IEC TR 60890:2014
(Main)A method of temperature-rise verification of low-voltage switchgear and controlgear assemblies by calculation
A method of temperature-rise verification of low-voltage switchgear and controlgear assemblies by calculation
IEC TR 60890:2014 specifies a method of temperature-rise verification of low-voltage switchgear and controlgear ASSEMBLIES by calculation. The method is applicable to enclosed ASSEMBLIES or partitioned sections of ASSEMBLIES without forced ventilation. It is not applicable where temperature rise verification to the relevant product standard of the IEC 61439 series has been established. This second edition cancels and replaces the first edition published in 1987 and its Amendment 1:1995. It constitutes a technical revision. This edition includes the following significant technical changes with respect to the last edition:
- alignment with IEC 61439-1:2011;
- revision of Annex B;
- general editorial review.
Méthode de vérification par calcul des échauffements pour les ensembles d'appareillage à basse tension
L'IEC TR 60890:2014 décrit une méthode de vérification par calcul des échauffements pour les ENSEMBLES d'appareillage à basse tension. La méthode est applicable aux ENSEMBLES sous enveloppe ou aux sections compartimentées des ENSEMBLES sans ventilation forcée. Elle n'est pas applicable lorsque la vérification de l'échauffement a été réalisée conformément à la norme produit de la série IEC 61439. Cette deuxième édition annule et remplace la première édition parue en 1987 et son Amendement 1:1995. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à la dernière édition:
- harmonisation avec l'IEC 61439-1:2011;
- révision de l'Annexe B;
- revue éditoriale générale.
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IEC TR 60890 ®
Edition 2.0 2014-05
TECHNICAL
REPORT
RAPPORT
TECHNIQUE
A method of temperature-rise verification of low-voltage switchgear and
controlgear assemblies by calculation
Méthode de vérification par calcul des échauffements pour les ensembles
d’appareillage à basse tension
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
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About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.
About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.
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The advanced search enables to find IEC publications by a More than 55 000 electrotechnical terminology entries in
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committee,…). It also gives information on projects, replaced clause of IEC publications issued since 2002. Some entries
and withdrawn publications. have been collected from earlier publications of IEC TC 37,
77, 86 and CISPR.
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IEC TR 60890 ®
Edition 2.0 2014-05
TECHNICAL
REPORT
RAPPORT
TECHNIQUE
A method of temperature-rise verification of low-voltage switchgear and
controlgear assemblies by calculation
Méthode de vérification par calcul des échauffements pour les ensembles
d’appareillage à basse tension
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX V
ICS 29.130.20 ISBN 978-2-8322-1566-1
– 2 – IEC TR 60890:2014 © IEC 2014
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Conditions for application . 7
5 Calculation . 8
5.1 Necessary information . 8
5.2 Calculation procedure . 8
5.2.1 General . 8
5.2.2 Determination of the effective cooling surface A of the enclosure . 8
e
5.2.3 Determination of the internal temperature rise ∆t of the air at mid-
0,5
height of the enclosure . 8
5.2.4 Determination of the internal temperature rise ∆t of air at the top of
1,0
the enclosure . 9
5.2.5 Characteristic curve for temperature rise of air inside enclosure . 9
6 Evaluation of the design . 11
Annex A (informative) Examples for the calculation of the temperature-rise of air
inside the enclosures . 20
A.1 Example 1 . 20
A.2 Example 2 . 23
Annex B (informative) Operating current and power losses of conductors . 27
Bibliography . 32
Figure 1 – Temperature-rise characteristic curve for enclosures with
A exceeding 1,25 m . 10
e
Figure 2 – Temperature-rise characteristic curve for enclosures with A
e
not exceeding 1,25 m . 10
Figure 3 – Enclosure constant k for enclosures without ventilation openings, with an
effective cooling surface A > 1,25 m . 13
e
Figure 4 – Temperature distribution factor c for enclosures without ventilation openings
and with an effective cooling surface A > 1,25 m . 14
e
Figure 5 – Enclosure constant k for enclosures with ventilation openings and an
effective cooling surface A > 1,25 m . 15
e
Figure 6 – Temperature distribution factor c for enclosures with ventilation openings
and an effective cooling surface A > 1,25 m . 16
e
Figure 7 – Enclosure constant k for enclosures without ventilation openings and with
an effective cooling surface A ≤ 1,25 m . 17
e
Figure 8 – Temperature distribution factor c for enclosures without ventilation openings
and with an effective cooling surface A ≤ 1,25 m . 18
e
Figure 9 – Calculation of temperature rise of air inside enclosures . 19
Figure A.1 – Example 1, calculation for an enclosure with exposed side faces without
