Junction Box Size

[NEC User]

Are my calculating the minimum size required correctly per NEC 314.28(2)?

I have a pullbox with a 4 inch conduit entering and a 4" conduit exiting at the opposite wall (straight line). There is also a 1 inch conduit entering the bottom. So the 1" conduit is perpendicular to the 4" conduits. There is a splice within the box.

The length needs to be 6x4"=24"
The width needs to be 6X1"=6"
The depth doesn't have any requirement

Hoffman a reputable manufacturer has a standard size of 24"x6"x4.5" however I don't think a 4.5" depth is suitable given a 4" conduit is being used.

So I'm going to specify the minimum box size required is 24"x6"x6" which will need to be custom made.

 

[jusme123]

http://ecmweb.com/code-basics/sizing-junction-boxes

 

[augie47]

As will note in justme's reference and from 314.28, straight pulls require a 8X multiplier.
What you describe seems to fit a wireway application better than j box.
Does you 1" enter opposite a removable cover or do I misunderstand ?

 

[NEC User]

I basically need to replace the existing junction box in the attachment and specify the size. I wasn't at this site visit and I don't think the box had a removable cover.

 

[petersonra]

I basically need to replace the existing junction box in the attachment and specify the size. I wasn't at this site visit and I don't think the box had a removable cover.

what's wrong with the old one? a little paint and it will fix up nicely.

 

[infinity]

Are my calculating the minimum size required correctly per NEC 314.28(2)?

I have a pullbox with a 4 inch conduit entering and a 4" conduit exiting at the opposite wall (straight line). There is also a 1 inch conduit entering the bottom. So the 1" conduit is perpendicular to the 4" conduits. There is a splice within the box.

The length needs to be 6x4"=24"
The width needs to be 6X1"=6"
The depth doesn't have any requirement

Hoffman a reputable manufacturer has a standard size of 24"x6"x4.5" however I don't think a 4.5" depth is suitable given a 4" conduit is being used.

So I'm going to specify the minimum box size required is 24"x6"x6" which will need to be custom made.

Straight pulls require 8X not 6X. The depth needs to be enough to get the locknuts and bushings on. For a 4" conduit 6" would be my minimum size.

 

[Dennis Alwon]

Here is a diagram