Fill Limits: For power cables, the fill must not exceed 40% of the tray's cross-sectional area; for control cables, it's 50%. This calculator features an interactive interface with advanced visualizations. Save your cable tray sizing calculator results as branded PDF. This guide covers the cable tray types and their appropriate applications, the fill rules for each configuration, ampacity derating requirements, separation of power and signal cables, and the decision criteria for choosing cable tray over conduit. These systems, made from metal or plastic, are open structures designed to support electrical conductors, ensuring proper organization and safety.