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. Each cable tray type performs a different function and comes in various materials such as aluminum, galvanized steel, and FRP. What is Cable Tray? A cable tray is a unit, or set of units. anufactured using a pultrusion process that uses polyester resin or vinyl ester. It provides good corrosion resistance in many corrosive environments. The Ladder Tray features light, rugged, tubular steel construction. Applications: Power plants and substations, Heavy.