A 22 kW three‑phase EV charger on a 32 A circuit takes 6 mm² copper cable on a typical route. For 20 m of multicore PVC cable enclosed in air at 30 °C, the tool gives 38 A of derated capacity and a voltage drop of 1.04 %.
The case
At 400 V and unity power factor, a 22 kW charger draws 31.75 A in each phase. The circuit is sized for the full 32 A of its curve C breaker. Ze is 0.35 Ω and the voltage drop limit is 5 %. Table 5.1 gives a 2.5 mm² earth, and the earth fault loop impedance is 0.61 Ω.
What changes the answer
Length moves it. Over 60 m, the earth fault loop impedance sets the size, and the tool selects 10 mm² with a drop of 1.85 %.
The charger's circuit also needs its RCD and the spare capacity of the supply checked. The EV charger tool covers both.
See also: Three‑phase EV charger current and EV charger cable size for a 7 kW circuit.