Learn how to install cable trays for large-scale projects with our professional, step-by-step guide covering industry standards, safety protocols, and efficient routing techniques. But before you lay the first tray or clamp down a single cable, you need a solid plan. This guide breaks down the process step by step. The Cable Tray system is installed in electrical rooms, plant rooms, and service corridors. When installed and engineered properly, cable. Article Summary: A compliant cable tray installation requires a thorough understanding of NEC Article 392, proper structural support, and precise installation techniques.