ISO 8820-2:2014
(Main)Road vehicles — Fuse-links — Part 2: User guidelines
Road vehicles — Fuse-links — Part 2: User guidelines
ISO 8820-2:2014 gives guidance for the choice and application of automotive fuse-links which are defined in the other parts of the ISO 8820 series. It describes the various parameters which have to be taken into account when selecting fuse-links. Fuse-links according to ISO 8820 are intended for electrical cable protection. If these types of fuse-links are to be used for electrical component protection, it should be agreed between customer and supplier. ISO 8820-2:2014 is intended to be used in conjunction with the other parts of ISO 8820.
Véhicules routiers — Liaisons fusibles — Partie 2: Guide de l'utilisateur
General Information
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 8820-2
Third edition
2014-02-15
Road vehicles — Fuse-links —
Part 2:
User guidelines
Véhicules routiers — Liaisons fusibles —
Partie 2: Guide de l’utilisateur
Reference number
ISO 8820-2:2014(E)
©
ISO 2014
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ISO 8820-2:2014(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2014
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.
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Published in Switzerland
ii © ISO 2014 – All rights reserved
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ISO 8820-2:2014(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Rated voltage and system voltage . 1
5 Rated current and continuous current. 1
6 Cold resistance . 1
7 Current and conductors . 3
8 Current and contact resistance . 4
9 Current and ambient temperature . 4
10 Cable protection versus time-current characteristics. 5
11 Selectivity . 7
12 Replacement of fuse-links . 7
13 Voltage peaks during opening of fuse-links . 7
14 Inrush withstand characteristics of fuse-links . 7
15 Electromagnetic compatibility (EMC) . 8
Annex A (informative) Parameters for the selection of fuse-links in road vehicles .9
Annex B (normative) Selection criteria for fuse-links and cables .10
© ISO 2014 – All rights reserved iii
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ISO 8820-2:2014(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 3, Electrical
and electronic equipment.
This third edition cancels and replaces the second edition (ISO 8820-2:2005), which has been technically
revised.
ISO 8820 consists of the following parts, under the general title Road vehicles — Fuse-links:
— Part 1: Definitions and general test requirements
— Part 2: User guidelines
— Part 3: Fuse-links with tabs (blade type) Type C (medium), Type E (high currents) and Type F (miniature)
— Part 4: Fuse-links with female contacts (Type A) and bolt-in contacts (Type B) and their test fixtures
— Part 5: Fuse-links with axial terminals (Strip fuse-links) Types SF30 and SF51 and test fixtures
— Part 6: Single-bolt fuse-links
— Part 7: Fuse-links with tabs (Type G) with rated voltage of 450 V
— Part 8: Fuse-links with bolt-in contacts (Types H and J) with a rated voltage of 450 V
— Part 9: Fuse-links miniature low profile (Type K)
1)
— Part 10: Road vehicles — Fuse — Part 10: Fuse-links with tabs Type L (high current miniature)
1) To be published.
iv © ISO 2014 – All rights reserved
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INTERNATIONAL STANDARD ISO 8820-2:2014(E)
Road vehicles — Fuse-links —
Part 2:
User guidelines
1 Scope
This part of ISO 8820 gives guidance for the choice and application of automotive fuse-links which are
defined in the other parts of this International Standard. It describes the various parameters which
have to be taken into account when selecting fuse-links.
Fuse-links according to ISO 8820 are intended for electrical cable protection. If these types of fuse-links
are to be used for electrical component protection, it should be agreed between customer and supplier.
It is intended to be used in conjunction with the other parts of ISO 8820.
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 8820-1, Road vehicles — Fuse-links — Part 1: Definitions and general test requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions in ISO 8820-1 apply.
4 Rated voltage and system voltage
The fuse rated voltage shall always be higher than the nominal voltage of the electrical system of the
vehicle to allow for possible overvoltage conditions.
5 Rated current and continuous current
The rated current (I ) is the current used for identifying the fuse-link.
R
The continuous current (I ) in Figure 1 is the maximum current flowing continuously through the circuit
C
(fuse-link, terminals, holder, and cables) at a maximum ambient temperature. The continuous current
is lower than the rated current.
6 Cold resistance
The cold resistance is the resistance of a fuse-link without self-heating at room temperature (RT). It can
be calculated by the drop voltage measured, between the measuring points of the fuse-link (specified
in the appropriate part of ISO 8820 according to the type of the fuse), at a certain current, typically
measured at 10 % of fuse rated current.
The spread of fuse-link cold resistance due to volume production results in a spread in power dissipation
and a spread in time-current characteristic (see Figure 2).
