IEC 60364-4-44:2007
(Main)Low-voltage electrical installations - Part 4-44: Protection for safety - Protection against voltage disturbances and electromagnetic disturbances
Low-voltage electrical installations - Part 4-44: Protection for safety - Protection against voltage disturbances and electromagnetic disturbances
The rules of this Part of IEC 60364 are intended to provide requirements for the safety of electrical installations in the event of voltage disturbances and electromagnetic disturbances generated for different specified reasons. This second edition of IEC 60364-4-44 cancels and replaces the first edition published in 2001, amendment 1 (2003) and amendment 2 (2006). The contents of the corrigenda of May 2010 and October 2011 have been included in this copy.
Installations électriques à basse tension - Partie 4-44: Protection pour assurer la sécurité - Protection contre les perturbations de tension et les perturbations électromagnétiques
Les règles de la présente Partie de la CEI 60364 sont destinées à donner des exigences pour la sécurité des installations électriques en cas de perturbations de tension ou d'influences électromagnétiques dues à des raisons diverses. Cette deuxième édition de la CEI 60364-4-44 annule et remplace la première édition parue en 2001, l'amendement 1 (2003) et l'amendement 2 (2006). Le contenu des corrigendum de mai 2010 et octobre 2011 a été pris en considération dans cet exemplaire.
General Information
Relations
Buy Standard
Standards Content (Sample)
IEC 60364-4-44
Edition 2.0 2007-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Low-voltage electrical installations –
Part 4-44: Protection for safety – Protection against voltage disturbances and
electromagnetic disturbances
Installations électriques à basse tension –
Partie 4-44: Protection pour assurer la sécurité – Protection contre les
perturbations de tension et les perturbations électromagnétiques
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 la CEI ou du Comité national de la CEI du pays du demandeur.
Si vous avez des questions sur le copyright de la CEI ou si vous désirez obtenir des droits supplémentaires sur cette
publication, utilisez les coordonnées ci-après ou contactez le Comité national de la CEI de votre pays de résidence.
IEC Central Office
3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: inmail@iec.ch
Web: 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.
ƒ Catalogue of IEC publications: www.iec.ch/searchpub
The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…).
It also gives information on projects, withdrawn and replaced publications.
ƒ IEC Just Published: www.iec.ch/online_news/justpub
Stay up to date on all new IEC publications. Just Published details twice a month all new publications released. Available
on-line and also by email.
ƒ Electropedia: www.electropedia.org
The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions
in English and French, with equivalent terms in additional languages. Also known as the International Electrotechnical
Vocabulary online.
ƒ Customer Service Centre: www.iec.ch/webstore/custserv
If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service
Centre FAQ or contact us:
Email: csc@iec.ch
Tel.: +41 22 919 02 11
Fax: +41 22 919 03 00
A propos de la CEI
La Commission Electrotechnique Internationale (CEI) 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 CEI
Le contenu technique des publications de la CEI est constamment revu. Veuillez vous assurer que vous possédez
l’édition la plus récente, un corrigendum ou amendement peut avoir été publié.
ƒ Catalogue des publications de la CEI: www.iec.ch/searchpub/cur_fut-f.htm
Le Catalogue en-ligne de la CEI vous permet d’effectuer des recherches en utilisant différents critères (numéro de référence,
texte, comité d’études,…). Il donne aussi des informations sur les projets et les publications retirées ou remplacées.
ƒ Just Published CEI: www.iec.ch/online_news/justpub
Restez informé sur les nouvelles publications de la CEI. Just Published détaille deux fois par mois les nouvelles
publications parues. Disponible en-ligne et aussi par email.
ƒ Electropedia: www.electropedia.org
Le premier dictionnaire en ligne au monde de termes électroniques et électriques. Il contient plus de 20 000 termes et
définitions en anglais et en français, ainsi que les termes équivalents dans les langues additionnelles. Egalement appelé
Vocabulaire Electrotechnique International en ligne.
