IEC 60364-4-44
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.
Električne inštalacije zgradb - 4-44. del: Zaščitni ukrepi - Zaščita pred prenapetostmi - Zaščita pred napetostnimi in elektromagnetnimi motnjami
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SLOVENSKI STANDARD
SIST IEC 60364-4-44:2009
01-april-2009
1DGRPHãþD
SIST IEC 60364-4-44:2006
(OHNWULþQHLQãWDODFLMH]JUDGEGHO =DãþLWQLXNUHSL=DãþLWDSUHG
SUHQDSHWRVWPL=DãþLWDSUHGQDSHWRVWQLPLLQHOHNWURPDJQHWQLPLPRWQMDPL
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
Ta slovenski standard je istoveten z: IEC 60364-4-44
ICS:
29.120.50 9DURYDONHLQGUXJD Fuses and other overcurrent
PHGWRNRYQD]DãþLWD protection devices
91.140.50 Sistemi za oskrbo z elektriko Electricity supply systems
SIST IEC 60364-4-44:2009 en,fr
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
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
---------------------- Page: 2 ----------------------
– 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
9
faults in the high-voltage system and due to faults in the low-voltage system .
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
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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-S system within an existing building installation .25
Figure 44.R5 – TT system within a building installation .26
Figure 44.R6 – IT system within a building installation .27
Figure 44.R7A – TN multiple-source power supply with a non-suitable multiple
connection between PEN and earth .28
Figure 44.R7B – TN multiple source power supplies to an installation with connection to
earth of the star points at one and the same point .29
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– 4 – 60364-4-44 © IEC:2007
Figure 44.R8 – TT multiple-source power supplies to an installation with connection to
earth of the star points at one and the same point .30
Figure 44.R9A − Three-phase alternative power supply with a 4-pole switch .31
Figure 44.R9B – Neutral current flow in a three-phase alternative power supply with an
unsuitable 3-pole switch .32
Figure 44.R9C − Single-phase alternative power supply with 2-pole switch.33
Figure 44.R10 − Armoured cables and metal pipes entering the buildings (examples) .34
Figure 44.R11 − Illustration of measures in an existing building .35
Figure 44.R12 – Interconnected earth electrodes.36
Figure 44.R13 – Examples of protective conductors in star network .37
Figure 44.R14 – Example of multiple meshed bonding star network .38
Figure 44.R15 – Example of a common meshed bonding star network .39
Figure 44.R16 – Example of equipotential bonding networks in structures without
lightning protection systems .40
Figure 44.R17A − Separation between power and information technology cables for
cable route lengths ≤ 35 m .43
Figure 44.R17B − Separation between power and information technology cables for
cable route lengths > 35 m .43
Figure 44.R18 – Separation of cables in wiring systems.44
Figure 44.R19 – Cable arrangements in metal cable-trays .45
Figure 44.R20 – Continuity of metallic system components .46
Figure 44.R21 – Location of cables inside metallic construction elements .46
Figure 44.R22 – Connection of metallic sections.47
Figure 44.Q – Examples of how to apply d , d and d for the determination of d .53
1 2 3
Table 44.A1 – Power frequency stress voltages and power frequency fault voltage in the
low voltage system .12
Table 44.A2 – Permissible power frequency stress-voltage.13
Table 44.B – Required rated impulse withstand voltage of equipment .18
Table B.1 – Different possibilities for IT systems.51
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60364-4-44 © IEC:2007 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_______________
LOW-VOLTAGE ELECTRICAL INSTALLATIONS –
Part 4-44: Protection for safety –
Protection against voltage disturbances and
electromagnetic disturbances
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,
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Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
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with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60364-4-44 has been prepared by IEC technical committee 64:
Electrical installations and protection against electric shock.
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 document 64/1600/FDIS, circulated to the National Committees as Amendment 3, led to
the publication of the new edition.
