Pullbox sizing over 1000 volts

[Anestle]

I need to size a pullbox that is for a system that is over 1,000 volt. There are (4) 4'' conduits in 2x2 configuration, and it will be in angle pulls. According to 314.70 (B) (1), the box shall not be less than 36 times the outside diameter, over sheath, of the largest cable or conductor. Additonal distance will be increased by the amount of the sum of the outside diameters, of all other conductor entries through the same wall of the box. I know I will be using 500kcmils conductors; outer diameter will be 1.25in, and there are additonal (11) 500kcmils through the same wall of the box.

This is the calculation I have:
1.25*(36) + (1.25)(11) = 58.75''

From the calculation I know the dimension should be at least 5' X 5', is there a standard pullbox size for that dimension? And how do I calculate the depth of the box?

 

[kingpb]

No big deal, but the reference is 314.71 not 314.70.

The first dimension from the entrance to the opposite wall is the 60" as calculated.

So, if the conduits come into the bottom, the box needs to be 60" tall. Since they exit to the left or right, the distance between those conduits and the opposite wall is also 60".

However, that does not cover the distance required by 314.71 (B)(2). In that case it is 36 x the OD; or 36 x 1.25" = 45" between entrance and exit conduits. This should not dictate size of box, but more of where they are installed.

Your probably looking at something like a 60" x 72" x 24" deep. Maybe like $1000.