ISO 10924-1:2016

Overview - ISO 10924-1:2016 (Road vehicles - Circuit breakers)

ISO 10924-1:2016 defines terms and sets general test requirements for circuit breakers used in road vehicles with nominal voltages of 12 V d.c., 24 V d.c., 48 V d.c. and 450 V d.c. This part is the foundational document of the ISO 10924 series and is intended to be used together with the other parts (user’s guide and device-specific requirements). It covers definitions, marking, general performance criteria and the test program applicable to automotive circuit breakers (excluding circuit breaker holders such as electrical centres or fuse-holders).

Key topics and technical requirements

The standard organizes its technical content into clear topics and test categories. Major items include:

• Terms and definitions specific to automotive circuit breakers (e.g., absolute breaking capacity, breaking capacity, trip-free vs cycling trip free, reset types).
• Marking, labelling and colour coding requirements to ensure traceability and safe installation.
• General test conditions and performance requirements that apply across device types.
• Electrical performance tests:
  • Voltage drop measurement
  • Operating time rating and current step testing
  • Absolute breaking capacity and repeated breaking capacity
  • No‑current trip and reset temperature checks
• Thermal and mechanical tests:
  • Maximum housing temperature assessment
  • Strength of terminals (mechanical load tests)
  • Endurance (operational lifecycle)
• Environmental and durability requirements aligned to automotive conditions:
  • Mechanical loads, climatic loads and chemical exposure (referencing ISO 16750 series)
  • Dielectric strength and insulation integrity
• Supporting information: Annex A (cycling profiles) and Annex B (test circuit) provide test sequences and circuits used in verification.

Practical applications - who uses ISO 10924-1:2016

This standard is used by organizations involved in the design, manufacture, testing and selection of automotive circuit breakers:

• Automotive OEMs and system engineers specifying overcurrent protection
• Component manufacturers and suppliers validating product performance
• Test laboratories performing compliance and type testing
• Regulatory and procurement teams requiring harmonized test evidence
• Design engineers integrating 12 V, 24 V, 48 V or 450 V d.c. protection into vehicle electrical architectures

ISO 10924-1 helps ensure reliable, repeatable performance of circuit breakers under realistic vehicle operating and environmental conditions.

Related standards

ISO 10924-1 references and is intended to be used with other standards, including:

• ISO 10924 (other parts: user’s guide, device-specific parts)
• ISO 16750 series (environmental testing for automotive electrical/electronic equipment)
• ISO 8820 series (fuse-links definitions and tests)
• ISO 6722-1 (single‑core cable requirements)
• IEC 60068-2-70 (abrasion of markings)

By following ISO 10924-1:2016, manufacturers and test labs can align automotive circuit breaker design and verification with internationally recognized definitions and general test procedures.