ISO 10924-5:2025

Overview

ISO 10924-5:2025 - Road vehicles - Circuit breakers - Part 5 specifies requirements for bolt-type circuit breakers with a rated voltage of 450 V (DC) for use in road vehicles. The standard defines the rated current (≤ 300 A), breaking capacity (6 000 A), required test procedures, performance criteria, dimensions, and marking/colour coding for this circuit breaker type. It is intended to be used together with ISO 10924-1 and ISO 10924-2; clause numbering aligns with ISO 10924-1 except where modified.

Key topics and technical requirements

• Rated parameters: 450 V (DC) rated voltage, current ratings up to 300 A, breaking capacity 6 000 A.
• Performance tests and requirements covering:
  • Voltage drop (energy consumption and temperature rise)
  • Maximum housing temperature
  • Operating time-rating at multiple current multiples (e.g., 1.0, 1.35, 1.5, 2.0, 4.0, 6.0 × IR)
  • Current step tests, no-current trip and reset temperature
  • Absolute breaking capacity and breaking capacity tests
  • Strength of terminals, endurance, dielectric strength, pulse tests
  • Environmental and mechanical loads (climatic, vibration, shock, free-fall, chemical loads) per ISO 16750-4
• Test setup requirements: electrical test fixtures per ISO 8820-8, connection resistance ≤ 1 mΩ, ambient range −40 °C to 85 °C (Code G).
• Dimensions and labelling: specified dimensions, colour-code mapping for rated currents (15 A–300 A) to support identification and interchangeability.
• Test cable sizes: specified conductor cross-sections for each rated current to ensure comparable test results (based on ISO 6722-1 thick-wall copper cables).

Applications

• Ensures safe, repeatable performance of 450 V bolt circuit breakers used in high-voltage road-vehicle electrical systems (power distribution, battery protection, traction and auxiliary circuits).
• Guides design verification, type testing and qualification for manufacturers, automotive OEMs, and component suppliers.
• Provides test laboratories and compliance teams with a standardized test sequence and acceptance criteria for safety and durability assessments.

Who should use this standard

• Circuit breaker manufacturers and suppliers
• Automotive design engineers and system integrators
• Test and certification laboratories
• Quality, safety and regulatory compliance teams

Related standards

• ISO 10924-1 (Definitions and general test requirements)
• ISO 10924-2 (Recommendations for users)
• ISO 6722-1 (Road vehicle cables)
• ISO 8820-8 / ISO 8820-7 (Fuse and contact test fixture references)
• ISO 16750-4 (Climatic loads)

Keywords: ISO 10924-5:2025, circuit breakers, 450 V, bolt circuit breaker, road vehicles, breaking capacity, rated current, vehicle electrical systems, test procedures, performance requirements.