National Electrical Installation Standards

Standards as High as Your Own

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Monday, April 19, 2021

Question:

Good Day and thank you for this daily Code information.

For a 400-ampere feeder, we have a 4-inch EMT run through the building and have to install a pull box in the run due to the number of bends. How do we size the pull box?

Sammy Daniels

 
A

Answer:

Hi Sammy and thanks for the comments and for the question.

The NEC provides sizing information for pull boxes installed for insulated conductors 4 AWG and larger. Section 314.28 requires for straight pulls, the length of the box or conduit body shall not be less than eight times the metric designator (trade size) of the largest raceway. Where splices or where angle or U pulls are made, the distance between each raceway entry inside the box or conduit body and the opposite wall of the box or conduit body shall not be less than six times the metric designator (trade size) of the largest raceway in the row.

Hope this is helpful.

 

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