National Electrical Installation Standards

Standards as High as Your Own

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Wednesday, December 29, 2021

Question:

Greetings CQD,

When sizing a pull box for 600 kcmil conductors in a feeder circuit installed in a 4-inch rigid metal conduit, what is the minimum size required. The pull box will be installed such that it is an angel pull (90 degree) as compared to a straight pull. Any assistance would be greatly appreciated.

Jesus Garcia

A

Answer:

Hello Jesus,

According to Section 314.28(A)(2) 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 a row. This distance shall be increased for additional entries by the amount of the sum of the diameters of all other raceway entries in the same row on the same wall of the box. Each row shall be calculated individually, and the single row that provides the maximum distance shall be used. Since your conduit is 4-inch, the minimum distance between conduit entries in the pull box must not be less than 24 inches (six times the size of the raceway enclosing the same conductors). 

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