314.17(C) What does this mean? Part 2

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I called Pass and Seymour about this issue just for fun and they got back to me today. They said the clamp must be counted. The only reason they put the conductor numbers in are for marketing purposes. So do the calcs just as you would any other box with clamps.

So would anybody count a RX connector in a 4" sq. box? Code seems to say it is not necessary and you know that clamp takes up more space then the ones in the P&S boxes. What is confusing is the clamps are there and I assume the cu. in is measured with the clamps there so why must be deduct.

I actually did a crude measure on the 22.5 cu. in box and I got 22.34 without deducting the clamp. Accuracy is not great but it is close.
 
Dennis Alwon said:
I called Pass and Seymour about this issue just for fun and they got back to me today. They said the clamp must be counted. The only reason they put the conductor numbers in are for marketing purposes. So do the calcs just as you would any other box with clamps.

So would anybody count a RX connector in a 4" sq. box? Code seems to say it is not necessary and you know that clamp takes up more space then the ones in the P&S boxes. What is confusing is the clamps are there and I assume the cu. in is measured with the clamps there so why must be deduct.

I actually did a crude measure on the 22.5 cu. in box and I got 22.34 without deducting the clamp. Accuracy is not great but it is close.
Click to expand...

UL says they determine the cu of a box with the clamps removed.
 
Whether or not you're supposed to

Whether or not you're supposed to

I will continue to not count them in my calculations. I make it a point not to max out my boxes, but until they differentiate the volume allowance between a 15A single pole switch and a GFCI receptacle or dimmer, the volume difference with these clamps is hardly worth worrying about. :cool:
 
fishin' electrician said:
I will continue to not count them in my calculations. I make it a point not to max out my boxes, but until they differentiate the volume allowance between a 15A single pole switch and a GFCI receptacle or dimmer, the volume difference with these clamps is hardly worth worrying about. :cool:
Click to expand...

Make a proposal. The CMP is not totally adverse to the idea. Read the panel statement in this one.

_______________________________________________________________
9-42 Log #179 NEC-P09 Final Action: Reject
(314.16(B)(4))
_______________________________________________________________
Submitter: Eric W. Dougan, Louis Perry and Associates
Recommendation: Add new text to read as follows:
?For GFCI receptacles or dimmer switches a triple volume allowance, in
accordance with Table 314.16(B), shall be made for each device based on the
largest conductor connected to the device.?
Substantiation: If the minimum calculated box size (based on existing volume
allowances per NEC) is used for GFCIs and dimmers installation is difficult
trying to push device back into box after wiring.
Panel Meeting Action: Reject
Panel Statement: The volume requirements were increased years ago to
accommodate larger devices because the decision as to what actual device
would be used in a particular box was frequently made long after the rough
inspection and the walls being closed in. The substantiation for this proposal
could be considered in the context of partially reversing that former change and
only applying a double allowance to GFCIs and dimmers, but it is not
sufficient to require a triple allowance for these devices.
Number Eligible to Vote: 12
Ballot Results: Affirmative: 12
_______________________________________________________________
 
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