ISO 10924-1:2016

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 10924-1
ISO/TC 22/SC 32
Road vehicles — Circuit breakers —
Secretariat: JISC
Voting begins
Part 1:
on: 2015-10-16
Definitions and general test
Voting terminates
requirements
on: 2015-12-16
Véhicules routiers — Coupe-circuits —
Partie 1: Définitions et exigences d’essais générales
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OF ANY RELEVANT PATENT RIGHTS OF WHICH
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DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 10924-1:2015(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
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LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
©
NATIONAL REGULATIONS. ISO 2015

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ISO/FDIS 10924-1:2015(E)

COPYRIGHT PROTECTED DOCUMENT
© 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
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ii © ISO 2015 – All rights reserved

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ISO/FDIS 10924-1:2015(E)

Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Marking, labelling and colour coding . 5
5 Tests and requirements . 5
5.1 General . 5
5.1.1 General test conditions . 5
5.1.2 General performance requirements . 6
5.2 Voltage drop . 6
5.2.1 Purpose . 6
5.2.2 Test . 6
5.2.3 Requirement . 6
5.3 Maximum housing temperature . 6
5.3.1 Purpose . 6
5.3.2 Test . 6
5.3.3 Requirement . 6
5.4 Environmental conditions . 7
5.4.1 Purpose . 7
5.4.2 Mechanical loads . . 7
5.4.3 Climatic loads. 7
5.4.4 Chemical loads . 7
5.5 Operating time rating . 7
5.5.1 Purpose . 7
5.5.2 Test . 8
5.5.3 Requirement . 8
5.6 Current steps . 8
5.6.1 Purpose . 8
5.6.2 Test . 8
5.6.3 Requirement . 8
5.7 No current trip and reset temperature . 8
5.7.1 Purpose . 8
5.7.2 Test . 8
5.7.3 Requirement . 9
5.8 Absolute breaking capacity . 9
5.8.1 Purpose . 9
5.8.2 Test . 9
5.8.3 Requirement . 9
5.9 Breaking capacity . 9
5.9.1 Purpose . 9
5.9.2 Test .10
5.9.3 Requirement .10
5.10 Strength of terminals .10
5.10.1 Purpose .10
5.10.2 Test .11
5.10.3 Requirement .11
5.11 Endurance .11
5.11.1 Purpose .11
5.11.2 Test .11
5.11.3 Requirement .11
5.12 Dielectric strength.12
5.12.1 Purpose .12
5.12.2 Test .12
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ISO/FDIS 10924-1:2015(E)

5.12.3 Requirement .12
Annex A (informative) Cycling profiles .13
Annex B (informative) Test circuit .15
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ISO/FDIS 10924-1:2015(E)

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
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
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
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
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
constitute an endorsement.
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, Electrical
and electronic components and general system aspects.
This second edition cancels and replaces the first edition (ISO 10924-1:2009), 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 CB 15
— Part 5: Circuit breakers with rated voltage of 450 V
© ISO 2015 – All rights reserved v

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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 10924-1:2015(E)
Road vehicles — Circuit breakers —
Part 1:
Definitions and general test requirements
1 Scope
This part of ISO 10924 defines terms and specifies general test requirements for circuit breakers for
use in road vehicles with a nominal voltage of 12 V d.c., 24 V d.c, 48 V d.c. and 450 V d.c.
This part of ISO 10924 is intended to be used in conjunction with other parts of ISO 10924. The
numbering of its clauses corresponds to that of this part of ISO 10924 whose requirements are
applicable, except where modified by requirements particular to this part of ISO 10924.
This part of ISO 10924 is not applicable to circuit breaker holders (electrical centres or fuse-holders)
used in vehicles.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 6722–1, Road vehicles — 60 V and 600 V single-core cables — Part 1: Dimensions, test methods and
requirements for copper conductor cables
ISO 8820–1, Road vehicles — Fuse-links — Part 1: Definitions and general test requirements
ISO 8820–3, Road vehicles — Fuse-links — Part 3: Fuse-links with tabs (blade type) Type C (medium), Type
E (high current) and Type F (miniature)
ISO 16750–1, Road vehicles — Environmental conditions and testing for electrical and electronic
equipment — Part 1: General
ISO 16750–3, Road vehicles — Environmental conditions and testing for electrical and electronic
equipment — Part 3: Mechanical loads
ISO 16750–4, Road vehicles — Environmental conditions and testing for electrical and electronic
equipment — Part 4: Climatic loads
ISO 16750–5, Road vehicles — Environmental conditions and testing for electrical and electronic
equipment — Part 5: Chemical loads
IEC 60068–2–70; Environmental testing — Part 2: Tests — Test Xb: Abrasion of markings and letterings
caused by rubbing of fingers and hands
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 16750-1, ISO 8820-1 and the
following apply.
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ISO/FDIS 10924-1:2015(E)

3.1
absolute breaking capacity
value of prospective breaking current that a circuit breaker is capable of breaking at least once at U
Smax
under prescribed conditions of use and behaviour
3.2
breaking capacity
I
B
value of prospective breaking current a circuit breaker is capable of breaking several times at U
Smax
under prescribed conditions of use and behaviour
3.3
circuit breaker
overcurrent protection device that mechanically interrupts the circuit reversibly, responsive to
electric current
Note 1 to entry: The test fixture for the circuit breaker may be identical to the test fixture as described in the
appropriate part of ISO 8820; however, some circuit breaker designs do not require a separate test fixture as the
cables are directly connected to the circuit breaker terminals.
3.4 Circuit breaker components
3.4.1
housing
electrically non-conductive mechanical support for conductive and non-conductive parts of the circuit
breaker (3.3)
3.4.2
terminal
part of the circuit breaker (3.3) which makes the electrical connection in the electrical circuit
3.4.3
time delayed element
active part that acts depending on the current and causes the reversible interruption of the circuit in
the case of an overcurrent
3.5 Circuit breaker features
3.5.1
reset mechanism
provides a user interface in a manual reset circuit breaker (3.3) for resetting the device after an
overcurrent condition
3.5.2
snap-action mechanism
ensures that the contact closing speed by mechanical reset is independent of the speed of operation of
the reset mechanism (3.5.1)
3.5.3
switching mechanism
provides the ability to switch off the circuit breaker (3.3) by mechanical means
3.5.4
trip mechanism
comprises a time delayed actuator and mechanical components
3.5.4.1
cycling trip free
circuit breaker mechanism that cycles to open and close the contact(s) repeatedly if the actuator is
maintained in the “ON” position in case of overcurrent
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ISO/FDIS 10924-1:2015(E)

3.5.4.2
fully trip free
circuit breaker mechanism that will cause the moving contact(s) to open and remain open, even if the
actuator is maintained in the “ON” position in case of overcurrent
3.5.5
trip free mechanism
prevents the switching mechanism (3.5.3) from being defeated by forcibly holding the actuator “ON”
position, i.e. cannot be held closed against an overload
3.6 Circuit breaker types
3.6.1
type I – automatic reset
provides the reversal of an overcurrent condition after a cool-down period without any manual activity
required by a user
3.6.2
type II – electrically reset
has a secondary heating circuit which, after an overcurrent condition occurs, creates heat internally
upon the time delayed element (3.4.3) of the circuit breaker (3.3) to keep it from reversing as long as
electrical system voltage and a small current flow (<1,0 A) is available, reset function is accomplished
by removing all electrical power supplied to the circuit breaker until the internal thermal element cools
do
...