EV Charger Cable Sizing Check
Estimate EV charger current, adjusted candidate cable capacity and AC voltage drop for a fixed charging circuit.
Result
Formula
Calculation logicFormula definitions and substituted values.
Estimated charger current (A)
Charger power (kW) * 1000 / (AC supply voltage (V) * Charger power factor * Phase factor)
Charger power (kW) * 1000 / (AC supply voltage (V) * Charger power factor * Phase factor)Adjusted cable capacity (A)
Candidate cable ampacity (A) * Combined cable correction factor
Candidate cable ampacity (A) * Combined cable correction factorCapacity/protection margin (A)
Adjusted cable capacity (A) - max(Estimated charger current (A), Protective-device rating (A))
Adjusted cable capacity (A) - max(Estimated charger current (A), Protective-device rating (A))Estimated voltage drop (V)
Estimated charger current (A) * Voltage-drop path factor * Conductor resistance (Ω/km) * One-way route length (m) / 1000
Estimated charger current (A) * Voltage-drop path factor * Conductor resistance (Ω/km) * One-way route length (m) / 1000Estimated voltage drop (%)
Estimated voltage drop (V) * 100 / AC supply voltage (V)
Estimated voltage drop (V) * 100 / AC supply voltage (V)Voltage-drop margin (%)
Voltage-drop limit (%) - Estimated voltage drop (%)
Voltage-drop limit (%) - Estimated voltage drop (%)Before relying on the result
- Check a single-phase home charger feeder
- Screen a three-phase charger cable against capacity and voltage drop
- Verify charger nameplate data, continuous-load treatment, RCD/RCBO requirements, installation method and current Australian EV requirements before installation.
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