Properly securing cables within the trays is crucial for organization and safety. Horizontal Runs: Cables should be secured at their start, end, and turns, and every 3 to 5 meters along straight horizontal sections. 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. Clause 522-08-04 Where conductors or cables are not supported. This publication is intended as a practical guide for the proper and safe* installation of cable ladder systems, cable tray systems, channel support systems and associated supports. Cable ladder systems and cable tray systems shall be manufactured in accordance with BS EN 61537, channel support. 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. Fittings can, on the one hand, be used for horizontal or vertical changing of the routing direction or, on the other, to change the height or width of the. The National Electrical Code (NEC) is the ultimate authority for any cable tray installation.