When installing two cable trays in parallel at the same height, the distance between them should be no less than 0. This spacing is crucial for adequate maintenance access, ease of inspection, and ensuring proper airflow for effective heat dissipation. It ensures that cables are properly supported and protected, reduces the risk of cable damage, and facilitates maintenance and management. Proper installation is not just about placing the. The spacing between trays, whether horizontal or vertical, depends on various factors like cable type, environment, and tray material. Select the Tray Type: Choose a perforated cable tray that meets the NEC specifications for your application. When offloading tray from a flat deck trailer using an overhead crane, care should be exercised in the placement and length of the slings to prevent crushing the product (siderails).