All conductors of a circuit, including the neutral and equipment grounding conductors, must be run in the same raceway, cable, trench, cord, or cable tray; except as permitted by 300. Cable tray types, fill rules for single-conductor and multiconductor cables, ampacity derating, separation requirements, and when to use tray vs conduit. When properly selected and installed, cable trays simplify routing, improve accessibility, and support future expansion while. The primary rulebook used in the safe use of cable trays is NEC Article 392. Nor does it apply to the integral parts of electrical equipment [300.
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