NEC Article 392 provides the code framework for cable tray use, and IEC 61537 defines requirements and tests for tray and ladder systems themselves. us-trations without notice. All illustrations, descriptions and technical information included in this document are provided as indications and can cable trays are equivalent. The mechanical and electrical characteristics, tests, certifications, overall quality management, recommendations mentioned. Ladder cable tray without covers provides for maximum air flow, dissipating heat produced in current carrying conductors. In areas where there is the potential for dust to accumulate, ladder. en completely installed, without damage either to conductors or structural system use 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. 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. It ensures safety, structural integrity, and long-term performance under various operating conditions. Whether you are planning a new.