anyone know a simple way to calculate size of j box

[jsbeard]

I have 3- 4" with 4- 500's feeding in the back and the same thing going out the top. would a 24x24x10 do it

 

[augie47]

There's no "simple way" as the layout of your conduits make a difference (Number of conduits in a row, distance between conduit entries, makes a difference).
It is highly unlikely 24" will work for the 3 entering the top to the opposite wall.
24" wide should not be necessary (again depending on your conduit layout) and 10" deep is not necessary.
Have you looked at 314.28 ?

 

[cowboyjwc]

If it looks to full, it probably is. But that's just from an inspectors stand point.

 

[don_resqcapt19]

If it looks to full, it probably is. But that's just from an inspectors stand point.

In this case there is no "fill" issue. That only applies when the conductors are #6 and smaller.

The issue we have here is the space between the conduits that contain the same conductor and the bending space for the conductors based on the exception for angle or U pulls.

 

[eHunter]

If it looks to full, it probably is. But that's just from an inspectors stand point.

The KISS method, I like it.
Kind of like if it is too hard to work with, work in or work on it is too small.

 

[cpinetree]

Will this help

Will this help

link to J box calculator: http://www.ite-engineering.com/cgi-bin/pBox.pl

 

[cowboyjwc]

In this case there is no "fill" issue. That only applies when the conductors are #6 and smaller.

The issue we have here is the space between the conduits that contain the same conductor and the bending space for the conductors based on the exception for angle or U pulls.

The OP also said, Jbox, what he really meant then was, pull box.

 

[don_resqcapt19]

The OP also said, Jbox, what he really meant then was, pull box.

It doesn't matter what it is called. There are no volume calculations for conductors #4 and larger.

Yes, I am aware that 314.16 says it applies to the larger conductors, but there is no information in the code that lets you apply it.