The standard NEMA lengths for cable tray are 12, 20, 24 and 30-feet, although some manufacturers like Eaton offer cable tray in lengths up to 40 feet. Selecting a cable tray length is based on several criteria, including: The required load that the cable tray . 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. 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. 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 the cable tray cont d for instrumentation and control applications that require. The majority of the sections have a length of 3 meters, as this is easy to transport and can be compactly placed on the shipping trucks. The width required will be determined by the number of cables to be laid side-by-side. Small trays (50mm) are utilized in a small number of data lines, whereas. The exception is that 9 inches is the maximum allowable rung spacing for a ladder cable tray supporting any 1/0 through 4/0 single conductor cables [See Section 392. Standard Aluminum Ladder • The rungs provide a convenient anchor for tying down cables in vertical runs or where the. The depth dimension of cable trays, also referred to as height or rail height, measures the vertical distance from the tray bottom to the top of the side rails. Common electrical cable tray dimensions for depth include 25mm, 50mm, 75mm, 100mm, and 150mm in metric specifications, with equivalent.