© ISO 2014 – All rights reserved 1
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ISO 8820-2:2014(E)
Figures 2 and 3 show the variation of operating time and voltage drop versus cold resistance for a given
test current.
Key
Y operating time (t)
X current (I)
1 time-current characteristic
Figure 1 — Rated current, continuous current, and time-current characteristic
The rise of the temperature in the circuit depends on the current and time.
Key
Y operating time
X cold resistance
Figure 2 — Cold resistance versus operating time
2 © ISO 2014 – All rights reserved
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ISO 8820-2:2014(E)
Key
Y voltage drop
X cold resistance
Figure 3 — Cold resistance versus voltage drop
7 Current and conductors
The temperature rise of a conductor is a function of current, conductor cross section, and time duration.
For system application, other influences, e.g. ambient temperature, conducting and isolating material,
strands, have to be taken into account also. Figure 4 shows stabilized temperature rise for various
conductor cross sections.
© ISO 2014 – All rights reserved 3
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ISO 8820-2:2014(E)
Key
Y conductor temperature
X’ conductor session section
X current (I)
Figure 4 — Conductor temperatures for different conductor cross sections versus current
8 Current and contact resistance
A higher contact resistance of mated terminals leads to a temperature rise and reduced thermal
conduction from the fuse-link. The temperature of the fuse-link terminal will increase and the continuous
current for the application has to be derated.
A temperature rise test can be conducted using fuse-links, fuse holders, and connections as specified
by the vehicle manufacturer. At a specified test current, the temperature of the connections shall be
measured at the points specified in the appropriate part of the ISO 8820 according to the type of the
fuse. After thermal equilibrium has been achieved, the temperature rise of the connection shall not
exceed the limits as specified for terminals and cable.
9 Current and ambient temperature
All components of a circuit and their parts have their own characteristic thermal curve as shown in
Figure 5.
Each component in a circuit has an upper temperature l
...
DRAFT INTERNATIONAL STANDARD ISO/DIS 8820-2
ISO/TC 22/SC 3 Secretariat: DIN
Voting begins on Voting terminates on
2012-02-27 2012-07-27
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION • МЕЖДУНАРОДНАЯ ОРГАНИЗАЦИЯ ПО СТАНДАРТИЗАЦИИ • ORGANISATION INTERNATIONALE DE NORMALISATION
Road vehicles — Fuse-links —
Part 2:
User's guide
Véhicules routiers — Liaisons fusibles —
Partie 2: Guide de l'utilisateur
[Revision of second edition (ISO 8820-2:2005)]
ICS 43.040.10
To expedite distribution, this document is circulated as received from the committee
secretariat. ISO Central Secretariat work of editing and text composition will be undertaken at
publication stage.
Pour accélérer la distribution, le présent document est distribué tel qu'il est parvenu du
secrétariat du comité. Le travail de rédaction et de composition de texte sera effectué au
Secrétariat central de l'ISO au stade de publication.
THIS DOCUMENT IS A DRAFT CIRCULATED FOR COMMENT AND APPROVAL. IT IS THEREFORE SUBJECT TO CHANGE AND MAY NOT BE
REFERRED TO AS AN INTERNATIONAL STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS BEING ACCEPTABLE FOR INDUSTRIAL, TECHNOLOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT, WITH THEIR COMMENTS, NOTIFICATION OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPORTING DOCUMENTATION.
© International Organization for Standardization, 2012
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ISO/DIS 8820-2
Copyright notice
This ISO document is a Draft International Standard and is copyright-protected by ISO. Except as permitted
under the applicable laws of the user’s country, neither this ISO draft nor any extract from it may be
reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic,
photocopying, recording or otherwise, without prior written permission being secured.
Requests for permission to reproduce should be addressed to either ISO at the address below or ISO’s
member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Reproduction may be subject to royalty payments or a licensing agreement.
Violators may be prosecuted.
ii © ISO 2012 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/DIS 8820-2
Contents Page
Foreword . iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Rated voltage and system voltage . 1
5 Rated current and continuous current . 1
6 Cold resistance . 1
7 Current and conductors . 3
8 Current contact resistance . 4
9 Current and ambient temperature . 4
10 Cable protection versus time-current characteristics . 4
11 Selectivity . 6
12 Replacement of fuse-links . 6
13 Voltage peaks during opening of fuse-links . 6
14 Inrush withstand characteristics of fuse-links . 6
15 Electromagnetic compatibility (EMC) . 7
Annex A (normative) Parameters for the selection of fuse-links in road vehicles . 8
Annex B (informative) Selection criteria for fuse-links and cables . 9
© ISO 2012 – All rights reserved iii
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ISO/DIS 8820-2
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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 8820-2 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 3, Electrical
and electronic equipment.
