The thickness of the tray depends on how frequently it is supported. 5 mm or above is typically recommended for longer spans. 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. This article explains the key considerations to help you make the right choice. The thickness and width of a cable tray directly impact its load-bearing. Choosing the appropriate size and dimensions for a cable tray is critical for performance, maintenance, and potential future improvements.