Where run vertically, nonmetallic wireways shall be securely supported at intervals not exceeding _____ ft, unless listed otherwise, with no more than one joint between supports.
See answer and applicable Code reference
The correct answer is: a) 4
Article 378 covers the use, installation, and construction specifications for nonmetallic wireways and associated fittings. As noted in Sec. 378.30(B), "Vertical runs of nonmetallic wireway shall be securely supported at intervals not exceeding 4 ft, unless listed for other support intervals, and shall not have more than one joint between supports."