This third edition cancels and replaces the second edition (2005) which has been technically revised.
ISO 8820 consists of the following parts, under the general title Road vehicles — Fuse-links:
⎯ Part 1: Definitions and general test requirements
⎯ Part 2: User's guide
⎯ Part 3: Fuse-links with tabs (blade type) Type C (medium), Type E (high currents) and Type F (miniature)
⎯ Part 4: Fuse-links with female contacts (Type A) and bolt-in contacts (Type B) and their test fixtures
⎯ Part 5: Fuse-links with axial terminals (strip fuse-links) Type SF30 and SF51 and test fixture
⎯ Part 6: Single bolt fuse-links
⎯ Part 7: Fuse-links with a rated voltage of 450 V (Type G)
⎯ Part 8: Fuse-links with bolt-in contacts (Type H and J) with a rated voltage of 450 V
⎯ Part 9: Fuse-links miniature low profile (Type K)
iv © ISO 2012 – All rights reserved
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DRAFT INTERNATIONAL STANDARD ISO/DIS 8820-2
Road vehicles — Fuse-links —
Part 2:
User's guide
1 Scope
This Part of ISO 8820 gives guidance for the choice and application of automotive fuse-links (see Annex A)
which are defined in Part 3 and above of this Standard. It describes the various parameters which have to be
taken into account when selecting fuse-links.
Fuse-links according to ISO 8820 are intended for electrical cable protection. If these type of fuse-links shall
be used for electrical component protection, it shall be agreed between customer and supplier.
It is intended to be used in conjunction with the other parts of ISO 8820.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 8820-1, Road vehicles - Fuses — Part 1: Definitions and general test requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8820-1 apply.
4 Rated voltage and system voltage
The fuse rated voltage shall always be higher than the nominal voltage of the electrical system of the vehicle,
to allow for possible overvoltage conditions.
5 Rated current and continuous current
The rated current (I ) is the current used for identifying the fuse-link.
R
The continuous current (I ) in Figure 1 is the maximum current flowing continuously through the circuit (fuse-
C
link, terminals, holder and cables) at a maximum ambient temperature. The continuous current is lower than
the rated current.
6 Cold resistance
The cold resistance is the resistance of a fuse-link without self-heating at room temperature (RT). It can be
calculated by the drop voltage measured, between the measuring points of the fuse-link (specified in the
appropriate part of the ISO 8820 according to the type of the fuse) , at a certain current, typically measured at
10% of fuse rated current.
The spread of fuse-link cold resistance due to volume production results in a spread in power dissipation and
a spread in time-current characteristic, see Figure 2.
Figures 2 and 3 show the variation of operating time and voltage drop versus cold resistance for a given test
current.
© ISO 2012 – All rights reserved 1
---------------------- Page: 5 ----------------------
ISO/DIS 8820-2
Key: Y = Operating time (t)
X = Current (I)
1 = Time-current characteristic
Figure 1 — Rated current, continuous current and time-current characteristic
The rise of the temperature in the circuit depends on current and time.
Key: Y = Operating time
X = Cold resistance
Figure 2 — Cold resistance versus operating time
2 © ISO 2012 – All rights reserved
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ISO/DIS 8820-2
Key: Y = Voltage drop
X = Cold resistance
Figure 3 — Cold resistance versus voltage drop
7 Current and conductors
The temperature rise of a cable is a function of current, conductor cross section and time duration. For system
application, other influences e.g. ambient temperature, conducting and isolating material, strands, have to be
taken into account, too. Figure 4 shows stabilised temperature rise for various conductor cross sections.
Key: Y = Conductor temperature
X' = Conductor session section
X = Current (I)
Figure 4 — Conductor temperatures for different conductor cross sections versus current
© ISO 2012 – All rights reserved 3
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ISO/DIS 8820-2
8 Current contact resistance
A higher resistance of mated terminals will result in a temperature rise and reduced thermal conduction away
from the fuse-link. Hence, the temperature of the fuse-link terminal will be higher and the continuous current
for the application lower.
A temperature rise test may be conducted using fuse-links, fuse holders and connections as specified by the
vehicle manufacturer. At a specified test current the temperature of the connections shall be measured at the
points specified in the appropriate part of the ISO 8820 according to the type of the fuse. After thermal
equilibrium has been achieved, the temperature rise of the connection shall not exceed the limits
...
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