ƒ Service Clients: www.iec.ch/webstore/custserv/custserv_entry-f.htm
Si vous désirez nous donner des commentaires sur cette publication ou si vous avez des questions, visitez le FAQ du
Service clients ou contactez-nous:
Email: csc@iec.ch
Tél.: +41 22 919 02 11
Fax: +41 22 919 03 00
IEC 60364-4-44
Edition 2.0 2007-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Low-voltage electrical installations –
Part 4-44: Protection for safety – Protection against voltage disturbances and
electromagnetic disturbances
Installations électriques à basse tension –
Partie 4-44: Protection pour assurer la sécurité – Protection contre les
perturbations de tension et les perturbations électromagnétiques
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XA
CODE PRIX
ICS 91.140.50 ISBN 2-8318-9261-9
– 2 – 60364-4-44 © IEC:2007
CONTENTS
FOREWORD.5
INTRODUCTION.7
440.1 Scope .8
440.2 Normative references.8
441 (Vacant).9
442 Protection of low-voltage installations against temporary overvoltages due to earth
faults in the high-voltage system and due to faults in the low-voltage system .9
442.1 Scope and object .9
442.1.1 General.9
442.1.2 Symbols .10
442.2 Overvoltages in LV-systems during a high-voltage earth fault .11
442.2.1 Magnitude and duration of power frequency fault-voltage .12
442.2.2 Magnitude and duration of power frequency stress-voltages.13
442.2.3 Requirements for calculation of limits .14
442.3 Power frequency stress voltage in case of loss of the neutral conductor in a
TN and TT system .14
442.4 Power frequency stress voltage in the event of an earth fault in an IT system
with distributed neutral .14
442.5 Power frequency stress voltage in the event of short-circuit between a line
conductor and the neutral conductor .14
443 Protection against overvoltages of atmospheric origin or due to switching.14
443.1 General .14
443.2 Classification of impulse withstand voltages (overvoltage categories) .15
443.2.1 Purpose of classification of impulse withstand voltages
(overvoltage categories) .15
443.2.2 Relationship between impulse withstand voltages of equipment and
overvoltage categories .15
443.3 Arrangements for overvoltage control.16
443.3.1 Inherent overvoltage control .16
443.3.2 Protective overvoltage control.16
443.4 Required impulse withstand voltage of equipment.18
444 Measures against electromagnetic influences.18
444.1 General .18
444.2 (void) .19
444.3 Definitions .19
444.4 Mitigation of Electromagnetic Interference (EMI) .20
444.4.1 Sources of EMI.20
444.4.2 Measures to reduce EMI.21
444.4.3 TN-system .22
444.4.4 TT system .26
444.4.5 IT system .27
444.4.6 Multiple-source supply.28
444.4.7 Transfer of supply .31
444.4.8 Services entering a building.33
444.4.9 Separate buildings.34
444.4.10 Inside buildings .34
444.4.11 Protective devices .36
60364-4-44 © IEC:2007 – 3 –
444.4.12 Signal cables.36
444.5 Earthing and equipotential bonding.36
444.5.1 Interconnection of earth electrodes.36
444.5.2 Interconnection of incoming networks and earthing arrangements.37
444.5.3 Different structures for the network of equipotential conductors and
earthing conductors.37
444.5.4 Equipotential bonding networks in buildings with several floors .39
444.5.5 Functional earthing conductor.40
444.5.6 Commercial or industrial buildings containing significant amounts
of information technology equipment.41
444.5.7 Earthing arrangements and equipotential bonding of information
technology installations for functional purposes .41
444.6 Segregation of circuits .42
444.6.1 General.42
444.6.2 Design guidelines .42
444.6.3 Installation guidelines .43
444.7 Cable management systems .44
444.7.1 General.44
444.7.2 Design guidelines .44
444.7.3 Installation guidelines .45
445 Protection against undervoltage .47
445.1 General requirements .47
Annex A (informative) Explanatory notes concerning 442.1 and 442.2.48
Annex B (informative) Guidance for overvoltage control by SPDs applied to overhead
lines.50
Annex C (normative) Determination of the conventional length, d .52
Bibliography .54
Figure 44.A1 – Representative schematic sketch for possible connections to earth in
substation and LV-Installation and occurring overvoltages in case of faults .11
Figure 44.A2 – Tolerable fault-voltage due to an earth-fault in the HV system .13
Figure 44.R1 − By-pass conductor for screen reinforcement to provide a common
equipotential bonding system .21
Figure 44.R2 − Example of a substitute or by-pass equipotential bonding conductor in a
TT-system.22
Figure 44.R3A − Avoidance of neutral conductor currents in a bonded structure by
using the TN-S system from the origin of the public supply up to and including the final
circuit within a building .23
Figure 44.R3B − Avoidance of neutral conductor currents in a bonded structure by using
a TN-S system downstream of a consumer’s private supply transformer .24
Figure 44.R4 − TN-C
...
