Electrical | Cable Size Calculations

| mm² | Current in conduit (A) | Current in air (A) | |-----|------------------------|--------------------| | 1.5 | 15.5 | 19.5 | | 2.5 | 21 | 27 | | 4 | 28 | 37 | | 6 | 36 | 48 | | 10 | 50 | 66 | | 16 | 68 | 88 |

Common factors:

Load = 24.5 A, ambient 40°C (k₁=0.87), grouping 4 cables (k₂=0.70) [ I_\textmin = \frac24.50.87 \times 0.70 = \frac24.50.609 \approx 40.2 A ] → Choose cable rated ≥40.2 A from tables. Step 3 – Select Cable Size from Current Rating Table Copper, PVC insulated, 30°C ambient (typical IEC table excerpt): electrical cable size calculations

| Factor | Condition | Typical value | |--------|-----------|----------------| | k₁ – Ambient temp | 40°C (IEC) | 0.87 (PVC) | | k₂ – Grouping | 4 cables touching | 0.70 | | k₃ – Thermal insulation | Buried or in insulation | 0.70–0.85 | | k₄ – Altitude (>2000m) | 3000m | ~0.93 | | mm² | Current in conduit (A) |

[ I_\textmin = \fracI_\textloadk_1 \times k_2 \times k_3 \dots ] ambient 40°C (k₁=0.87)

L=80m, I=24.5A, mV/A/m=7.3 [ VD = \frac7.3 \times 24.5 \times 801000 = 14.3 V ] Percentage = (14.3 / 415 = 3.45%) → OK (<5%).