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. 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. Below are the key principles to guide the layout of E&I cable trays, focusing on practical, safety, and efficiency aspects. Separation of Electrical and Instrumentation Cables Electrical on Top, Instrumentation Below: Typically, electrical trays are positioned above instrumentation trays. A rung spacing of 6 to 9 inches (150 to 230 mm) is preferable when. Article Summary: A compliant cable tray installation requires a thorough understanding of NEC Article 392, proper structural support, and precise installation 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. In order to get it right, installers are supposed to adhere to a plan that ensures that wires are kept cool and the building is stable. The beginning of success is to review the Bill of Quantities (BOQ) so that.