This guide covers the critical steps, from selecting the right electrical cable tray and performing accurate cable fill calculations to managing a safe cable pull through and ensuring all bonding and grounding requirements are met. Article Summary: A compliant cable tray installation requires a thorough understanding of NEC Article 392, proper structural support, and precise installation techniques. The most common method of installing power cables in tunnels is mounting them on metal brackets or cable trays attached to the sides. Cable. Installation of Cable in Cable Trays involves precise routing on support systems, NEC/IEC compliance, grounding, ampacity derating, bend radius control, segregation of services, fire safety, labeling, and reliable cable management for industrial and commercial facilities.