Short Circuit Calculation For Cable Sizing [2021] May 2026

The minimum CSA is 37.5 mm². The nearest standard cable is 50 mm² (since 35 mm² is below 37.5, it fails).

The fundamental equation (derived from Joule’s law and specific heat capacity) is: short circuit calculation for cable sizing

Example: ( I_sc = 15 kA, t = 100 ms ) ( S = (15 \times 10) / 4.52 = 150 / 4.52 \approx 33.2 , mm^2 ) → use 35 mm². The minimum CSA is 37

[ k \cdot S \ge I_sc \cdot \sqrtt ]