Junction / Pull Box sizing

[kpepin]

On a pull box, if I plan on running conduits out of 3 sides, what is the proper method of sizing the box.

example:

All 1" conduits

5 conduits in side A
3 Conduits in side B (straight through)
2 Conduits in side C (90 degrees from A and B)


Do I use 8"+2" = 10" for the 3 that go straight through and 6"+1"= 7" for the 90 degree pull and just use a 10" x 10" box or is there anything else I need to consider? (I would probably use a 12"x12" instead of 10"x10" if 10" was minimum)

 

[dillon3c]

Re: Junction / Pull Box sizing

kpepin,if conductors are 4AWG or larger:314.28

8 x 1 = 8" = on A&B (straight)
6 x 1=6+1=7" on C angle (90 degree)
8 x 8 minumum box (keep in mind of deflection
on the angle pull between the 1" conduits)

If conductors are smaller than #4AWG
see table 314.16(b)cubic inches

[ January 29, 2005, 02:08 AM: Message edited by: dillon3c ]

 

[esox39]

Re: Junction / Pull Box sizing

KPEPIN, You were correct. 10"x7". That is the minimum size, you can always go bigger, so a 10x10 is fine.

 

[dillon3c]

Re: Junction / Pull Box sizing

esox,when has 8x1 ever added up to 10

 

[kpepin]

Re: Junction / Pull Box sizing

For some reason I thought you added the sum of all other trade sizes for straight pulls on top of the x8 multiplier. Thanks.

 

[dillon3c]

Re: Junction / Pull Box sizing

314.28(a)(1) Straight Pulls In straight pulls, the length of the box shall not be less that Eight times of the largest raceway....(No other additions required on a straight pull)