IEC 60364-4-44 ®
Edition 2.1 2015-09
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage electrical installations –
Part 4-44: Protection for safety – Protection against voltage disturbances and
electromagnetic disturbances
Installations électriques à basse tension –
Partie 4-44: Protection pour assurer la sécurité – Protection contre les
perturbations de tension et les perturbations électromagnétiques
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 15
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 60 000 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
15 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
La recherche avancée permet de trouver des publications IEC Plus de 60 000 entrées terminologiques électrotechniques, en
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 60364-4-44 ®
Edition 2.1 2015-09
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage electrical installations –
Part 4-44: Protection for safety – Protection against voltage disturbances and
electromagnetic disturbances
Installations électriques à basse tension –
Partie 4-44: Protection pour assurer la sécurité – Protection contre les
perturbations de tension et les perturbations électromagnétiques
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.100.10; 33.100.20; 91.140.50 ISBN 978-2-8322-2916-3
IEC 60364-4-44 ®
Edition 2.1 2015-09
CONSOLIDATED VERSION
REDLINE VERSION
VERSION REDLINE
colour
inside
Low-voltage electrical installations –
Part 4-44: Protection for safety – Protection against voltage disturbances and
electromagnetic disturbances
Installations électriques à basse tension –
Partie 4-44: Protection pour assurer la sécurité – Protection contre les
perturbations de tension et les perturbations électromagnétiques
– 2 – IEC 60364-4-44:2007+AMD1:2015 CSV
© IEC 2015
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
440.1 Scope . 8
440.2 Normative references . 8
441 (Vacant) . 9
442 Protection of low-voltage installations against temporary overvoltages due to earth
faults in the high-voltage system and due to faults in the low-voltage system . 9
442.1 Field of application . 9
442.1.1 General requirements . 10
442.1.2 Symbols . 10
442.2 Overvoltages in LV-systems during a high-voltage earth fault . 11
442.2.1 Magnitude and duration of power-frequency fault voltage . 12
442.2.2 Magnitude and duration of power-frequency stress voltages . 13
442.2.3 Requirements for calculation of limits . 14
442.3 Power-frequency stress voltage in case of loss of the neutral conductor in a
TN and TT system . 14
442.4 Power-frequency stress voltage in the event of an earth fault in an IT
system with distributed neutral . 14
442.5 Power-frequency stress voltage in the event of a short-circuit between a line
conductor and the neutral conductor . 15
443 Protection against transient overvoltages of atmospheric origin or due to switching . 15
443.1 General . 15
443.2 Classification of impulse withstand voltages (overvoltage categories) .
443.2.1 Purpose of classification of impulse withstand voltages
(overvoltage categories) .
