Angle Pull box

dvcraven0522!

Member
Location
St. Louis
Occupation
Electrical Design
I have a pull box mounted to a CMU wall to feed (2) MCC's at 800 ea. with 3#600kcmil with (8) 4" conduits. Four of the conduits are spare/

I took 6x4"+4+4+4 = 36" for height and width of the box. My question is how to figure the depth. I am thinking I might be able to use the wire bending space on table 312.6(A). For 600kcmil with 3 terminations per phase for a 12"depth.



1712521091999.png
 
Location
Texas
Occupation
electrical Code instructor and mentor
NEC 2023
314.28(A) and(1) Minimum Size. For straight runs, like yours. I think.

So to figure a straight run, the size of the pull box is based on raceways, not conductors.

There is no depth rule mentioned unless you're entering or leaving the box from the back side of it.

Whatever depth you want, you will see when it's calculated that it will appear to be too small.

Remember ,NEC is a minimum standard. So most likely you will want to use a much larger pull box.

So, with four 4inch conduits on each side of the box and feeding your conductors straight thru you will need a
32 inch wide box.


4 inch x 8 inch = 32 inch wide box will satisfy Code. I'd suggest if you have the space available, make it about 4 ft?

No depth is given in 314.28, as long as you can get the locknuts and bushings into the side wall. A 4 inch conduit is about 5 inches over-all with lock nuts and bushings.

Tip, get a box about 8 inch-10 inch deep or more for the depth dimension.
And, maybe wider, too.
Your size 600 kcmil conductors are not easy to deflect (manipulate).

Thanks for reading
Comments accepted
TX+MASTER#4544
 

Strathead

Senior Member
Location
Ocala, Florida, USA
Occupation
Electrician/Estimator/Project Manager/Superintendent
I have a pull box mounted to a CMU wall to feed (2) MCC's at 800 ea. with 3#600kcmil with (8) 4" conduits. Four of the conduits are spare/

I took 6x4"+4+4+4 = 36" for height and width of the box. My question is how to figure the depth. I am thinking I might be able to use the wire bending space on table 312.6(A). For 600kcmil with 3 terminations per phase for a 12"depth.



View attachment 2570992
Are you coming out of the back of the box? If so, then you use the table for one termination. If not, the the depth is just what is takes to fit the two 4" in two rows as drawn, or probably 10", but I would go with 12" anyway.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
3124.28 says that dimension would be based on "one wire per terminal (8") which is less than you need for the actual conduits.
I'm with strathead, I'd go 12"
 
Last edited:

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
When you size the box, don't forget about this part of the rule if the conductors are not being spliced in the box.
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. ...
Compliance with that will often require a much larger box than just sizing the box based on the raceway size.
 
Location
Texas
Occupation
electrical Code instructor and mentor
NEC 2023
314.28(A) and(1) Minimum Size. For straight runs, like yours. I think.

So to figure a straight run, the size of the pull box is based on raceways, not conductors.

There is no depth rule mentioned unless you're entering or leaving the box from the back side of it.

Whatever depth you want, you will see when it's calculated that it will appear to be too small.

Remember ,NEC is a minimum standard. So most likely you will want to use a much larger pull box.

So, with four 4inch conduits on each side of the box and feeding your conductors straight thru you will need a
32 inch wide box.


4 inch x 8 inch = 32 inch wide box will satisfy Code. I'd suggest if you have the space available, make it about 4 ft?

No depth is given in 314.28, as long as you can get the locknuts and bushings into the side wall. A 4 inch conduit is about 5 inches over-all with lock nuts and bushings.

Tip, get a box about 8 inch-10 inch deep or more for the depth dimension.
And, maybe wider, too.
Your size 600 kcmil conductors are not easy to deflect (manipulate).

Thanks for reading
Comments accepted
TX+MASTER#4544
dvcraven0522!

Your image appears to be a side wall drawing of your pull box.
That looks like 4 rows of 2 conduits each on the visible wall and I'm assuming the same on the unseen opposite wall
So, I take that to be a straight pull. I don't see any drawing of a conduit(s) penetrating that wall.
 
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