Which NEC article covers the wiring methods for duct banks and cable trays in industrial installations?

• A. Article 392 (Cable trays)
• B. Article 310 (Conductors)
• C. Article 215 (Feeders)
• D. Article 110 (General safety)

Answer: (A)

Cable tray systems are specifically governed by NEC Article 392, which lays out the requirements for the use, installation, supports, and fill of cable trays and related raceways in industrial facilities. This article directly addresses how wires and cables are routed within trays, how trays are supported and spaced, allowable loads, and other details essential to safe and reliable tray-based wiring.

The other articles cover different topics: Article 310 focuses on conductors themselves (sizes, ampacity, insulation), Article 215 deals with feeders (larger supply conductors feeding distribution), and Article 110 sets general safety rules. None of these provide the targeted rules for cable trays, which is why Article 392 is the best fit for this question.