ventilation openings and without internal horizontal partitions . 20
Figure A.2 – Example 1, calculation for a single enclosure . 22
Figure A.3 – Example 2, calculation for an enclosure for wall-mounting with ventilation
openings . 23
Figure A.4 – Example 2, calculation for one enclosure half . 24
Figure A.5 – Example 2, calculation for an enclosure for wall-mounting with ventilation
openings . 26
Table 1 – Method of calculation, application, formulae and characteristics . 11
Table 2 – Symbols, units and designations . 12
Table 3 – Surface factor b according to the type of installation . 12
Table 4 – Factor d for enclosures without ventilation openings and with an effective
cooling surface A >1,25 m . 12
e
Table 5 – Factor d for enclosures with ventilation openings and an effective cooling
surface A >1,25 m . 12
e
Table B.1 – Operating current and power loss of single-core copper cables with a
permissible conductor temperature of 70 °C (ambient temperature inside the
enclosure: 55 °C) . 28
Table B.2 – Reduction factor k for cables with a permissible conductor temperature
of 70 °C (extract from IEC 60364-5-52:2009, Table B.52-14) . 29
Table B.3 – Operating current and power loss of bare copper bars with rectangular
cross-section, run horizontally and arranged with their largest face vertical (ambient
temperature inside the enclosure: 55 °C, temperature of the conductor 70 °C) . 30
Table B.4 – Factor k for different temperatures of the air inside the enclosure and/or
for the conductors . 31
– 4 – IEC TR 60890:2014 © IEC 2014
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
A METHOD OF TEMPERATURE-RISE VERIFICATION OF LOW-VOLTAGE
SWITCHGEAR AND CONTROLGEAR ASSEMBLIES BY CALCULATION
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred t
...
IEC TR 60890 ®
Edition 2.0 2014-05
TECHNICAL
REPORT
RAPPORT
TECHNIQUE
A method of temperature-rise verification of low-voltage switchgear and
controlgear assemblies by calculation
Méthode de vérification par calcul des échauffements pour les ensembles
d’appareillage à basse tension
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.
Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.
IEC Central Office Tel.: +41 22 919 02 11
3, rue de Varembé Fax: +41 22 919 03 00
CH-1211 Geneva 20 info@iec.ch
Switzerland www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.
About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.
IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
The stand-alone application for consulting the entire The world's leading online dictionary of electronic and
bibliographical information on IEC International Standards, electrical terms containing more than 30 000 terms and
Technical Specifications, Technical Reports and other definitions in English and French, with equivalent terms in 14
documents. Available for PC, Mac OS, Android Tablets and additional languages. Also known as the International
iPad. Electrotechnical Vocabulary (IEV) online.
IEC publications search - www.iec.ch/searchpub IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a More than 55 000 electrotechnical terminology entries in
variety of criteria (reference number, text, technical English and French extracted from the Terms and Definitions
committee,…). It also gives information on projects, replaced clause of IEC publications issued since 2002. Some entries
and withdrawn publications. have been collected from earlier publications of IEC TC 37,
77, 86 and CISPR.
IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Customer Service Centre - webstore.iec.ch/csc
details all new publications released. Available online and If you wish to give us your feedback on this publication or
also once a month by email. need further assistance, please contact the Customer Service
Centre: csc@iec.ch.
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.
A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.
Catalogue IEC - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
Application autonome pour consulter tous les renseignements
Le premier dictionnaire en ligne de termes électroniques et
bibliographiques sur les Normes internationales,
électriques. Il contient plus de 30 000 termes et définitions en
Spécifications techniques, Rapports techniques et autres
anglais et en français, ainsi que les termes équivalents dans
documents de l'IEC. Disponible pour PC, Mac OS, tablettes
14 langues additionnelles. Egalement appelé Vocabulaire
Android et iPad.
Electrotechnique International (IEV) en ligne.
Recherche de publications IEC - www.iec.ch/searchpub
Glossaire IEC - std.iec.ch/glossary
Plus de 55 000 entrées terminologiques électrotechniques, en
La recherche avancée permet de trouver des publications IEC
en utilisant différents critères (numéro de référence, texte, anglais et en français, extraites des articles Termes et
comité d’études,…). Elle donne aussi des informations sur les Définitions des publications IEC parues depuis 2002. Plus
projets et les publications remplacées ou retirées. certaines entrées antérieures extraites des publications des
CE 37, 77, 86 et CISPR de l'IEC.
