When sizing a pull box with a three inch conduit and a two inch conduit on the left side and a two inch on the right side and a three inch on the bottom, article 314.28 (A) (1) states to use the largest conduit. Is that to asume I use the largest conduit with a straight pull, which would be the 2 inch or would I use the three inch which is actually an angle pull for the calculation?
Pull box sizing
- Thread starter Bud Hill
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cschmid
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- Northern cold country
I read differently is this what your book says..
314.28 Pull and Junction Boxes and Conduit Bodies.
A(2) Angle or U Pulls, or Splices. Where splices or where angle or U pulls are made, the distance between each raceway entry inside the box and the opposite wall of the box shall not be less than six times the metric designator (trade size) of the largest raceway in a row. 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.
314.28 Pull and Junction Boxes and Conduit Bodies.
A(2) Angle or U Pulls, or Splices. Where splices or where angle or U pulls are made, the distance between each raceway entry inside the box and the opposite wall of the box shall not be less than six times the metric designator (trade size) of the largest raceway in a row. 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.
chris kennedy
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- 60 yr old tool twisting electrician
Looks to me like he has a 2" striaght pull.cschmid said:
8?3=24
hardworkingstiff
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- Wilmington, NC
chris kennedy said:
Wouldn't it be 8X2=16?
But...... 3X6=18 for the 90 degree pull, plus the 2" in the same row would (on the left side) would make it 20" ?
chris kennedy
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- Miami Fla.
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- 60 yr old tool twisting electrician
hardworkingstiff said:
Maybe Lou but the art. I quoted said 'largest conduit'.
stickboy1375
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- Litchfield, CT
hardworkingstiff
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- Wilmington, NC
chris kennedy said:
OK Chris, I see your point (I don't believe I agree with it). That article was dealing with straight pulls and the 3" is not a straight pull. Based on this reasoning though, I'm not sure what I said is accurate either.
It will be interesting to see what develops here.
cschmid
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- Northern cold country
three inch conduit and a two inch conduit on the left side and a two inch on the right side and a three inch on the bottom,
Chris how do you get that as a straight pull..lets see one 3" on left and a 3" on the bottom..Largest conduits are 3" angle..I get a 20" box..
6X3=18+2=20 angel pull
Chris how do you get that as a straight pull..lets see one 3" on left and a 3" on the bottom..Largest conduits are 3" angle..I get a 20" box..
6X3=18+2=20 angel pull
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KentAT
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For a straight pull, I don't believe the "largest raceway" referred to in 314.28 (A)(1) includes raceways entries not involved in the straight pull for which the calculation is being performed. I know this is an interpretation and not spelled out clear enough in the code.
With that in mind, minimum width would be the larger of:
Straight pull = 8x2=16"
Angle pull = 6x3"=18" + 2" adder = 20"
Minimum width would be 20".
Height would be: an angle pull, 6x3"=18"
Minimum height would be 18".
Also part of 314.28 (A)(2), the minimum distance between the 3" entries is 6x3"=18".
With that in mind, minimum width would be the larger of:
Straight pull = 8x2=16"
Angle pull = 6x3"=18" + 2" adder = 20"
Minimum width would be 20".
Height would be: an angle pull, 6x3"=18"
Minimum height would be 18".
Also part of 314.28 (A)(2), the minimum distance between the 3" entries is 6x3"=18".
mdshunk
Senior Member
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- Right here.
Unless you're getting something specially fabricated, you're probably going to end up using the same box no matter which way you do your calcs due to standard off the shelf box sizes.
Pull box sizing
Thank you very much for all your inputs. As in my apprentice class, I get many different interpretations. I have the same reasoning as KentAT. The three inch is not involved in the straight pull so why use it in a straight pull calc which would be 24 inches. I know I would probably just use a 24"X24" box because it is a standard that I would probably find on the shelf of a good parts house, but I was asking a question of some students for the 'minimum size box allowed by the code'. Understanding that you have to use the largest calc you come up with for the various pulls, I would agree with KentAT's summary. I have asked the AHJ for my area though and he said I need to use the 3" in the straight pull calc because the way 314.28 (A) (1) is worded. Thanks again for your inputs.
Thank you very much for all your inputs. As in my apprentice class, I get many different interpretations. I have the same reasoning as KentAT. The three inch is not involved in the straight pull so why use it in a straight pull calc which would be 24 inches. I know I would probably just use a 24"X24" box because it is a standard that I would probably find on the shelf of a good parts house, but I was asking a question of some students for the 'minimum size box allowed by the code'. Understanding that you have to use the largest calc you come up with for the various pulls, I would agree with KentAT's summary. I have asked the AHJ for my area though and he said I need to use the 3" in the straight pull calc because the way 314.28 (A) (1) is worded. Thanks again for your inputs.
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