The Cable Tray Sizing Calculator is an electrical calculator tool designed to determine the correct cable tray dimensions for electrical installations. Accurate fill ratio analysis and tray sizing per NEC, IEC 60364, and BS 7671 standards. Select Fill Standard: Choose 40% for power cables (NEC compliant) or 50% for. Calculate cable tray fill ratio, weight loading, and derating factors for multi-standard compliance. Save your cable tray sizing calculator results as branded PDF. Size cable trays per NEC 392 based on cable count, diameter, tray type, and future expansion needs. Enter your cable schedule below to get started. The calculator computes the cross-sectional area of all.