First, if the cable tray is installed outdoors, the protective shield must be installed on the top or every layer. Second, if the installation site is susceptible to mechanical damage or a lot of dust environment, or places with special requirements must be equipped with. Cable tray systems provide a safe, organized, and flexible method for supporting insulated conductors and cables in commercial and industrial electrical installations. These essential components: Example: Stainless steel covers meet NEC 392. For licensed electricians, mastering these principles is essential.