wmabantajr
Member
How many cubic inches for a 4 AWG conductor? I am using a 4X7X10 box and each 1" conduit that enters it has (2)4AWG(hot) and (1)10AWG(ground) conductors in it.
Volume Allowance Required per 4AWG Conductor
- Thread starter wmabantajr
- Start date
- Status
- Location
- Massachusetts
A 4 AWG requires 0.0 cubic inches of volume allowance.
Was that a typo??
I think larger wires are treated different than #10's and #12's, but you have to count something for them, right?
- Location
- Illinois
- Occupation
- retired electrician
There are no provisions of the NEC that require the use of a volume calculation for conductors larger than #6. Enclosures are sized per the rules in 314.28 for conductors #4 and larger.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Those are weird dimensions for a box. I assume you mean 7x10 by 4 " deep???? Also what direction is the conduit coming in and going out? Is a straight pull or angle pull. I am betting that you are fine either way assuming 2 conduits
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Volume allowance assumes that the NEC cares about how much volume the box has, truth is after you go larger than #6 it doesn't care about volume only that you follow the 6X and 8X rules mentioned in Don's post.
wmabantajr
Member
Not totally clear on the 6X and 8X rule. For (2)4AWG(hot) and (1)10AWG(ground) conductors in 1" conduit would I use 6 cubic inches(6X 1" conduit)? For 4/3 MC cable would I use 4.5 cubic inches(6X 3/4" conduit)? I am using a 7"X10"X4"deep box.
- Location
- Illinois
- Occupation
- retired electrician
There are no cubic inches in the large conductor box sizing rules. The number are inches between the conduit and the enclosure walls or between the conduits. For the "conduit" size where cables are used, you use the minimum size conduit that the code would permit for the size and number of conductors that are in the cable. You do not use the size of the cable connector.
is that a receptacle installed in the side of that junction box? (if so, it's not to code)
314.16 states 'Boxes and conduit bodies enclosing conductors 4 AWG or larger shall also comply with the provisions of 314.28.'
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take a look at this http://ecmweb.com/code-basics/sizing-junction-boxes
- Location
- Illinois
- Occupation
- retired electrician
What part of 314.16 applies to conductors #4 and larger?
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- Location
- Massachusetts
What section is being violated?
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
I suppose someone could try and push 406.5, but I wouldn't.
- Location
- Illinois
- Occupation
- retired electrician
There is nothing in 314.16 that applies to installations of conductors #4 and larger. The word "also" in the section that you quoted should not be there.
CMP 9 does not agree.
red = text to be deleted
The only problem with the panel statement is that there is no way to apply the "sufficient size" wording. It is vague and unenforceable. The enforceable rules for boxes with conductors #4 and larger are found in 314.28.
314.16(C)(2) I believe applies to conductors # 4 and larger.
can 4 AWG be spliced in conduit bodies?
I'm too lazy to look it up, but for conduit bodies, I believe there is specific language about having enough space if conductors are spliced in a conduit body.
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
314.16(C)(2) With Splices, Taps, or Devices. Only those conduit
bodies that are durably and legibly marked by the manufacturer
with their volume shall be permitted to contain
splices, taps, or devices. The maximum number of conductors
shall be calculated in accordance with 314.16(B). Conduit
bodies shall be supported in a rigid and secure manner
- Status