They must be used at various key points of the tray system: at the beginning and end of the tray, at corners, T-junctions, and when the tray spans a length greater than 30 meters. Cable ladder systems and cable tray systems shall be manufactured in accordance with BS EN 61537, channel support. Article Summary: A compliant cable tray installation requires a thorough understanding of NEC Article 392, proper structural support, and precise installation techniques. This guide covers the critical steps, from selecting the right electrical cable tray and performing accurate cable fill. 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 the cable tray cont d for instrumentation and control applications that require. Although BS 7671 touches on the subject of cable supports, it does not detail specifically what these support distances should be. 8 (Other Mechanical Stresses (AJ)) in that document provides requirements for cable support.