Conductor Circular Mil Area & Pulling Eye Tensile LimitEngineering Cross-Section Area
Cross-sectional conductor area (kcmil / AWG / mm2). Governs maximum safe mechanical pulling force without elongating or necking the metal core. Safe threshold standard: 0.008 lb per circular mil (70 N/mm2) for annealed copper; 0.006 lb per circular mil (42 N/mm2) for AA-8000 aluminum.
Default: 500 kcmil (500,000 cmil)
Weight Correction Factor (w_c)Conductor Geometry Multiplier
Dimensionless coefficient accounting for mutual wedging and lateral pinching between multiple conductors in a circular raceway. Equals 1.0 for single cables; calculated dynamically for 3 conductors in cradle configuration as 1 + (4/3)*(d/(D-d))^2, or triangular configuration as 1 / sqrt(1 - (d/(D-d))^2).
Default: 1.18 to 1.35
Sidewall Bearing Pressure (SWBP / SP)Radial Force Per Linear Bend Length
Radial crushing force exerted on the cable insulation and jacket against the inner raceway curve during tensioned bends. Calculated as T_out / R (single cable) or T_out*(3*w_c - 2)/(3*R) (three cables). IEEE 525 safe benchmark limits: 500 lbs/ft (7.3 kN/m) for standard 600V power cables, 1,000 lbs/ft (14.6 kN/m) for shielded MV/HV cables, and 300 lbs/ft (4.4 kN/m) for fiber optic cables.
Default: Max 500 lbs/ft
Cable Jamming Ratio (D / d)Clearance Dimension Ratio
Ratio of conduit inside diameter (D) to single cable outside diameter (d). When pulling 3 cables, if D/d falls between 2.8 and 3.2, cables can slip from a triangular into a flat side-by-side alignment in bends, wedging solidly against raceway walls and causing catastrophic lockup.
Default: Outside 2.8 - 3.2
Dynamic Coefficient of Friction (mu)Surface Interface Friction Factor
Kinetic friction multiplier between the cable jacket (PVC, XLPE, HDPE) and raceway wall (EMT, RMC, PVC). Benchmarks: 0.15 to 0.20 for high-grade synthetic polymer pulling lubricant; 0.35 for standard soap/wax lube; 0.50 or higher for unlubricated dry pulls.
Default: 0.20 (Lubricated)
NEC Conduit Fill PercentageRaceway Space Capacity Ratio
Ratio of total conductor cross-sectional area to internal raceway area. Regulated under National Electrical Code (NEC) Chapter 9, Table 1: maximum 53% for 1 conductor, 31% for 2 conductors, and 40% for 3 or more conductors.
Default: Max 40.0%
