Codes, Standards, and General Requirements Cable tray systems are recognized as a wiring method by many national and international electrical codes. When properly selected and installed, cable trays simplify routing, improve accessibility, and support future expansion while. en completely installed, without damage either to conductors or structural system use maintain spacing or to keep cables in place when the tray is ect the minimum bend ra-dius for cables as they exit the bottom of the cable tray. A rung spacing of 6 to 9 inches (150 to 230 mm) is preferable when. Is your cable tray system optimized for safety, dependability, space and cost savings? Cable tray (or cable ladder) systems are a popular alternative to electrical conduit systems, as they have an outstanding record for dependable service, design flexibility and cost savings in commercial and. us-trations without notice. All illustrations, descriptions and technical information included in this document are provided as indications and can cable trays are equivalent. The mechanical and electrical characteristics, tests, certifications, overall quality management, recommendations mentioned. Cable tray types, fill rules for single-conductor and multiconductor cables, ampacity derating, separation requirements, and when to use tray vs conduit. Vertical distance between adjacent cable trays, measured from the bottom of upper tray to the bottom of the lower tray, shall be at least 400 mm.