Top Clearance: The top of the cable tray should maintain a minimum distance of 0. 3 meters from the ceiling or any other obstructions. The following pages address the 2014 National Electrical Code® requirements for cable tray systems as well as design solutions from practical experience. This spacing is crucial for adequate maintenance access, ease of inspection, and ensuring proper airflow for effective heat dissipation. It also helps reduce the risk of. The NEC requires that cable trays must be supported by members at an interval specified by the cable tray manufacturer, but not more than 5 feet for horizontal runs to support the weight of the cables and other loads. During forklift offloading on uneven ground, one must exercise extreme caution to prevent load shifting.