Calculate cable tray fill ratio, weight loading, and derating factors for multi-standard compliance. This calculator features an interactive interface with advanced visualizations. Save your cable tray sizing calculator results as branded PDF. 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. IEC 61537 and IEC 60364 require evaluating tray dimensions based on cable quantity, type, and layout configuration. Follow these simple steps: Define Tray Dimensions: Enter the width and depth of your planned cable tray (in mm or inches). You don't need a PhD—just a consistent method.