The calculation sums the cross-sectional areas of all cables including their outer sheaths and checks against the maximum fill area for the selected tray type. IEC 61537 covers cable tray and cable ladder systems for the support and accommodation of cables, while NEC Article 392 governs cable. Calculate cable tray fill ratio, weight loading, and derating factors for multi-standard compliance. This calculator features an interactive interface with advanced visualizations. This is a description of how to select, install, and support these metal or plastic frames, on which electrical wires are installed. Follow these simple steps: Define Tray Dimensions: Enter the width and depth of your planned cable tray (in mm or inches). The fill rules differ significantly between single-conductor cables and multiconductor cables, and between ladder tray and solid-bottom tray.