Required Pull-Box size for conduit entry into side of equipment

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For this particular instance I need to show this side entry solution as part of a design drawing and am not implementing it in the field yet.

I am being asked to provide proof that the felx solution or flex with 45 or 90 deg flex fitting will work. Does anyone have any recommendations how I can show some sort of calculation or spacing factor to show that this solution will work in the 8" of space there is to work with?
 
philly said:
I have a piece of equipment that I will be routing conduit down a wall and into the side of the equipment. The piece of equipment is located only 8" from the wall so there is not much room for turning conduits coming down the wall into the side of the equipment. Instead of using an LB or conduit fitting for turning the conduits into the equipment I've decided to use a pull-box between the equipment and the wall.

I have (4) 2.5" conduits coming down the wall with each conduit containing parallel sets of 4/0 conductors. I am going to attached the conduits to the top of my pull-box and used the box to turn the cables into the side of the equipment which the box is attached to.

My question is what specific dimensions the box needs to be. There is only 8" between the equipment and wall so hopefully this 8" is enough horizontal lenghts to turn cables. How about the vertical length or height of this box? Are there any requirements for the box height?
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Is this what you are looking to do?

Box.jpg
 
If it looks like the picture.........

There will be controversy among us due to the the definition and use of "auxilliary gutters", but, it very well might be permissible with your AHJ to mount a 8" wide gutter.. open to the front or rear, a minimum of 24" high {to maintain the required 6 X + (other conduits)} and classify it as an "auxilliary gutter".
(Acceptable to some, not all)
 
philly said:
Yes that is exactly what I am trying to do. Thanks for the drawing!

Where you the box is sown on your drawing I only have 8" between the side of the enclosure and the wall to the left.
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If you can't fit your conduits into the end of an 8" x 8" x 24" wireway, you would need to have a custom box made.

As long as the length meets the 6 times rule, I don't see why it would have to be approved by the AHJ or considered an auxiliary gutter.
 
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tkb said:
If you can't fit your conduits into the end of an 8" x 8" x 24" wireway, you would need to have a custom box made.

As long as the length meets the 6 times rule, I don't see why it would have to be approved by the AHJ or considered an auxiliary gutter.
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So are you saying that the box is 24" high to allow the 6x rule for the (4) 2.5" conduits coming in the top?

Since the box is on the side of the enclosure and is being considered an "auxilary gutter" does it not have to adhere to the 6x rule since there are no conduits coming into the box from the equipment enclosure but it is rather an auxilary gutter? What section of the code covers auxilary gutters?

With your comments above about being able to fit conduits in to the 8x8x24 box are you referring to have enough space at the top of the box to fit the conduits with adequate conduit spacing? If they dont fit would I need to get a custome box that is more than 8" deed to allow spacing of conduits? I guess 8x8x24 is a standard size?
 
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philly said:
So are you saying that the box is 24" high to allow the 6x rule for the (4) 2.5" conduits coming in the top?

Since the box is on the side of the enclosure and is being considered an "auxilary gutter" does it not have to adhere to the 6x rule since there are no conduits coming into the box from the equipment enclosure but it is rather an auxilary gutter? What section of the code covers auxilary gutters?

With your comments above about being able to fit conduits in to the 8x8x24 box are you referring to have enough space at the top of the box to fit the conduits with adequate conduit spacing? If they dont fit would I need to get a custome box that is more than 8" deed to allow spacing of conduits? I guess 8x8x24 is a standard size?
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I don't think you would be able to physically install four 2-1/2" conduits in the end of an 8" wireway. You will need a custom box.
The height size of this box will depend on how you will be entering the side of your equipment.
There is also the restriction of 6 times the size of the largest conduit between the conduits that enter and exit.

(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 or conduit body and the opposite wall of the box or conduit body 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.

Exception: Where a raceway or cable entry is in the wall of a box or conduit body opposite a removable cover, the distance from that wall to the cover shall be permitted to comply with the distance required for one wire per terminal in Table 312.6(A).

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.

When transposing cable size into raceway size in 314.28(A)(1) and (A)(2), the minimum metric designator (trade size) raceway required for the number and size of conductors in the cable shall be used.
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tkb said:
I don't think you would be able to physically install four 2-1/2" conduits in the end of an 8" wireway. You will need a custom box.
The height size of this box will depend on how you will be entering the side of your equipment.
There is also the restriction of 6 times the size of the largest conduit between the conduits that enter and exit.
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I looked at the recommneded spacing for conduits and see that the recommended spacing between (2) 2.5" conduits is 4" So seeing that I had 4" between the centers of conduits and assuming the radius of each 2.5" conduit is 1.5" then this would give 7" of total lenght from end to end of (2) conduits. If I arranged these conduits in a 2x2 arrangement then I would have a 1/2" space around the edge of the box? Do you not think this would work?

So in this case would the 6x times rule refer to and dictate the height of the box? So in other words with (4) 2.5" conduits the height of the box would be 2.5x6 + 2.5 + 2.5 +2.5 = 22.5 with the next standard box size being 24"? Am I correct in saying that we do not need to consider the 6x rule for the 8"between the equipment cable entrance and the side of the box at the wall since the box will be considered a wireway?

