Large Box fill

[Lckwd]

Question: what volume is required in a box to junction 12 #2 Cu conductors and 1 #8 ground. This is acutally 4 #2 cu romexes entering 1 box. I've been thru article 314 and the Ugly's book. Can't come up w/ it.

 

[raider1]

Welcome to the forum.

For juntion boxes containing conductors larger than #4 you need to size the box in accordance with 314.28(A). The box will be sized on the raceways and not on the number of conductors installed in the box.

Chris

 

[Dennis Alwon]

Question: what volume is required in a box to junction 12 #2 Cu conductors and 1 #8 ground. This is acutally 4 #2 cu romexes entering 1 box. I've been thru article 314 and the Ugly's book. Can't come up w/ it.

Have you read 314.28 (A)?

 

[Lckwd]

Yes. IF I was using conduit it would be 1-1/4". Since this application is romex installed free inside the framing, I believe I simply pretend I am using 1-1/4" EMT and size accordingly. Is this correct? TIA.

 

[chris kennedy]

For juntion boxes containing conductors larger than #4 you need to size the box in accordance with 314.28(A).

Sorry Chris, I know what you mean, but to be clear...

314.28 Pull and Junction Boxes and Conduit Bodies.

(A) Minimum Size. For raceways containing conductors of 4 AWG or larger that are required to be insulated, and for cables containing conductors of 4 AWG or larger, the minimum dimensions of pull or junction boxes installed in a raceway or cable run shall comply with (A)(1) through (A)(3). Where an enclosure dimension is to be calculated based on the diameter of entering raceways, the diameter shall be the metric designator (trade size) expressed in the units of measurement employed.

 

[raider1]

Sorry Chris, I know what you mean, but to be clear...

Your right, I should have said #4 or larger. My bad.

Yes. IF I was using conduit it would be 1-1/4". Since this application is romex installed free inside the framing, I believe I simply pretend I am using 1-1/4" EMT and size accordingly. Is this correct?

Yes, here is what the code says:

When transposing cable size into raceway size in 314.28(A)(1) and (A)(2), the minimum metric designator (trade size) raceway required for the number and size of conductors in the cable shall be used.

Chris