Wire fill contradiction

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Dennis Alwon

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Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I was working with a single gang plastic cut in box today. It was stamped as being 14 cu in. It was also stamped that it could handle 9/14's, 8/12's and 7/10's.

What gives? Which do you go by?
I have never seen a 14 cu inch box. I bet it is an 18 cu. in. box. I bet you need glasses also. :grin: What brand is it?
 

Buck Parrish

Senior Member
Location
NC & IN
I was getting ready to say you have an odd ball. I'm sure they make them thier are so many.
But, that box will only handle 2 - 14-2's with ground and one device.
Perhaps it's a two part box. I'm not sure...
 

KentAT

Senior Member
Location
Northeastern PA
But, that box will only handle 2 - 14-2's with ground and one device.
Perhaps it's a two part box. I'm not sure...

..or (3) 14/2 w/g with no device = 7 conductor allowances = 14 cu in, ...BUT Bubba might think of them there as 9 conductors. However, the R.O.B. (Rules of Bubba) have no place being molded on a plastic box.
 
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jaylectricity

Senior Member
Location
Massachusetts
Occupation
licensed journeyman electrician
Think about this for a minute. If you have 9 #14s in that plastic box, you most likely have 3 14/2 romex cables coming in. 3 of the wires will only count as one because those will be the EGC. So you'll have 3 blacks, 3 whites, and 1 ground. #14 occupies 2 cu in of space per the NEC. 7 X 2 = 14

In this situation you would not be allowed to mount a device in the box because that would add 4 cu in to the fill.
 
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Dennis Alwon

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Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
try 314.16(B) for box fill calculations/. 3 x 2 x 2 3/4 is a 14 cu"
That's correct but if you use Table 314.16(A) that box will only allow 7 -#14 not 9. I still think the OP read the numbers in the box wrong or they are printed incorrectly.

The Op also stated an old work 1 gang plastic box. T. 314.16(A) is for metal boxes
 
FWIW I only entered 2 14/2's and it will have a device for a total of 7 allowances. I showed the box to my journeyman and he confirmed what I saw. I think that there was a factory mistake. The box looked a lot more comfortable with 7 #14 allowances than it would have with 9. According to my supply house invoice the box is a Carlon EZ14SO.
 

jaylectricity

Senior Member
Location
Massachusetts
Occupation
licensed journeyman electrician
Did you guys completely ignore my post? You can have 9 wires in there, you just won't be able to have a device, and 3 of the wires will only count as 1 being the EGC.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Did you guys completely ignore my post? You can have 9 wires in there, you just won't be able to have a device, and 3 of the wires will only count as 1 being the EGC.
Yes we completely ignored you. :grin: Seriously , I think we were assuming devices, clamps etc. in that count
 
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