443.2 Void . 16
443.3 Arrangements for overvoltage control .
443.3.1 Inherent overvoltage control .
443.3.2 Protective overvoltage control .
443.3 Terms and definitions . 16
443.4 Required impulse withstand voltage of equipment.
443.4 Overvoltage control . 17
443.5 Risk assessment method . 17
443.6 Classification of rated impulse voltages (overvoltage categories) . 19
443.6.1 Purpose of classification of rated impulse voltages (overvoltage
categories) . 19
443.26.2 Relationship between impulse withstand Rated impulse voltages of
equipment and overvoltage categories . 20
444 Measures against electromagnetic influences . 23
444.1 General . 23
444.2 (void) . 24
444.3 Definitions . 24
444.4 Mitigation of electromagnetic interference (EMI) . 25
444.4.1 Sources of EMI. 25
444.4.2 Measures to reduce EMI . 25
444.4.3 TN-system . 27
444.4.4 TT system . 31
© IEC 2015
444.4.5 IT system . 32
444.4.6 Multiple-source supply . 33
444.4.7 Transfer of supply . 36
444.4.8 Services entering a build ing . 38
444.4.9 Separate buildings . 39
444.4.10 Inside buildings . 39
444.4.11 Protective devices . 41
444.4.12 Signal cables . 41
444.5 Earthing and equipotential bonding . 41
444.5.1 Interconnection of earth electrodes . 41
444.5.2 Interconnection of incoming networks and earthing arrangements . 42
444.5.3 Different structures for the network of equipotential conductors and
earthing conductors . 42
444.5.4 Equipotential bonding networks in buildings with several floors . 44
444.5.5 Functional earthing conductor . 45
444.5.6 Commercial or industrial buildings containing significant amounts
of information technology equipm ent. 46
444.5.7 Earthing arrangements and equipotential bonding of information
technology installations for functional purposes . 46
444.6 Segreg
...
IEC 60364-4-44 ®
Edition 2.2 2018-01
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage electrical installations –
Part 4-44: Protection for safety – Protection against voltage disturbances and
electromagnetic disturbances
Installations électriques à basse tension –
Partie 4-44: Protection pour assurer la sécurité – Protection contre les
perturbations de tension et les perturbations électromagnétiques
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 info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
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 21 000 terms and definitions in
Technical Specifications, Technical Reports and other English and French, with equivalent terms in 16 additional
documents. Available for PC, Mac OS, Android Tablets and languages. Also known as the International Electrotechnical
iPad. Vocabulary (IEV) online.
IEC publications search - webstore.iec.ch/advsearchform IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a 67 000 electrotechnical terminology entries in English and
variety of criteria (reference number, text, technical French extracted from the Terms and Definitions clause of
committee,…). It also gives information on projects, replaced IEC publications issued since 2002. Some entries have been
and withdrawn publications. 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: sales@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 21 000 termes et définitions en anglais
Spécifications techniques, Rapports techniques et autres
et en français, ainsi que les termes équivalents dans 16
documents de l'IEC. Disponible pour PC, Mac OS, tablettes
langues additionnelles. Egalement appelé Vocabulaire
Android et iPad.
Electrotechnique International (IEV) en ligne.
Recherche de publications IEC -
Glossaire IEC - std.iec.ch/glossary
webstore.iec.ch/advsearchform
67 000 entrées terminologiques électrotechniques, en anglais
La recherche avancée permet de trouver des publications IEC et en français, extraites des articles Termes et Définitions des
en utilisant différents critères (numéro de référence, texte, publications IEC parues depuis 2002. Plus certaines entrées
comité d’études,…). Elle donne aussi des informations sur les antérieures extraites des publications des CE 37, 77, 86 et
projets et les publications remplacées ou retirées. 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 Si vous désirez nous donner des commentaires sur cette
Published détaille les nouvelles publications parues. publication ou si vous avez des questions contactez-nous:
Disponible en ligne et aussi une fois par mois par email. sales@iec.ch.