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– 6 – 60364-4-44 © IEC:2007
The text of this standard is based on the first edition, its Amendment 1, Amendment 2 and the
following documents:
FDIS Report on voting
64/1600/FDIS 64/1609/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all the parts in the IEC 60364 series, under the general title Low-voltage electrical
installations, can be found on the IEC website.
Future standards in this series will carry the new general title as cited above. Titles of existing
standards in this series will be updated at the time of the next edition.
The committee has decided that the contents of this publication will remain unchanged until the
maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
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60364-4-44 © IEC:2007 – 7 –
INTRODUCTION
Part 4-44 of IEC 60364 covers the protection of electrical installations and measures against
voltage disturbances and electromagnetic disturbances.
The requirements are arranged into four clauses as follows:
Clause 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
Clause 443 Protection against overvoltages of atmospheric origin or due to switching
Clause 444 Measures against electromagnetic influences
Clause 445 Protection against undervoltage
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LOW-VOLTAGE ELECTRICAL INSTALLATIONS –
Part 4-44: Protection for safety –
Protection against voltage disturbances and
electromagnetic disturbances
440.1 Scope
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.
The rules of this part are not intended to apply to systems for distribution of energy to the
public, or power generation and transmission for such systems (see the scope of IEC 60364-1)
although such disturbances may be conducted into or between electrical installations via these
supply systems.
440.2 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.
IEC 60038:1983, IEC standard voltages
IEC 60050-604:1987, International Electrotechnical Vocabulary – Chapter 604: Generation,
transmission and distribution of electricity – Operation
IEC 60364-1, Low-voltage electrical installations – Part 1: Fundamental principles, assessment
of general characteristics, definitions
IEC 60364-4-41:2005, Electrical installations of buildings – Part 4-41: Protection for safety –
Protection against electric shock
IEC 60364-5-54:2002, Electrical installations of buildings − Part 5-54: Selection and erection of
1
electrical equipment – Earthing arrangements and protective bonding conductors
IEC 60479-1:2005, Effects of current on human beings and livestock – Part 1: General aspects
IEC 60664-1:2007, Insulation co-ordination for equipment within low-voltage systems – Part 1:
Principles, requirements and tests
IEC 60950-1, Information technology equipment – Safety – Part 1: General requirements
IEC 61000-2-5:1995, Electromagnetic compatibility (EMC) − Part 2: Environment − Section 5:
Classification of electromagnetic environments – Basic EMC publication
IEC 61000-6-1, Electromagnetic compatibility (EMC) – Part 6-1: Generic standards – Immunity
for residential, commercial and light-industrial environments
IEC 61000-6-2, Electromagnetic compatibility (EMC) – Part 6-2: Generic standards – Immunity
for industrial environments
___________
1
A third edition is currently in preparation.
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60364-4-44 © IEC:2007 – 9 –
IEC 61000-6-3, Electromagnetic compatibility (EMC) – Part 6-3: Generic standards – Emission
standard for residential, commercial and light-industrial environments
IEC 61000-6-4, Electromagnetic compatibility (EMC) – Part 6-4: Generic standards – Emission
standard for industrial environments
IEC 61558-2-1, Safety of power transformers, power supplies, reactors and similar products –
Part 2-1: Particular requirements for tests for separating transformers and power supplies
incorporating separating transformers for general applications
IEC 61558-2-4, Safety of power transformers, power supply units and similar – Part 2-4:
Particular requirements for isolating transformers for general use
IEC 61558-2-6, Safety of power transformers, power supply units and similar – Part 2-6:
Particular requirements for safety isolating transformers for general use
IEC 61558-2-15, Safety of power transformers, power supply units and similar – Part 2-15:
Particular requirements for isolating transformers for the supply of medical locations
IEC 61643 (all parts), Low-voltage surge protective devices
IEC 61936-1, Power installations exceeding 1 kV a.c. – Part 1: Common rules
IEC 62305-1, