[ I_b = \frac30000\sqrt3 \cdot 400 \cdot 0.85 \cdot 0.9 \approx 56.6 \text A ]
Short-circuit check: [ S_min = \frac\sqrt(5000)^2 \cdot 0.1143 \approx \frac1581143 \approx 11.1 \text mm^2 ] Selected 16 mm² > 11.1 mm² → OK. how to size cable
Correction factors: k_t=1, k_g=1 → (I_t \ge 56.6) A. [ I_b = \frac30000\sqrt3 \cdot 400 \cdot 0