Ladder cable tray without covers provides for maximum air flow, dissipating heat produced in current carrying conductors. Dust buildup is minimal compared to other types of cable tray, such as ventilated trough or solid bottom. maintain spacing or to keep cables in place when the tray is 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. us-trations without notice. All illustrations, descriptions and technical information included in this document are provided as indications and can cable trays are equivalent. Fittings can, on the one hand, be used for horizontal or vertical changing of the routing direction or, on the other, to change the height or width of the. The main components of a cable tray system include tray sections, fittings, supports, and accessories. A typical cable tray. Hubbell's NEXTFRAME® Ladder Tray is the effective and widely used cable runway that supports and delivers bundles of cable between cabinets, racks, and closets, along walls, and suspended from ceilings. The Ladder Tray features light, rugged, tubular steel construction.