Cable tray support quantity can be calculated using a simple formula: Support Quantity = Total Length ÷ Support Spacing + 1 20 ÷ 2 + 1 = 11 supports In a typical project, a 20-meter cable tray with 2-meter spacing requires 11 supports. Cable tray supports are components used to fix and support. 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. Tray Depth is the internal depth of the cable tray in meters (or millimeters). International projects are most often made in widths of between 50mm and 900mm and depths of between 50mm and 150mm. You don't need a PhD—just a consistent method.