When vertically installed, the height of cable trays from the ground should not be lower than 1. If the above standards cannot be met, metal covers must be added for protection. This spacing is crucial for adequate maintenance access, ease of inspection, and ensuring proper airflow for effective heat dissipation. This does not apply. 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. The NEC has a requirement for ladder-type cable trays. The mechanical and electrical characteristics, tests, certifications, overall quality management, recommendations mentioned.