter, all clamps in total equal 1 conductor allowance.