ISO 10924-5:2025

Road vehicles - Circuit breakers - Part 5: Circuit breakers with bolt with rated voltage of 450 V

This document specifies circuit breakers with a rated voltage of 450 V for use in road vehicles. It establishes, for this circuit breaker type, the rated current, test procedures, performance requirements and dimensions. This document is intended to be used in conjunction with ISO 10924-1 and with ISO 10924-2. The numbering of its clauses corresponds to that of ISO 10924-1 whose requirements are applicable, except where modified by requirements particular to this document. This document is applicable to circuit breakers with a rated voltage of 450 V (DC), a current rating of no greater than 300 A and a breaking capacity of 6 000 A.

Véhicules routiers — Coupe-circuits — Partie 5: Coupe-circuit moyen à boulon avec une tension nominale de 450 V

General Information

• Status: Published
• Publication Date: 31-Mar-2025
• ICS: 43.040.10 - Electrical and electronic equipment
• Technical Committee: ISO/TC 22/SC 32 - Electrical and electronic components and general system aspects
• Drafting Committee: ISO/TC 22/SC 32 - Electrical and electronic components and general system aspects
• Current Stage: 6060 - International Standard published
• Start Date: 01-Apr-2025
• Due Date: 24-Nov-2024
• Completion Date: 31-Mar-2025

Relations

• Revises: ISO 10924-5:2016 - Road vehicles - Circuit breakers - Part 5: Circuit breakers with bolt with rated voltage of 450 V
• Effective Date: 06-Jun-2022

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.

Standards Content (Sample)

International
Standard
ISO 10924-5
Second edition
Road vehicles — Circuit breakers —
2025-03
Part 5:
Circuit breakers with bolt with
rated voltage of 450 V
Véhicules routiers — Coupe-circuits —
Partie 5: Coupe-circuit moyen à boulon avec une tension
nominale de 450 V
Reference number
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Marking, labelling and colour coding . 2
5 Tests and requirements . 2
5.1 General .2
5.1.1 General test conditions .2
5.1.2 Test sequence plan .3
5.1.3 Test cable sizes .3
5.2 Voltage drop .4
5.2.1 Purpose .4
5.2.2 Tests .4
5.2.3 Requirements .4
5.3 Maximum housing temperature .5
5.4 Environmental conditions .5
5.5 Operating time-rating .5
5.5.1 Purpose .5
5.5.2 Tests .5
5.5.3 Requirements .5
5.6 Current steps .5
5.7 No current trip and reset temperature .5
5.8 Absolute breaking capacity .6
5.8.1 Purpose .6
5.8.2 Tests .6
5.8.3 Requirements .6
5.9 Breaking capacity .6
5.9.1 Purpose .6
5.9.2 Tests .6
5.9.3 Requirements .6
5.10 Strength of terminals.7
5.10.1 Purpose .7
5.10.2 Tests .7
5.10.3 Requirements .7
5.11 Endurance .7
5.11.1 Purpose .7
5.11.2 Tests .7
5.11.3 Requirements .7
5.12 Dielectric strength .7
5.12.1 Purpose .7
5.12.2 Tests .7
5.12.3 Requirement .8
5.13 Pulse test.8
5.13.1 Purpose .8
5.13.2 Test . . .8
5.13.3 Requirement .8
6 Dimensions and designation example (Figure 2 and Table 8). 9

iii
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