ISO 10924-3:2015

Overview

ISO 10924-3:2015 - Road vehicles - Circuit breakers - Part 3: Miniature circuit breakers with tabs (Blade type), Form CB11 - specifies performance, dimensions and test procedures for blade-type miniature circuit breakers used in road vehicles. It applies to breakers with rated voltages of 14 V and/or 28 V, current ratings up to 30 A, and an absolute breaking capacity of 2 000 A, intended for nominal 12 V and/or 24 V vehicle electrical systems. This part is to be used together with ISO 10924‑1 (definitions and general tests) and ISO 10924‑2 (user’s guide).

Key topics and technical requirements

• Scope & form factor: Defines Form CB11 blade/tab miniature circuit breakers including electrically reset, automatic reset, manual reset and switchable variants.
• Rated values: Rated voltage 14/28 V; current ratings ≤ 30 A; breaking capacity up to 2 000 A.
• Dimensions & designation: Standardized tab dimensions and part designation examples for compatibility with blade-type fuse installations.
• Test methods and sequence: Detailed test sequence plan covering:
  • Voltage drop measurement (at 0.7·IR across tabs) and maximum permitted millivolt drops per rating.
  • Operating time‑rating and time‑current characteristics at multiple test currents (e.g., 0.7 I R, 1.0 I R, 1.35 I R, 2.0 I R).
  • Absolute and rated breaking capacity tests (tested at 2 000 A).
  • Endurance, dielectric strength, terminal mechanical strength, and environmental tests (climatic, vibration, shock, free-fall, chemical).
• Environmental class: Ambient temperature range −40 °C to 85 °C (Code G, per ISO 16750‑4).
• Test cable sizes: Recommended test conductor cross-sections per rated current (e.g., 5 A → 0.5 mm², 30 A → 4.0 mm²) to ensure consistent comparative testing.

Practical applications and users

ISO 10924-3 is intended for:

• Automotive OEMs specifying in-vehicle overcurrent protection for 12 V/24 V systems.