Polyester and Vinyl Ester cable trays are non-metallic, or in a very simple sense, plastic. Fiberglass trays are the least effective at dealing with heat. At 200°F, fiberglass will lose up to 50% of its rated. B manufactures its cable tray in a range of materials with a variety of finishes. Aluminum's exceptional corrosion resistance, particularly. NEC Article 392 outlines the key rules for installing and maintaining industrial cable tray systems. These systems, made from metal or plastic, are open structures designed to support electrical conductors, ensuring proper organization and safety.