Where cable trays support individual conductors and where the conductors pass from one cable tray to another, or from a cable tray to raceway (s) or from a cable tray to equipment where the conductors are terminated, the distance between the cable trays or between the cable tray and the. Where cable trays support individual conductors and where the conductors pass from one cable tray to another, or from a cable tray to raceway (s) or from a cable tray to equipment where the conductors are terminated, the distance between the cable trays or between the cable tray and the. Ladder Cable Trays are a type of cable tray in the shape of a ladder. They are recommended for heavy cable runs as they provide good cable support as well as adequate ventilation. Wire Mesh Cable Trays are mainly used for telecommunication and fiber optic cables. This is a description of how to select, install, and support these metal or plastic frames, on which electrical wires are installed. For licensed electricians, mastering these principles is essential. Cable tray (or cable ladder) systems are a popular alternative to electrical conduit systems, as they have an outstanding record for dependable service, design flexibility and cost savings in commercial and industrial applications. A properly designed and installed cable tray system will provide. NEC Article 392 explains cable trays, their components, appropriate wiring methods for cable trays, and instances where they are and are not permitted for use.