Is a cable tray cover plate mandatory?

Whether cable tray or cable ladder requires a cover plate depends on the specific application environment and design requirements. In certain scenarios, such as indoor spaces, tunnels, basements, etc., cable trays and ladders need cover plates to protect wires and cables from damage, prevent hazards like fires or water flooding, and keep them clean by blocking entry of small animals, dust, debris, and other contaminants. However, in other situations—such as outdoor or elevated installations—cover plates may not be necessary, as they could increase wind loads, weight-bearing risks, and complicate maintenance and cleaning efforts. 

Therefore, the decision to install a cover plate should be based on practical conditions, taking into account factors like safety, maintenance, and installation. In summary, the need for a cover plate in cable trays and ladders is determined by the specific application environment and design requirements, requiring consideration of multiple aspects including safety, maintenance, and installation.