Select your tray type (ladder, ventilated trough, solid bottom, or channel), enter the tray width and usable depth, then add cables by size and quantity. The calculator computes the total cable cross-sectional area and compares it against the applicable NEC fill limit. Select Fill Standard: Choose 40% for power cables (NEC compliant) or 50% for. Calculate the appropriate cable tray size based on your cables and fill requirements.