314.16 box fill?

[Dusty Steele]

This is more of a general question about box fill. I have a 4" X 4" X 4" junction box with a hinged cover. There aren't any visible markings as to what the cubic inch allowance is for this box. The conductors entering into the box are: 6) #8awg & 5) #10awg. Which calculates to 30.5 cubic inches. There are only 3) #10awg EGC'S which has been captured in the "5) #10awg". The largest 4 square (2 1/8" deep) listed in Table 314.16(A) is only 30.3 cubic inches. Does anyone have any code references or standards that will help me out with the question of how do I calculate and what is the allowable box fill?

 

[retirede]

This is more of a general question about box fill. I have a 4" X 4" X 4" junction box with a hinged cover. There aren't any visible markings as to what the cubic inch allowance is for this box. The conductors entering into the box are: 6) #8awg & 5) #10awg. Which calculates to 30.5 cubic inches. There are only 3) #10awg EGC'S which has been captured in the "5) #10awg". The largest 4 square (2 1/8" deep) listed in Table 314.16(A) is only 30.3 cubic inches. Does anyone have any code references or standards that will help me out with the question of how do I calculate and what is the allowable box fill?

If the dimensions are outside and the wall thickness is 1/16”, you end up with about 58 CuIn. Measure your box and calculate it.

 

[WD40]

Aside from answering a test question I have found the box fill is a lot more wire than I will put in a box. The devices have gotten much larger and you cannot fit them into a box at max fill.

I have never understood how they regulate just part of the puzzle, the box, our wires that go in the box but not the device displacement.
Either delete box fill from the code or mark devices with a displacement and regulate the whole puzzle.
But I also don't understand old residential 1-gang boxes at all, the old ones here had to have been installed with child labor using tiny tools, I see these old black metal ones that barely fit two old 14 K&T or 14/2 BX rubber wire and one two prong device, they will be perfectly done, sometimes soldered splices until someone tries to shove a GFCI in there and wonders why the ground pin is energized.

 

[Dusty Steele]

This is more of a general question about box fill. I have a 4" X 4" X 4" junction box with a hinged cover. There aren't any visible markings as to what the cubic inch allowance is for this box. The conductors entering into the box are: 6) #8awg & 5) #10awg. Which calculates to 30.5 cubic inches. There are only 3) #10awg EGC'S which has been captured in the "5) #10awg". The largest 4 square (2 1/8" deep) listed in Table 314.16(A) is only 30.3 cubic inches. Does anyone have any code references or standards that will help me out with the question of how do I calculate and what the allowable box fill?

If the dimensions are outside and the wall thickness is 1/16”, you end up with about 58 CuIn. Measure your box and calculate it.

I've been unable to find the code article that allows for actual dimensions to be used to determine box fill. My initial thought was the box was sized incorrectly based on 314.28. Do you have a code reference or a standard for the method you are applying (eg.,NEMA)?

 

[retirede]

This is more of a general question about box fill. I have a 4" X 4" X 4" junction box with a hinged cover. There aren't any visible markings as to what the cubic inch allowance is for this box. The conductors entering into the box are: 6) #8awg & 5) #10awg. Which calculates to 30.5 cubic inches. There are only 3) #10awg EGC'S which has been captured in the "5) #10awg". The largest 4 square (2 1/8" deep) listed in Table 314.16(A) is only 30.3 cubic inches. Does anyone have any code references or standards that will help me out with the question of how do I calculate and what the allowable box fill?

I've been unable to find the code article that allows for actual dimensions to be used to determine box fill. My initial thought was the box was sized incorrectly based on 314.28. Do you have a code reference or a standard for the method you are applying (eg.,NEMA)?

Volume is basic geometry. It does not need to be defined in the code. No different than any other basic unit or dimension.

 

[wwhitney]

I have a 4" X 4" X 4" junction box with a hinged cover. There aren't any visible markings as to what the cubic inch allowance is for this box.

Since 4x4x4 is not a standard size listed in Table 314.16(A), that sounds like a violation of the first sentence of 2023 NEC 314.16(A)(2): "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(s). "

Cheers, Wayne

 

[infinity]

I'm thinking hinged cover Article 312 cabinet.