ISO 17409:2020

Overview

ISO 17409:2020 - Electrically propelled road vehicles - Conductive power transfer - Safety requirements - defines electric safety requirements for conductive connection of electrically propelled road vehicles (EVs) to external electric circuits (external power supplies and loads). The standard covers on‑board sections of vehicle power supply circuits and control functions used for the vehicle↔external circuit connection. It applies to charging modes 2, 3 and 4 as defined in IEC 61851‑1, includes requirements for conductive DC and AC power transfer, and adds rules for reverse power transfer (V2G). Mode 1 is intentionally excluded. Note: the document is focused on vehicle-side safety and does not replace workplace safety procedures for manufacturing, maintenance or repair.

Key technical topics and requirements

ISO 17409:2020 addresses vehicle-side safety topics central to conductive EV charging and discharge:

• Vehicle inlet, plug and cable requirements for safe mating and separation during charging.
• Protection against electric shock: basic protection when connected, protective conductor requirements, isolation resistance for AC and DC connections, and rules for unmated vehicle contacts.
• Insulation coordination and touch current limits; compatibility with residual current devices (RCD).
• Thermal protection and overcurrent requirements**: overload and short‑circuit protection for AC and DC, arc protection for DC connections, and residual energy after disconnection.
• AC-specific requirements: voltage/frequency ranges, current characteristics, inrush current, interlock functions and phase order.
• DC-specific requirements: disconnection devices, control pilot functions, isolation resistance monitoring, connector locking, contact temperature and protection against load-dump overvoltage.
• Reverse power transfer (AC/DC): output power quality, prevention of disconnection under load, protections against electric shock and thermal incidents, and battery overdischarge safeguards.
• Operational, marking and owner’s manual requirements, plus test procedures (protective conductor resistance, isolation resistance, withstand voltage, inrush/touch current, DC contact temperature, etc.).

Practical applications - who uses this standard

ISO 17409:2020 is essential for:

• EV manufacturers designing on‑board charging and power interfaces
• Charging-station and EVSE designers ensuring vehicle compatibility and safety for conductive connections
• Component suppliers (inlets, plugs, cables, connectors, control pilot systems)
• Test labs and certification bodies carrying out compliance tests and type approval
• Fleet operators and integrators implementing V2G and bidirectional systems
• Regulators and safety engineers writing procurement/specification documents

Using ISO 17409 helps ensure safe conductive charging/discharging, minimizes electrical shock and thermal risks, and supports interoperable vehicle↔infrastructure solutions.

Related standards

• IEC 61851‑1 (charging modes definitions and EVSE requirements)
• IEC 61851‑23 (isolated DC EV charging station requirements)
• ISO 6469‑3 (general electrical safety for electrically propelled vehicles)

Keywords: ISO 17409:2020, conductive power transfer, EV charging safety, charging modes 2 3 4, reverse power transfer, AC/DC charging, vehicle inlet, isolation resistance, touch current, RCD, V2G.