Charging Modes 2, 3, and 4
Charging modes 2, 3, and 4 are IEC classifications for how an electric vehicle connects to its electricity supply and where control and protection functions are located. They describe charging arrangements, not connector shapes, charging-network products, or the similarly named North American charging levels. IEC 61851-1:2017 — General requirements for conductive charging systems
How the modes differ
- Mode 2 supplies AC from a standard socket through a cable that includes an in-cable control and protection device. The portable unit provides control-pilot and safety functions that a plain household cable does not.
- Mode 3 supplies AC through dedicated, permanently connected EVSE. The station communicates the available current to the vehicle and controls when the supply is energized. A Mode 3 station can use a tethered cable or a socket for a detachable cable.
- Mode 4 supplies DC from an off-board charger. The charging equipment converts grid AC to controlled DC and coordinates voltage and current with the vehicle before and during energy transfer. Dedicated requirements for DC charging equipment are covered by IEC 61851-23. IEC 61851-23:2023 — DC electric vehicle supply equipment
Mode does not determine the power by itself. Available charging power also depends on the electrical installation, EVSE, cable and connector ratings, voltage, phase configuration, vehicle inlet, battery voltage, thermal conditions, and the vehicle's onboard or DC charging limit.
Mode 2 is often used for portable or occasional AC charging, while Mode 3 is the normal arrangement for dedicated home and public AC charging. Mode 4 covers public and private DC charging from low-power equipment through high-power fast chargers. For the wider electrical path and the practical factors that limit power, see EV Charging: The Complete System.