J-Box Sizing

[DOUG BRUNNER]

I don't do this often enough and could use some help....

I have the following conductors entering a Junction box:

#14 - (48)
#12 - (24)
#10 - (6)
#2 - (16)
#1 - (2)
2/0 - (12)

The box is already in the field, but pictures I've seen make it look like a box of snakes.

It is an 'L' shaped box, not sure of the dimensions, but it appears to be wrong.

1) the installer didn't cutback the conductors
2) the box wasn't size properly.

I understand about sizing based on volumes in 314.16(B) for #6 - #18.
My problem is the proper sizing for the rest of the conductors.

There are splices on all the conductors.

NEC refers to 314.28, do I size the samller conductors first, than the larger conductors, adding the totals to find a volume ?

I am puzzled.

 

[sparkyboys]

go to search and enter j box calu. there is already a thread on this. its very extensive and should be helpful

 

[don_resqcapt19]

314.28 is based on conduit size, not wire size. There is no volume calculation for wires #4 and larger. In most cases the rules for the size of the box based on the conduit size will provide plenty of volume for the smaller conductors.