Instructor

[Nutty Professor]

Sizing a pull box that contains both straight and angle pulls. The box has two -3 inch pipes and two -3.5 inch pipes all in a row on the left side of the box. One 3 inch pipe and one 3.5 inch pipe are straight pulls and go out the right side. One-3 inch pipe is an angle pull and goes out the top. One-3.5 inch pipe is an angle pull and goes out the bottom. Can someone confim the minimum size pull box for this application. Also my real question would be: When sizing a pull/junction box that contains both straight and angle/upulls we my have pipes in the same row that have applications to both 314.28 (A)(1)&(2).

 

[Dennis Alwon]

Straight Pulls

Angle Pulls

 

[Dennis Alwon]

I come up with 30.5x28

 

[Dennis Alwon]

Here is a better graphic

 

[augie47]

I can't say that I have a definite "read" on this situation. I look at the angle pulls separate from the straight and only count the conduits involved in each, but that may not be the proper way.
To me your straight pull would be 3.5 X 8 + 3" for a 31" dimension.
Your greatest angle pull would be 3-1/2 x 6 + 3 or 24".
I guess an argument could be made that the 2nd conduit not be added to the angle pull as it goes out the opposite wall.

I would say 31 x 24, but I could not argue with 31 x 21

 

[Dennis Alwon]

After I posted last image I think 31x21 is correct. You would only have one 3.5 out the bottom and one 3 " out the top. So for the angle I would just use 6x3.5=21

 

[hurk27]

From what I get in the OP is the straight pulls will only require a 28" measurement.
But the angle pull because we are required to add the sum of all the other conduits I.E. 6x3.5+3.5+3+3=30.5" and since this is larger then 28" we must use the 30.5"

314.28(A)(2)This distance shall be
increased for additional entries by the amount of the sum of
the diameters of all other raceway entries in the same row
on the same wall of the box. Each row shall be calculated
individually, and the single row that provides the maximum
distance shall be used.

Also we can't for get the distance between the conduits of the angle pull:

314.28(A)(2)The distance between raceway entries enclosing the
same conductor shall not be less than six times the metric
designator (trade size) of the larger raceway.

Here's a little diagram I make up when doing box sizing calculations:
A is the straight pull
A2 is the angle pull
And C is the distance required between conduits I only figured one.

So the end result is 30.5X21 which we all know will end up being a 32" x 24" as it is an off shelf box size.

 

[hurk27]

I can't say that I have a definite "read" on this situation. I look at the angle pulls separate from the straight and only count the conduits involved in each, but that may not be the proper way.
To me your straight pull would be 3.5 X 8 + 3" for a 31" dimension.
Your greatest angle pull would be 3-1/2 x 6 + 3 or 24".
I guess an argument could be made that the 2nd conduit not be added to the angle pull as it goes out the opposite wall.

I would say 31 x 24, but I could not argue with 31 x 21

There is no requirment to add the other raceways in to the *8 figure on straight pulls only angle, U, and splices which is a lower *6 figure, but you add all the conduits in the same row that is in the same wall (left wall) as it has the greatest sum

314.28(A)(1) Straight Pulls. In straight pulls, the length of the box
shall not be less than eight times the metric designator
(trade size) of the largest raceway.

Now heres one to mull over:
How deep does this box have to be with out any entries in the back?

 

[augie47]

Thanks Wayne.
I forgot Charlie's rule.
It HELPS TO READ the Code and not "think you know what it says"

As far as depth, with no entries out the back, I would think it only needs to be as deep as required by the conduit diameter (locknuts/bushings, etc,)