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Is a pull box needed?

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Buickspec6231

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Good Day Everyone.

I have a question about if I need a pull box and how to properly size it. I am running a length of 1/2 EMT and will have filled with (6) or (8) 12 AWG THHN/THWN conductors that will have close to 360* worth of bends in it from the panel to the junction box. According to my calculations I am below the allowable 360* worth of bends between junctions/pulls , but if I am including my box offsets, I am right at 355*-ish. Everything I can find so far in the NEC gives rules about sizing the pull box for wire sizes 4 AWG or larger (Ref- 314.28 of the NEC). But I can't find anything about sizing the pull box for the 6 AWG and smaller wires. I have no problem putting one in to use, but am not sure I need one and if I do need one, how to properly size it.

Could someone please help steer me in the right direction? I like to try to figure this stuff out and learn what I can. I know I can call my local electrician and have them do everything, but if that was what I wanted to do.... I wouldn't be on Garage Journal asking this question. Thanks for reading along.

Respectfully,

~Dan
 
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teamextreme

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The NEC limit is 9 wires, but that's really pushing it, IMO. If the run is straight and short I might use 1/2", but with 360* of bends and especially if there's any length involved (you didn't mention that) I would definitely upsize to 3/4"
 
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Buickspec6231

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Fasthotrod said:
Good morning, Dan.

Perhaps this article will help:

https://iaeimagazine.org/magazine/2017/01/31/box-fill-calculations/

If you're running 9 or less #12 conductors in 1/2" EMT and are under the 360 degrees, you're okay... but a pull box might make things easier on you for pulling the wire depending on the length of the run.

Hope this helps,

Mark
Click to expand...

Mark, Thanks for the article. It didn't directly answer my questions, but I found a bunch of useful information on it about the box sizing. Good thing about that, is according to what I've read so far, is that I will be well below the limit for any handy box or junction box. I have also decided, along with your suggestion to just put a pull location inline whether it is needed for code requirements or not. Cheap enough to not worry about it.



Jim greengo said:
Where are you thinking about mounting the box,6-8 #12s in a piece of 1/2" is a lot of wire.
Especially if its solid wire.
Click to expand...

Jim, Thanks for the response. There is most likely going to be 6 wires in each conduit. As teamextreme below mentions, the NEC limit for 1/2" EMT is 9 wires if running 12AWG. The conduit is going to be run up the wall on to the roof truss bracing above the panel and then straight runs over to the eave sides to install receptacles for the garage door openers and another 20a receptacle down at a more user friendly height. Garage door openers are 1/2hp 120v drawing a rated 8.0 amps each.

teamextreme said:
The NEC limit is 9 wires, but that's really pushing it, IMO. If the run is straight and short I might use 1/2", but with 360* of bends and especially if there's any length involved (you didn't mention that) I would definitely upsize to 3/4"
Click to expand...

Teamextreme- After thinking about my layout, there are only going to be 6 wires in each 1/2" conduit. The total length of the conduit I was mentioning right now will end up close to 30 feet. There are (3) 90* bends accounting for 270* of the bends. The other *'s of bend are due to offsets from the panel/junctions and a saddle bend over another piece of 1/2" conduit. I'm just going to put a junction box in the line at one of the mounting bracket locations and use it as a straight pull box if needed. For the $5 additional it might cost me, I'm not going to worry about it any more.

At this point I am just trying to sponge in as much info as I possibly can. Thanks for the replies. If anyone else has any additional info that will benefit me, I would greatly appreciate the knowledge.

-Dan
 
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alfredeneuman

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If you are not going to have splices in the box, a "C" type conduit will function just as well for a pull point.
C-45CG.jpg
 
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rburke65

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Canfield, Ohio
“I am looking to 4un a length of conduit”......... what does that mean? Does that me@n 10’ ....? Or does that mean 5000’ ? There’s a reason you don’t write instructions on how to disarm a bomb. I’d be looking at running AT LEAST 3/4” conduit, an$ a Pull box very 100’.
 
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bjcouche

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Ohio
At only 30 feet length, I would think 1/2" should be fine even with that many bends. Another thought, are you sure you need 6 wires? If you are pulling two separate circuits, you only need to pull 1 ground wire sized for the largest circuit (like if you had a 12 and 14awg circuit in the same conduit). I recently pulled 5 12awg conductors through 1/2" emt at 270deg and 75 feet without trouble, I do use stranded though.
Brian
 
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teamextreme

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Buickspec6231 said:
Mark, Thanks for the article. It didn't directly answer my questions, but I found a bunch of useful information on it about the box sizing. Good thing about that, is according to what I've read so far, is that I will be well below the limit for any handy box or junction box.

Teamextreme- After thinking about my layout, there are only going to be 6 wires in each 1/2" conduit. The total length of the conduit I was mentioning right now will end up close to 30 feet. There are (3) 90* bends accounting for 270* of the bends. The other *'s of bend are due to offsets from the panel/junctions and a saddle bend over another piece of 1/2" conduit. I'm just going to put a junction box in the line at one of the mounting bracket locations and use it as a straight pull box if needed. For the $5 additional it might cost me, I'm not going to worry about it any more.

-Dan
Click to expand...

Don't use handy boxes. They are worthlessly small and really should only be used as a dead-end for a switch or outlet, at best, I won't even use them for that unless there's serious space restrictions.

With 6 wires, 30ft and 270* I think you'll be fine with 1/2"
 
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ddawg16

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S. California
As others have mentioned, if only 6 wires, you're fine with 1/2" EMT....

BUT..........

If you think there is any chance you are going to want to run more wires later....and you're using solid 12g wire.....I'd go 3/4"

A whole lot easier to pull and not that much more in cost.....and it will be a whole lot easier to pull more wire at a later date.
 
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grounded-b

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Milwaukee, WI
Pull boxes for smaller conduit are sized by "fill". Cubic inches of volume.

Each #12 conductor requires 2.25 cu. inches of volume.

Each #14 conductor requires 2.00 cu. inches of volume.

If you splice in the box, it counts as (2) conductors ( double the fill )


A 4" sqr by 2 1/8" deep box has an allowable fill of 30.3 cu inches of fill

A 4" sqr by 1 1/2" deep box has an allowable fill of 21.0 cu inches of fill
 
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bergheger3

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Missouri
No you don't need a pull box according the code. But if your length is a long run you should put 1 in the middle of the run.

How close are all of the bends? That also dictates when I install pull boxes, if there a a lot of bends in close proximity then I will install a pull box so the pull is easier.

In your case I would use 3/4" conduit for sure. NEC only allows (9) #12's in a 1/2" EMT conduit I wouldn't recommend any more than 6 and that's even pushing it. Makes for a hard pull especially with the number of bends you have.
 
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matt_i

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SE Michigan
My take is to make it easy on yourself! There's no point in getting to the end of running conduit and have a completely bad day pulling in the conductors, fighting fish tapes, etc. That's supposed to be the easy part of the job. Its the same amount of work to put in the conduit, so if you know its going to be stuffed already, why not go with the larger size...

I'd just use a condulet "C" body that was pictured above. It will have a gasket already.
 
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