IEC 60364-4-44 ®
Edition 2.2 2018-01
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage electrical installations –
Part 4-44: Protection for safety – Protection against voltage disturbances and
electromagnetic disturbances
Installations électriques à basse tension –
Partie 4-44: Protection pour assurer la sécurité – Protection contre les
perturbations de tension et les perturbations électromagnétiques
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.100.10; 33.100.20; 91.140.50 ISBN 978-2-8322-5286-4
IEC 60364-4-44 ®
Edition 2.2 2018-01
CONSOLIDATED VERSION
REDLINE VERSION
VERSION REDLINE
colour
inside
Low-voltage electrical installations –
Part 4-44: Protection for safety – Protection against voltage disturbances and
electromagnetic disturbances
Installations électriques à basse tension –
Partie 4-44: Protection pour assurer la sécurité – Protection contre les
perturbations de tension et les perturbations électromagnétiques
– 2 – IEC 60364-4-44:2007+AMD1:2015
+AMD2:2018 CSV © IEC 2018
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
440.1 Scope . 8
440.2 Normative references . 8
441 (Vacant) . 10
442 Protection of low-voltage installations against temporary overvoltages due to earth
faults in the high-voltage system and due to faults in the low-voltage system . 10
442.1 Field of application . 10
442.1.1 General requirements . 10
442.1.2 Symbols . 10
442.2 Overvoltages in LV-systems during a high-voltage earth fault . 11
442.2.1 Magnitude and duration of power-frequency fault voltage . 13
442.2.2 Magnitude and duration of power-frequency stress voltages . 14
442.2.3 Requirements for calculation of limits . 15
442.3 Power-frequency stress voltage in case of loss of the neutral conductor
in a TN and TT system . 15
442.4 Power-frequency stress voltage in the event of an earth fault in an IT
system with distributed neutral . 15
442.5 Power-frequency stress voltage in the event of a short-circuit between
a line conductor and the neutral conductor . 16
443 Protection against transient overvoltages of atmospheric origin or due to switching . 16
443.1 General . 16
443.2 Void . 17
443.3 Terms and definitions . 17
443.4 Overvoltage control . 18
443.5 Risk assessment method . 18
443.26 Classification of rated impulse voltages (overvoltage categories) . 20
443.26.1 Purpose of classification of rated impulse voltages (overvoltage
categories) . 20
443.26.2 Relationship between impulse withstand Rated impulse voltages of
equipment and overvoltage categories . 21
443.3 Arrangements for overvoltage control .
443.3.1 Inherent overvoltage control .
443.3.2 Protective overvoltage control .
443.4 Required impulse withstand voltage of equipment.
444 Measures against electromagnetic influences . 24
444.1 General . 24
444.2 (void) . 25
444.3 Definitions . 25
444.4 Mitigation of electromagnetic interference (EMI) . 26
444.4.1 Sources of EMI . 26
444.4.2 Measures to reduce EMI . 26
444.4.3 TN-system . 28
444.4.4 TT system . 32
444.4.5 IT system . 33
444.4.6 Multiple-source supply . 34
444.4.7 Transfer of supply . 37
+AMD2:2018 CSV © IEC 2018
444.4.8 Services entering a building . 39
444.4.9 Separate buildings . 40
444.4.10 Inside buildings . 40
444.4.11 Protective devices . 42
444.4.12 Signal cables . 42
444.5 Earthing and equipotential bonding . 42
444.5.1 Interconnection of earth electrodes . 42
444.5.2 Interconnection of incoming networks and earthing arrangements . 43
444.5.3 Different structures for the network of equipotential conductors and
earthing conductors . 43
444.5.4 Equipotential bonding networks in buildings with several floors . 45
444.5.5 Functional earthing conductor . 46
444.5.6 Commercial or industrial buildings containing significant amounts
of information technology equipment . 47
444.5.7 Earthing arrangements and equipotential bonding of information
technology installations for functional purposes . 47
444.6 Segregation of circuits . 48
444.6.1 General .
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.