The formula used to calculate cable tray capacity is: Cable Tray Capacity = (Tray Width × Tray Depth × Fill Ratio) / Cable Cross-sectional Area Where: Tray Width is the internal width of the cable tray in meters (or millimeters). Our free calculator helps you determine the correct tray size based on NEC and IEC standards. Follow these simple steps: Define Tray Dimensions: Enter the width and depth of your planned cable tray (in mm or inches). You need to install 50 power cables, each with a diameter of 0. IEC 61537 covers cable tray and cable ladder systems for the support and accommodation of cables, while NEC Article 392 governs cable. A Cable Tray Capacity Calculator is an essential tool for electrical engineers, contractors, and project managers involved in the installation and management of electrical cables.