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). A practical NEC Article 392 cable tray design guide — tray types, fill calculations for single conductors vs. multiconductor cable, support spacing, grounding/bonding as an equipment grounding conductor, and power/low-voltage separation. 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). The worked example walks through a mixed power + control cable run step by step — adapt the same method to your next project.
