ISO 6469-4:2015

Overview

ISO 6469-4:2015 - Electrically propelled road vehicles - Safety specifications - Part 4: Post crash electrical safety - defines electrical safety requirements for electrically propelled road vehicles after a crash. It focuses on protection of persons inside and outside the vehicle by specifying post‑crash limits and tests for voltage class B electric circuits (>(30 V and ≤1 000 V) a.c. or >(60 V and ≤1 500 V) d.c.). The standard applies to full electric and hybrid road vehicles (excludes motorcycles and mopeds), but it does not prescribe crash test procedures - it is applied in accordance with published regional crash test protocols. It also clarifies that it is not a comprehensive manual for first responders or repair personnel.

Key Topics and Requirements

• Post‑crash electrical safety criteria: After a crash, at least one protection criterion must be met for each voltage class B circuit (voltage limit, isolation resistance, physical protection, or electrical energy limit).
• Voltage limit: Voltage must be ≤30 V a.c. (rms) or ≤60 V d.c. at a defined time point after impact (either 10 s after initial impact if vehicle stops within 5 s, or 5 s after the vehicle comes to rest).
• Isolation resistance: Minimum isolation resistance values are specified per voltage class and circuit type:
  • Separated a.c. and d.c.: 500 Ω/V for a.c., 100 Ω/V for d.c.
  • Combined circuits: multiple compliance options (e.g., 500 Ω/V overall or 100 Ω/V plus additional protections).
• Physical protection (IPXXB): Protection against direct contact with live parts using enclosure/barrier requirements per ISO 20653; includes potential equalisation and low resistance bonding paths.
• Electrical energy limits & capacitors: Limits on stored energy (including Y‑ and X‑capacitors) to reduce shock risk; special attention to potential body currents from Y‑capacitors.
• RESS electrolyte spillage: Requirements and test procedures addressing battery electrolyte leakage post‑crash.
• Testing guidance: Test setup, conditions and procedures are detailed for verifying voltage limit, isolation resistance, physical protection and energy limits.

Applications and Users

ISO 6469-4:2015 is used by:

• Automotive OEMs and design engineers for post‑crash electrical safety design and validation.
• Safety and compliance teams during vehicle homologation and certification.
• Test laboratories performing electrical safety verification following regional crash tests.
• Regulators and standardization bodies integrating post‑crash electrical criteria into vehicle safety regulations.

Note: emergency services should consult dedicated responder guidance - this standard is not a substitute for first‑responder protocols.

Related Standards

• ISO 6469‑1: On‑board rechargeable energy storage system (RESS)
• ISO 6469‑2: Vehicle operational safety means and protection against failures
• ISO 6469‑3: Protection of persons against electric shock
• ISO 20653: Degrees of protection (IP code) for road vehicle electrical equipment
• ISO/TR 8713: Vocabulary for electrically propelled road vehicles

Keywords: ISO 6469-4:2015, post crash electrical safety, electrically propelled road vehicles, voltage class B, isolation resistance, IPXXB, RESS electrolyte spillage, electric shock protection.