Junction box sizing

[George Stolz]

314.28.

A junction box has a 3" straight pull left to right, and a 2" angle pull from left to bottom.

How tall does the box have to be? I think 15", the answer key says 12".

 

[Ponchik]

I think the answer key is incorrect.

12" is distance between the conduit not the size of the box.

Minimum size of the box is 15" by 24"

 

[infinity]

I think the answer key is incorrect.

12" is distance between the conduit not the size of the box.

Minimum size of the box is 15" by 24"

The box is 24" long so the distance between the two angle pull conduits could be at least 20", so how did you calculate to get 15"?

 

[George Stolz]

2" x 6 = 12 between the angle pull raceways.

(2" x 6) + 3" = 15" for the height of the box.

The 2" and 3" enclose different conductors.

 

[Dennis Alwon]

I would tend to agree with the book since the straight pull really has no affect on the height. The problem as I see it is whether that straight pull should come into play with the angle pull and IMO it should not but by the wording in the NEC it appears to come in-- I am not sure that is the intent.

 

[Dennis Alwon]

I will add this graphic but I am not sure if you are using Mike Holt books or not

 

[Ponchik]

The box is 24" long so the distance between the two angle pull conduits could be at least 20", so how did you calculate to get 15"?

Could be at least 20" or Has to be at least 20". Are you thinking what the premade boxes are sized to?

 

[infinity]

2" x 6 = 12 between the angle pull raceways.

(2" x 6) + 3" = 15" for the height of the box.

The 2" and 3" enclose different conductors.

This is the part I'm missing. The box is already 24" long (straight pull) so couldn't the angle pull conduits already be separated by at least 20"?

 

[George Stolz]

I will add this graphic but I am not sure if you are using Mike Holt books or not

Dennis - that's the idea, and where my thinking went sideways. The box would have to be 15" wide for the angle pull, but only 12" tall. Mental flatulence.

 

[Little Bill]

Mental flatulence.

Had to read that a few times!

BF!:lol: