The NEC rule requires that the cable cross-sectional areas together may not exceed 50% of the tray area (width x depth = fill). Cables will nearly completely fill the cable tray when reaching the 50% cable fill, due to empty space between the surface of the. A 12 in ladder tray loaded to 4 in depth has 48 sq in of tray area; with 24 #12 THHN conductors at 0. 0133 sq in each, the screen is about 0. IEC 61537 covers cable tray and cable ladder systems for the support and accommodation of cables, while NEC Article 392 governs cable. Properly sizing your cable tray is critical for safety and compliance. 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). Select Fill. Cable tray is the preferred wiring method for industrial facilities, data centers, and large commercial buildings where routing dozens or hundreds of cables through individual conduits would be impractical and expensive. Choose units tray type and allowed fill limit. Get total cable area fill percentage remaining capacity and a pass fail indicator plus downloads.
