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Monday, August 9, 2021

Question:

Great forum and please keep up the good work! Chapter 9, Table 1, Note 4 allows a 60% fill for when conduit/tubing is used as nipple and does not exceed 24". Is there any wording similar to that concept of a nipple for a wireway or trough? We have a situation where we would like to use a section of wireway as a chase through an exterior wall that is less then 24" but the fill would be more that the 20% cross sectional allowed under 367.22 (A). Any guidance would be greatly appreciated.

Douglas Begg

A

Answer:

Hi Douglas,

The requirements for conduit nipples in lengths 24 inches and shorter do not apply to metal wireways. The 20% fill requirement for a metal wireway must generally not be be exceeded. The limit of 30 current carrying conductors in a wireway could be exceeded, but at that point all correction factors and ampacity adjustment factors should be applied. See 376.22(A) and (B).

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