Box Fill

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Brayton

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How come wire nuts are not included in box fill calculations?

It seems to me the wire nut factor should be somehow included in these calculations.

Brayton
 
Re: Box Fill

Perhaps they already are: wires that pass through a box without junctions are counted as one, not two, even if there is a loop equivalent to two 6" lengths.
 
Re: Box Fill

What bugs me is that a single pole switch counts the same as a GFCI receptacle. A box in compliance for fill gets real crowded when you try to put a GFCI in it.
 
Re: Box Fill

314.16 Number of Conductors in Outlet, Device, and Junction Boxes, and Conduit Bodies.
Boxes and conduit bodies shall be of sufficient size to provide free space for all enclosed conductors. In no case shall the volume of the box, as calculated in 314.16(A), be less than the fill calculation as calculated in 314.16(B). The minimum volume for conduit bodies shall be as calculated in 314.16(C).
The provisions of this section shall not apply to terminal housings supplied with motors.
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These sizes are the minimum, nothing is stopping any of us from usig bigger boxes when we know from experience that GFCIs or dimmers or wind back timers all take up a bunch of space.

You can fit a dryer receptacle in a single gang box but experience tells me it fits easier in a two gang box. :)
 
Re: Box Fill

I agree with john and iwire,

A dimmer switch and a GFCI receptacle count the same as a single pole switch for box fill.

(You snuck in before me iwire)

Chris

[ January 05, 2006, 01:25 PM: Message edited by: raider1 ]
 
Re: Box Fill

Originally posted by LarryFine:
Perhaps they already are: wires that pass through a box without junctions are counted as one, not two, even if there is a loop equivalent to two 6" lengths.
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A looped conductor would have to be less than 12" to only count as one conductor. Take a look at 314.16(B)(1).
 
Re: Box Fill

Actually LarryFine, I believe that your assertion
wires that pass through a box without junctions are counted as one, not two, even if there is a loop equivalent to two 6" lengths.
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is incorrect.

Article 314.16(B)(1) states: Each conductor that originates outside the box and terminates or is spliced within the box shall be counted once, and each conductor that passes through the box without splice or termination shall be counted once. A looped, unbroken conductor not less than twice the minimum length required for free conductors in 300.14 shall be counted twice. The conductor fill shall be calculated wsing Table 314.16(B). A conductor, no part of which leaves the box, shall not be counted.
 
Re: Box Fill

Larry was close. He should have said less than 2-6" lengths. Then it would only count as one conductor.
 
Re: Box Fill

Originally posted by infinity:
Larry was close. He should have said less than 2-6" lengths. Then it would only count as one conductor.
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Yeah, that's it! :eek:


Edit: Hey, I found an excuse for my error! We're still on the '99 NEC, and the sentence about the 12" loop is not in 370.16(B)(1). (This is where the box-fill calculations are in the '99)

Additional edit: For that matter, in the '02 NEC, where this section is indeed 314.16(B)(2), the 12" loop is also not mentioned; it must be an '05 change.


This strengthens my past assertions that mentioning which code cycle one is quoting is important.

[ January 05, 2006, 11:06 PM: Message edited by: LarryFine ]
 
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