Thanks
 
philly said:
I looked at the recommneded spacing for conduits and see that the recommended spacing between (2) 2.5" conduits is 4" So seeing that I had 4" between the centers of conduits and assuming the radius of each 2.5" conduit is 1.5" then this would give 7" of total lenght from end to end of (2) conduits. If I arranged these conduits in a 2x2 arrangement then I would have a 1/2" space around the edge of the box? Do you not think this would work?

So in this case would the 6x times rule refer to and dictate the height of the box? So in other words with (4) 2.5" conduits the height of the box would be 2.5x6 + 2.5 + 2.5 +2.5 = 22.5 with the next standard box size being 24"? Am I correct in saying that we do not need to consider the 6x rule for the 8"between the equipment cable entrance and the side of the box at the wall since the box will be considered a wireway?

Thanks
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A 2 x 2 arrangement of 2-1/2" conduits will be tight but it is feasible.

The calculation is a by row calculation.
So you would have 2-1/2" x 6 + 2-1/2" would be 17-1/2" and would require a minimum of 18" wireway.

There is also a minimum of 2-1/2" x 6 = 15" between where the conduit enters the top to where it exits out the side.
I don't think you would be able to maintain this dimension by using the minimum size wireway of 18"

You will need to use a minimum size of 24” to maintain the spacing between in and out.
(You use pipe size and not hole size for calculations, I am showing the hole size for 2-1/2" conduit.)

Obviously the longer the wireway, the easier it will be to pull and install the wires without damage.
When you order your wireway make sure you order it and the end plates without knockouts.

Drawn with Google Sketchup a free 3D drawing program, check it out.

wireway 1.jpg
 
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The more I look at what I posted, it may not be correct.
What I showed is an angle pull and would require a dimension of 18" to meet the requirement of an angle pull.

What if instead of 4 nipples into the side of the equipment to the wireway, there was a square hole cut out for all of the wires with the edges protected?

Either way I don't see a too much of a problem since this is at the termination and not a pull box in the middle of the run.

Is this a pull box or an axillary gutter for the equipment?
 
tkb said:
There is also a minimum of 2-1/2" x 6 = 15" between where the conduit enters the top to where it exits out the side.
I don't think you would be able to maintain this dimension by using the minimum size wireway of 18"
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Is this distance cited in 314.28?

tkb said:
The more I look at what I posted, it may not be correct.
What I showed is an angle pull and would require a dimension of 18" to meet the requirement of an angle pull.
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Are you suggesting that the 6x rule would apply to the conduits leaving the side of the enclosure and therefore the 8" would be too small?

What if instead of 4 nipples into the side of the equipment to the wireway, there was a square hole cut out for all of the wires with the edges protected?
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The knockout provisions are alreay on the side of the equipment (inverter) and I dont know that the manufacturer would allow a square to be cut into the side.


tkb said:
Is this a pull box or an axillary gutter for the equipment?
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I'm assuming this would be considdered an auxillary gutter for the piece of equipment.
 
philly said:
I'm assuming this would be considdered an auxillary gutter for the piece of equipment.
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If you are entering through the manufacturer's knockouts, I do not see how this would be an Auxiliary Gutter. Your enclosure has done nothing to increase the amount of 'wiring' space internal to the inverter.

I feel that an auxiliary gutter could not be a stand alone enclosure, because it 'replaces' the side of the equipment is is being added to.
 
philly said:
Is this distance cited in 314.28?
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Yes

Are you suggesting that the 6x rule would apply to the conduits leaving the side of the enclosure and therefore the 8" would be too small?
Click to expand...

Yes

What if instead of 4 nipples into the side of the equipment to the wireway, there was a square hole cut out for all of the wires with the edges protected?
Click to expand...

That's what I might do if it were my job.

The knockout provisions are alreay on the side of the equipment (inverter) and I dont know that the manufacturer would allow a square to be cut into the side.
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If I were worried I would use chase nipples.

I'm assuming this would be considdered an auxillary gutter for the piece of equipment.
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That is what I would go on.

While "technically" it may be a violation of 314.28, you also have to ask yourself, "Is it unsafe".
I think the intention of 314.28 is for pull boxes in the middle of a conduit run and not at a termination like your situation.
The wires most likely will not be pulled through all at once, rather be fed through one at a time.

Either way I would install the wireway and say it is better than using LR condulets.
Sometimes you just have to work with what you have.

Your only other options are, move the equipment so there is enough room for a larger box or sweeps, or get different equipment.

Me, I would install the wireway and try to explain to the inspector that we had no other alternatives. Only if he questions it.
 
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kwired said:
It may be out of the question but can you run down the other side of the wall and either LB or pull box there and then go through the wall and into the back of your equipment? Sounds easier if it is acceptable to do so.
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Would this work Philly?

It's a lot easier to use a pull box where you're feeding wire through the back of it rather than through the side of it. Then it might allow you to use a deeper gutter, say 12" instead of 8" making it a little easier to get the 4/0's curved to go through the back.
 
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