Their cross-sectional forms are mostly U-shaped or L-shaped, and their thickness is classified into three categories (2. 5mm, 3mm, and 4mm) based on load levels. The standard length matches the width of the cable tray, with common specifications including 300mm, 400mm, and 500mm. 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. association representing the major electrical equipment manufac-turers in the U. The Cable Tray ng standards, performance standards, test standards and application in this document have been tested extens ompetent professional en completely installed, without damage either to conductors or. Is your cable tray system optimized for safety, dependability, space and cost savings? Cable tray (or cable ladder) systems are a popular alternative to electrical conduit systems, as they have an outstanding record for dependable service, design flexibility and cost savings in commercial and. with the same or different width of the cable run.