EV charger load equation
This calculator estimates charger current and total planned feeder load after applying charger quantity and simultaneity.
Icharger = P × 1000 / (V × PF)Icharger = P × 1000 / (√3 × V × PF)Iplanned = Icharger × N × Kswhere:
- Icharger
- Current per chargerA
- P
- Power per chargerkW
- V
- Supply voltageV
- PF
- Charger power factor
- N
- Number of chargers
- Ks
- Simultaneity factor as a decimal
- Iplanned
- Planned distribution load currentA
Final EV charging design should also check load management, earthing system, RCD/RCBO type, SPD selection, and local EV charging rules.
Assumptions
- AC chargers
- Balanced three-phase loading when three-phase is selected
- Demand management is represented by simultaneity factor
Important Warnings
- Final EV charging design must check IEC 61851, local code, RCD/RCBO requirements, earthing system, and load management.
- DC fast chargers require a more detailed system study.
FAQ
What is simultaneity factor?
It estimates how much of the installed charging power is used at the same time. Use project-specific demand management data when available.
Does this choose RCD or RCBO type?
No. EV charging residual-current protection depends on charger design, DC leakage handling, local rules, and manufacturer instructions.