Cable trays are a support system for electrical cables, power, signal, and communication and optical fiber cables. NEC section 300-8 does not permit any tube, pipe, or equal for water, air gas, drainage, steam, or any service other than electrical in raceways or cable trays containing. Common types of cable trays include: Side rails connected by transverse rungs. Provide good ventilation and easy cable tie-down. Continuous. ect the minimum bend ra-dius for cables as they exit the bottom of the cable tray. A rung spacing of 6 to 9 inches (150 to 230 mm) is preferable when the cable tray cont d for instrumentation and control applications that require additional protec eferred to support and protect numerous small. An electrical cable tray system serves as a rigid structural raceway designed to support and route electrical cables and wires. Cable trays are permitted for use in. Do we only need to indicate that the cable tray is designed as a support in the drawings, or should there be physical signage upon installation as well? As far as cable tray loads go, I do not yet have all my cables designed (still lacking load information), but will calculate all the cable weights.