ISO 5474-2:2024

Overview

ISO 5474-2:2024 - Electrically propelled road vehicles - Part 2: AC power transfer - specifies functional and safety requirements for conductive alternating-current (AC) power transfer between electrically propelled road vehicles and external electric circuits. Together with ISO 5474-1, it applies to vehicle power supply circuits for AC voltages up to 1 000 V a.c. and covers conductive charging modes 2 and 3 (IEC 61851-1) as well as reverse power transfer (vehicle-to-grid, vehicle-to-home, vehicle-to-load scenarios). The standard focuses on the vehicle side; external electric circuits are out of scope.

Key topics and technical requirements

• Scope & applicability: Conductive AC charging up to 1 000 V, vehicle power supply circuits, examples of on-board charger configurations (Annex A).
• Safety requirements: Protection against electric shock (insulation resistance, touch current, insulation coordination), protective conductor requirements, and basic protection for unmated vehicle contacts.
• Thermal protection: Requirements for normal operation, overcurrent protection, residual energy after disconnection, and arc protection.
• Functional parameters: Voltage and frequency ranges, inrush current, continuous load current, power factor, phase order and three-phase operation considerations.
• Reverse power transfer: Functional and safety rules for grid-forming and grid-following modes, including unearthed and earthed external circuits (vehicle-to-load, vehicle-to-grid, vehicle-to-home).
• Hardware interfaces: Requirements for EV plugs, vehicle inlets, on-board standard socket-outlets, and cable/plug compatibility per IEC 62196 series.
• Electromagnetic compatibility (EMC) and protection against unintended power transfer.
• Testing & verification: Test procedures such as protective conductor resistance, insulation resistance, withstand voltage, touch current, and inrush current measurements.
• Documentation: Owner’s manual and marking requirements.

Applications and who uses it

ISO 5474-2:2024 is used by:

• Automotive OEMs and EV powertrain engineers designing on-board chargers and vehicle power supply circuits.
• EV charger and connector manufacturers implementing compliant EV plugs, vehicle inlets and socket-outlets.
• Test laboratories and certification bodies performing safety, EMC and functional testing (insulation, touch current, inrush).
• Grid operators, energy service providers and integrators deploying V2G/V2H solutions and assessing reverse power transfer safety.
• Regulators and standards committees aligning national safety and installation rules for AC charging.

Practical benefits include clearer requirements for safe conductive AC charging, standardized reverse power transfer behavior, and harmonized test methods to support market access and interoperability.

Related standards

• ISO 5474-1:2024 (General requirements for conductive power transfer)
• ISO 6469-3 (Electrical safety for EVs)
• IEC 61851-1 (EV conductive charging - modes)
• IEC 62196-1 / IEC 62196-2 (Plugs, inlets and connectors)
• IEC 60664-1, IEC 60038 and related IEC low-voltage/installation standards

Keywords: ISO 5474-2:2024, AC power transfer, conductive charging, reverse power transfer, vehicle-to-grid, vehicle-to-home, EV plug, vehicle inlet, IEC 61851, IEC 62196.