The first method for testing a part's flatness consists of laying the part on a CMM marble with a pre-defined flatness. Then, using a feeler gauge, which is made of strips with already characterized thicknesses, we try to insert strips of different thicknesses under the part. The mechanical and electrical characteristics, tests, certifications, overall quality management, recommendations mentioned in this technical guide only apply to our own cable management ranges and cannot under any circumstances be transposed to si osure, overheating or. 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. From an engineering standpoint, cable tray dimensions are not. 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 industrial applications. Cable tray size calculation. Cable trays vary in size in order to accommodate varying numbers of wires. International projects are most often made in widths of between 50mm and 900mm and depths of between 50mm and 150mm.