box fill service wires

[Trouyano]

How big should a box be (cubic inches) for (6) 4/0 and (3) 2awg. Table 314.16a only goes down to 6awg. I did some creative math formulas and got 367.5 cubic inches. I believe 12x12x4 should cover it.

Thank you

 

[jumper]

You size the box by the number and size of the conduits entering the box. 314.28

Here is a good article:
http://ecmweb.com/nec/code-basics/sizing_junction_boxes/

 

[infinity]

I applaud your creativity but what you've come up with has little to do with the code.

 

[DARUSA]

Straight pull or angle pull?

 

[jumper]

I applaud your creativity but what you've come up with has little to do with the code.

Every time I get creative, I get a red tag and a lecture from the inspector.:grin:

 

[jusme123]

You size the box by the number and size of the conduits entering the box. 314.28

Here is a good article:
http://ecmweb.com/nec/code-basics/sizing_junction_boxes/

and what if there cables?

 

[jumper]

and what if there cables?

I use the same numbers for cables based on connector size. Code? IDK. It seems to keep inspector happy. Too tired to look it up.

 

[rexowner]

and what if there cables?

You would use the minimum size conduit that would hold the wires
in the cable. E.g. if you had 4 x 1/0 in a cable, you would use a 1-1/2
conduit and size accordingly.

More precise wording in 314.28(A).