Medium Voltage Cable Sizing Calculator 〈Updated〉

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

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

Elena stops him. “You forgot the derates.” A true MV calculator doesn’t just do Ohm’s law. It applies six correction factors sequentially. Mark asks, “Why not just use an online calculator

(ignored for continuous max case—safety first). factor: 0.96. Per ICEA P-32-382

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

Per ICEA P-32-382, for 90°C cable in 35°C soil (base rating is 25°C soil): ( k_{temp} = \sqrt{\frac{90 - 35}{90 - 25}} = \sqrt{\frac{55}{65}} = \sqrt{0.846} \approx 0.92 ) Result: The cable can only carry 92% of its base rating.