ISO 10924-4:2015

Road vehicles - Circuit breakers - Part 4: Medium circuit breakers with tabs (Blade type), Form CB15

ISO 10924-4:2015 specifies medium circuit breakers with tabs (Blade type), Form CB15, for use in road vehicles. It establishes, for this circuit breaker form, the rated current, test procedures, performance requirements and dimensions. ISO 10924-4:2015 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 part of ISO 10924. ISO 10924-4:2015 is applicable to circuit breakers with a rated voltage of 14 V d.c. or 28 V d.c. or 58 V d.c., a current rating of no greater than 40 A and a breaking capacity of 2 000 A, intended for use in road vehicles with a nominal voltage of 12 V d.c. or 24 V d.c. or 48 V d.c. Circuit breakers differ in terms of dimensions and functions, e.g. electrically reset, automatic reset, manual reset and switchable. NOTE This type of circuit breaker is intended to be used in applications such as medium fuse-links in accordance with ISO 8820‑3. While the tab dimensions and current ratings can be the same, there might be differences in performance, which it is advisable that the user of these products take into consideration.

Véhicules routiers — Coupe-circuits — Partie 4: Coupe-circuits moyens à languettes (de type lame), forme CB15

General Information

• Status: Published
• Publication Date: 19-Jul-2015
• 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/WG 5 - Fuses and circuit breakers
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 01-Apr-2025
• Completion Date: 13-Dec-2025

Relations

• Revised: ISO 10924-4:2025 - Road vehicles - Circuit breakers - Part 4: Medium circuit breakers with tabs (Blade type), Form CB15
• Effective Date: 06-Jun-2022
• Revises: ISO 10924-4:2009 - Road vehicles - Circuit breakers - Part 4: Medium circuit breakers with tabs (Blade type), Form CB15
• Effective Date: 25-May-2013

Overview

ISO 10924-4:2015 specifies medium circuit breakers with tabs (blade type), Form CB15, for use in road vehicles. It defines the rated current, dimensions, test procedures and performance requirements for CB15 blade-type automotive circuit breakers. This part is intended to be used alongside ISO 10924‑1 (definitions and general test requirements) and ISO 10924‑2 (user’s guide).

Key parameters covered:

• Rated voltages: 14 V d.c., 28 V d.c., 58 V d.c.
• Intended nominal vehicle systems: 12 V, 24 V, 48 V d.c.
• Maximum current rating: ≤ 40 A
• Breaking capacity: 2 000 A

Key topics and technical requirements

ISO 10924-4 defines test methods and performance criteria specific to CB15 blade circuit breakers. Major technical topics include:

• Test sequence plan and conditions - tests follow sequences aligned with ISO 10924-1; electrical test fixture Type C per ISO 8820‑3 with maximum connection resistance 0.8 mΩ.
• Environmental range - ambient operating temperatures −40 °C to 85 °C (Code G, ISO 16750‑4).
• Electrical performance tests:
  • Voltage drop measurement across tabs at 0.7 × rated current.
  • Operating time-rating and multiple current-step tests (various multiples of rated current).
  • Absolute breaking capacity and breaking capacity tests up to the specified 2 000 A.
  • No-current trip / reset temperatures, dielectric strength and endurance.
• Mechanical tests - terminal strength, vibration, shock and free-fall as required.
• Dimensions, marking and colour coding - standard tab dimensions and colour code per rated current to aid identification (examples: 5 A tan, 10 A red, 20 A yellow, 40 A orange).
• Test cable sizes - specified per rated current (see standard Table 3), using conductor materials per ISO 6722‑1.

Note: CB15 breakers can be electrically reset, automatic reset, manual reset or switchable. Performance can differ from blade-type fuse-links (ISO 8820‑3) even when tab dimensions and current ratings match.

Practical applications and users

ISO 10924-4 is essential for:

• Automotive electrical and electronic component manufacturers (design, production, interchangeability)
• OEMs and vehicle system engineers (component selection and system protection design)
• Test laboratories and certification bodies (type testing and compliance verification)
• Aftermarket and fleet maintenance teams (replacement and compatibility assessment)

Typical uses: medium-current circuit protection in passenger cars, commercial vehicles, off-highway vehicles and other road vehicles where standardized blade-type medium circuit breakers are required.

Related standards

• ISO 10924-1: Definitions and general test requirements
• ISO 10924-2: User’s guide
• ISO 10924-3: Miniature circuit breakers, Form CB11
• ISO 8820-3: Fuse links with tabs (Blade type)
• ISO 6722-1: Road vehicle cables (conductor specs)
• ISO 16750-4: Environmental/climatic testing

Keywords: ISO 10924-4:2015, medium circuit breakers, Form CB15, blade type, automotive circuit protection, rated current, breaking capacity, voltage drop, automotive standards.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 10924-4
Second edition
2015-08-01
Road vehicles — Circuit breakers —
Part 4:
Medium circuit breakers with tabs
(Blade type), Form CB15
Véhicules routiers — Coupe-circuits —
Partie 4: Coupe-circuits moyens à languettes (de type lame), forme
CB15
Reference number
©
ISO 2015
© ISO 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2015 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Marking, labelling and colour coding . 1
5 Tests and requirements . 2
5.1 General . 2
5.1.1 General test conditions . 2
5.1.2 Test sequence plan . 2
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 . 4
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 . 5
5.8.1 Purpose . 5
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 . 6
5.11 Endurance . 6
5.11.1 Purpose . 6
5.11.2 Tests . 6
5.11.3 Requirements . 7
5.12 Dielectric strength. 7
5.12.1 Purpose . 7
5.12.2 Tests . 7
5.12.3 Requirement . 7
6 Dimensions and designation example . 7
6.1 Dimensions . 7
6.1.1 Category A . 8
6.1.2 Category B. 9
6.1.3 Category C . 9
6.1.4 Category D .10
6.1.5 Category E .10
6.1.6 Category F and G .11
6.1.7 Category H .11
6.1.8 Category J .12
6.1.9 Category K .12
6.2 Designation example .13
Bibliography .14
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
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on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
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For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 22, Road vehicles, Subcommittee SC 32, Electric
and electronic components and general system aspects.
This second edition cancels and replaces the first edition (ISO 10924-4:2009), which has been
technically revised.
ISO 10924 consists of the following parts, under the general title Road vehicles — Circuit breakers:
— Part 1: Definitions and general test requirements
— Part 2: User’s guide
— Part 3: Miniature circuit breakers with tabs (Blade type), Form CB11
— Part 4: Medium circuit breakers with tabs (Blade type), Form CB15
— Part 5: Circuit breakers with tabs with rated voltage of 450 V
iv © ISO 2015 – All rights reserved

INTERNATIONAL STANDARD ISO 10924-4:2015(E)
Road vehicles — Circuit breakers —
Part 4:
Medium circui
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