Cable trays installed in dusty environments. The fixing points are as follows: When laid horizontally, at both ends of the cable, at bends, and. 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. Cable tray installation must comply with specific technical standards to ensure electrical safety, system reliability, and long-term maintainability. Route. This method statement covers the site installation of the cable tray & ladders and the requirements of checks to be carried out. 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.