CableSpec Pro

📐 Standards Basis & Assumptions

CableSpec Pro uses simplified ampacity tables and formulas derived from:

• IEC 60364-5-52 (Table B.52.2–B.52.5): Base current-carrying capacities for various installation methods, insulation types, and conductor materials.
• IEEE Std 835: Ampacity tables for power cables. Used as cross-reference for copper/aluminum conductors in air and direct-buried configurations.
• IEC 60364-5-54 (Clause 543.1): Adiabatic equation for short-circuit withstand: S = I√t / k, where k depends on conductor and insulation material.

Derating factors applied:

• Temperature derating (Ct): Based on IEC 60364-5-52 Table B.52.14/15. Formula: Ct = √((Tmax − Tambient) / (Tmax − Tref))
• Grouping derating (Cg): Based on IEC 60364-5-52 Table B.52.17. Interpolated lookup for number of grouped circuits.
• Soil resistivity derating (Cs): For buried cables, based on IEC 60364-5-52 Table B.52.16. Applied only for methods D1/D2.

Voltage drop: Calculated using mV/A/m values derived from conductor resistance and reactance at 50 Hz. Formula accounts for power factor and phase configuration.

Simplifying assumptions: Tabulated ampacities are representative mid-range values. Actual project conditions (cable manufacturer data, exact laying arrangement, harmonic content, altitude, etc.) may require adjustment.