Attach a Unistrut channel (or trapeze hanger) horizontally between two threaded rods to create a shelf for the tray. You will often need to cut trays to fit specific lengths or corners. 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. Mark the cable tray route based on your electrical cable tray design and site. Another option is to have the factory precut the rods and horizontal supports to the required lengths. Valuable time can be lost starting nuts on rod ends cut improperly. This section will guide you through the necessary steps to ensure a successful. 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.