Medium Voltage Cable Sizing Calculator -

At 1.5m (deeper = hotter), factor: 0.96.

Three conductors touching (trefoil) traps heat. Correction: 0.90. medium voltage cable sizing calculator

Fault current = 15 kA for 0.5 seconds. Minimum copper area: ( A = \frac{I_{sc} \times \sqrt{t}}{k} ) (k for XLPE copper = 143) ( A = \frac{15,000 \times \sqrt{0.5}}{143} \approx \frac{15,000 \times 0.707}{143} \approx \frac{10,605}{143} \approx 74 , mm^2 ) 1/0 AWG is ~53.5 mm² → Fails short-circuit withstand! Fault current = 15 kA for 0

Mark: “So we need a cable with base rating of 201A / 0.664 = 303A minimum.” Length: 15,840 ft

Mark asks, “Why not just use an online calculator?”

( V_{drop} = \sqrt{3} \times I \times (R \cos\theta + X \sin\theta) \times L ) For 1/0 AWG copper: R=0.124 Ω/1000ft, X=0.048 Ω/1000ft, power factor 0.85. Length: 15,840 ft. ( V_{drop} \approx 1.73 \times 201 \times (0.124×0.85 + 0.048×0.53) \times 15.84 ) ( \approx 347 \times (0.1054 + 0.0254) \times 15.84 ) ( \approx 347 \times 0.1308 \times 15.84 \approx 719 ) volts.