box fill by volumn or number

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Bagram Sparky

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A co-worker has stated that he must install a second junction box due to more than 30 wires entering the enclosure. I have read through 314 and can't find a reference to number, only by fill which is what I am accustomed. The junction box is of sufficient size for the number of conductors entering and exiting. I will continue to search for a reference but, I will appreciate your input. Thank you
 
If you just use the table in 314.16 you should be fine even if you exceed 30 conductors.
 
The only place where 30 conductors is the magic number where something changes that I can think of at this time is in 366.22. But this is for ampacity adjustment factors and not for conductor fill, and applies to aux gutters.

You can have up to 30 conductors in an aux gutter without the need to apply adjustment factors of 310.15(B)(3)(a).

You were looking in right place, 314. You did not find anything supporting your co-workers statement because there is nothing in there with a 30 conductor limit of any kind.
 
Is it possible for you and your coworker to both be right at the same time, because some part of the NEC contradicts another part or seems to contradict another part?

If he'll tell you exactly why he thinks he needs another box this may be resolved. Or not. . .
 
G._S._Ohm said:
Is it possible for you and your coworker to both be right at the same time, because some part of the NEC contradicts another part or seems to contradict another part?

If he'll tell you exactly why he thinks he needs another box this may be resolved. Or not. . .
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I could buy that, except I don't know of any section where 30 conductors is the magic number (in general) that says you need a bigger box.

If you have 30 - 14AWG conductors you have 60 cu. in. of space required, and would need a 60 cu. in. box, but that is based on volume of box and volume of installed conductors, not the number of conductors.
 
hope I do this correctly...

hope I do this correctly...

infinity said:
If you just use the table in 314.16 you should be fine even if you exceed 30 conductors.
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That is what I explained as we have a NEMA 3R, 10 X 10 X 4 J Box with 35 conductors, counting the one for EGC. Conductors are a combination of 12 AWG THHN and RHW or similar in the cords. There are no internal clamps or devices. 6 cables are entering the J Box supplying the THHN conductors in the facility.

After reviewing 366.22 I believe you are correct that he is basing his statement on that. I will clarify that tomorrow. Thank you,
 
Bagram Sparky said:
The box is a NEMA 3R, 10 X 10 X 4 with 35, 12 AWG conductors with a combination of THHN and RHW (cords). There are no internal clamps or devices. Thank you,
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Tell your coworker that box can hold 177 - 12 AWG conductors and he will go ballistic on you if he thinks 30 is the limit. You can get 64 in a 6x6x4 box, and be NEC compliant.
 
kwired said:
Tell your coworker that box can hold 177 - 12 AWG conductors and he will go ballistic on you if he thinks 30 is the limit. You can get 64 in a 6x6x4 box, and be NEC compliant.
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So, without hearing 'the other side', is it 'beyond a reasonable doubt' that the OP is correct?
 
G._S._Ohm said:
So, without hearing 'the other side', is it 'beyond a reasonable doubt' that the OP is correct?
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Would be interesting to hear "the other side" but I think "beyond a reasonable doubt" is very near to being reached. Only place I can even guess that the "30 conductors" came from in the OP is the allowable conductor count in aux gutters before ampacity adjustments are necessary, and there is maybe some confusion related to that.
 
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