The International Electrotechnical Commission (IEC) provides detailed guidelines for cable tray systems under IEC 61537. This standard outlines the construction requirements, testing methods, and performance parameters for cable trays and related support systems. 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. Establishing partnerships. Cable tray systems provide a safe, organized, and flexible method for supporting insulated conductors and cables in commercial and industrial electrical installations.