Explore various cable tray types and sizes for electrical installations. Learn about ladder, perforated, solid-bottom, wire mesh, and channel trays in this complete guide. Wire. In practice, cable tray dimensions are a system of interrelated measurements —width, depth, length, and material thickness—that directly affect cable fill compliance, heat dissipation, structural loading, and long-term expandability. 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. Cable tray fill is the proportion of usable cross-sectional area inside a cable tray occupied by installed cables. NEC Article 392 limits fill ratios based on cable type and arrangement — single-layer or stacked — to ensure adequate ventilation, maintain current-carrying capacity, and provide space. association representing the major electrical equipment manufac-turers in the U. International projects are most often made in widths of between 50mm and 900mm and depths of between 50mm and 150mm.