IEC Just Published - webstore.iec.ch/justpublished
Service Clients - webstore.iec.ch/csc
Restez informé sur les nouvelles publications IEC. Just
Published détaille les nouvelles publications parues. Si vous désirez nous donner des commentaires sur cette
Disponible en ligne et aussi une fois par mois par email. publication ou si vous avez des questions contactez-nous:
csc@iec.ch.
IEC TR 60890 ®
Edition 2.0 2014-05
TECHNICAL
REPORT
RAPPORT
TECHNIQUE
A method of temperature-rise verification of low-voltage switchgear and
controlgear assemblies by calculation
Méthode de vérification par calcul des échauffements pour les ensembles
d’appareillage à basse tension
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX V
ICS 29.130.20 ISBN 978-2-8322-1566-1
– 2 – IEC TR 60890:2014 © IEC 2014
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Conditions for application . 7
5 Calculation . 8
5.1 Necessary information . 8
5.2 Calculation procedure . 8
5.2.1 General . 8
5.2.2 Determination of the effective cooling surface A of the enclosure . 8
e
5.2.3 Determination of the internal temperature rise ∆t of the air at mid-
0,5
height of the enclosure . 8
5.2.4 Determination of the internal temperature rise ∆t of air at the top of
1,0
the enclosure . 9
5.2.5 Characteristic curve for temperature rise of air inside enclosure . 9
6 Evaluation of the design . 11
Annex A (informative) Examples for the calculation of the temperature-rise of air
inside the enclosures . 20
A.1 Example 1 . 20
A.2 Example 2 . 23
Annex B (informative) Operating current and power losses of conductors . 27
Bibliography . 32
Figure 1 – Temperature-rise characteristic curve for enclosures with
A exceeding 1,25 m . 10
e
Figure 2 – Temperature-rise characteristic curve for enclosures with A
e
not exceeding 1,25 m . 10
Figure 3 – Enclosure constant k for enclosures without ventilation openings, with an
effective cooling surface A > 1,25 m . 13
e
Figure 4 – Temperature distribution factor c for enclosures without ventilation openings
and with an effective cooling surface A > 1,25 m . 14
e
Figure 5 – Enclosure constant k for enclosures with ventilation openings and an
effective cooling surface A > 1,25 m . 15
e
Figure 6 – Temperature distribution factor c for enclosures with ventilation openings
and an effective cooling surface A > 1,25 m . 16
e
Figure 7 – Enclosure constant k for enclosures without ventilation openings and with
an effective cooling surface A ≤ 1,25 m . 17
e
Figure 8 – Temperature distribution factor c for enclosures without ventilation openings
and with an effective cooling surface A ≤ 1,25 m . 18
e
Figure 9 – Calculation of temperature rise of air inside enclosures . 19
Figure A.1 – Example 1, calculation for an enclosure with exposed side faces without
ventilation openings and without internal horizontal partitions . 20
Figure A.2 – Example 1, calculation for a single enclosure . 22
Figure A.3 – Example 2, calculation for an enclosure for wall-mounting with ventilation
openings . 23
Figure A.4 – Example 2, calculation for one enclosure half . 24
Figure A.5 – Example 2, calculation for an enclosure for wall-mounting with ventilation
openings . 26
Table 1 – Method of calculation, application, formulae and characteristics . 11
Table 2 – Symbols, units and designations . 12
Table 3 – Surface factor b according to the type of installation . 12
Table 4 – Factor d for enclosures without ventilation openings and with an effective
cooling surface A >1,25 m . 12
e
Table 5 – Factor d for enclosures with ventilation openings and an effective cooling
surface A >1,25 m . 12
e
Table B.1 – Operating current and power loss of single-core copper cables with a
permissible conductor temperature of 70 °C (ambient temperature inside the
enclosure: 55 °C) . 28
Table B.2 – Reduction factor k for cables with a permissible conductor temperature
of 70 °C (extract from IEC 60364-5-52:2009, Table B.52-14) . 29
Table B.3 – Operating current and power loss of bare copper bars with rectangular
cross-section, run horizontally and arranged with their largest face vertical (ambient
temperature inside the enclosure: 55 °C, temperature of the conductor 70 °C) . 30
Table B.4 – Factor k for different temperatures of the air inside the enclosure and/or
for the conductors . 31
– 4 – IEC TR 60890:2014 © IEC 2014
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
A METHOD OF TEMPERATURE-RISE VERIFICATION OF LOW-VOLTAGE
SWITCHGEAR AND CONTROLGEAR ASSEMBLIES BY CALCULATION
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC pub
...
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