[ k \cdot S \ge I_sc \cdot \sqrtt ]
Disclaimer: This report is for educational purposes. Actual design must comply with local regulations (NEC, IEC, BS 7671) and be verified by a licensed professional engineer. short circuit calculation for cable sizing
The fundamental equation (derived from Joule’s law and specific heat capacity) is: [ k \cdot S \ge I_sc \cdot \sqrtt
The minimum CSA is 37.5 mm². The nearest standard cable is 50 mm² (since 35 mm² is below 37.5, it fails). mm^2 ) → use 35 mm².
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.
