# Pull Box size calculation - Parallel conductors



## telsa (May 22, 2015)

It is most unwise to size down to Code minimums.

You'll be much happier with 8" depth -- and no splices.

You've got me corn fused -- as you describe this pull can as being an extremely large LB.

Feeders leave out the back of the can -- enter from over on the side.

In which case 28" x 28" can't possibly be right.

Since this is a MDP feeder -- you're miles ahead to size it for Aluminum XHHW-2... unless you're stuck... and have to use copper.

Don't under-size your grounding//bonding conductor. It has to be sized for the full ampacity of both pipes.


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## MechanicalDVR (Dec 29, 2007)

Using the minimum size pull box is like using a 4' bath tub an adult can fit but it isn't worth the squeeze.


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## Dennis Alwon (May 9, 2009)

I believe you sized the box correctly


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## frenchelectrican (Mar 15, 2007)

TOOL_5150 said:


> I need to size a pull box for some parallel service conductors. I have [2] 4" conduits coming out of the wall, with [4] 500 kcmil conductors in each. Those two conduits will enter the back of the pull box.
> 
> Out of the right side of the pull box, I will have [2] 4" conduits exiting and going to the switchgear, same amount of conductors, same size, and they will be spliced in the pull box.
> 
> ...


Ya pretty close on sizewise but for my question to ya Tool 5150.,, 

How high on the back of the box where the conductors will enter the box ?

I will suggest to get at least 32X32 with 8 or 10 inch depth due you mention splices inside the box that will change the game a little so prepared for that.

If it was *unspliced* runs., I would just use 6 inch depth tub

You have to remember how tight you have to bend those 500Kcm conductors plus splices inside the tub so that the main moot is depth that what get ya.


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## Dennis Alwon (May 9, 2009)

Here is an example of perhaps what Marc is talking about


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## frenchelectrican (Mar 15, 2007)

Dennis Alwon said:


> Here is an example of perhaps what Marc is talking about


Salamat ( thanks ) Dennis for posting that.

Now Tool5150.,,

As you see the photo what Dennis posted and I know you say 4 inches conduits so therefore 4 X 6 = 24 inches so that is the distance if you came in the back of the box and come out on the right side you need minuim of 24 inches distance so the 32 inch box may fit the bill here. 

But I would go with no smaller than 36 inch box to be on safe side. 

I do not know which way you are comming in the back in side by side or up and down setting so that can change the size a little.


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## TOOL_5150 (Aug 27, 2007)

Dennis Alwon said:


> I believe you sized the box correctly


This is all I wanted to know. I just wanted to make sure I sized it correctly according to the NEC.

I agree with everyone else saying to go with a bigger and deeper can. 

The can Ill use if the customer wants to continue with the job will be a 36x36x8

Thanks everyone for your input.


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