The sum of the cross-sectional areas of all contained conductors at any cross-section of a metal wireway shall not exceed _____.
a) 50%
b) 20%
c) 25%
d) 75%
See answer and applicable Code reference
The correct answer is: b) 20%
Article 376 of the 2011 NEC presents the requirements for installation of metal wireways. As clearly noted in 376.22(A), "The sum of the cross-sectional areas of all contained conductors at any cross section of a wireway shall not exceed 20% of the interior cross-sectional area of the wireway."
