[ S = \frac\sqrt50,000^2 \times 0.1115 = \frac\sqrt250 \times 10^6115 = \frac15,811115 \approx 137.5 \ \textmm^2 ]
[ S = \frac\sqrtI^2 \times tk ]
| Phase Conductor (mm²) | Minimum Earth Cable (mm²) | |-----------------------|----------------------------| | ≤ 16 | Same as phase | | 25 – 35 | 16 | | 50 – 95 | 25 | | 120 – 150 | 35 | | 185 – 240 | 50 | | ≥ 300 | 70 (or 50% of phase area) | Note: For small circuits (≤ 16 mm²), the earth is equal to the live conductor. System: 400V, 50kA prospective earth fault current, 0.1s disconnection time (via MCCB), copper conductor with PVC insulation.
150 mm² copper.
90%/109)
