Commonly called the Load Class, this defines the load-carrying capability of the tray for a specific support span distance. The design and cost of the cable tray is greatly affected by this designation. Each cable tray type performs a different function and comes in various materials such as aluminum. The following are popular cable tray types. Cable trays are used as an alternative to open wiring or electrical conduit systems, and are commonly used for cable management in. Cable tray systems are engineered support structures designed to route, support, and protect insulated electrical cables used for power distribution, control, instrumentation, and communication. Unlike conduit systems, cable trays allow cables to be laid in bundles, improving accessibility, heat.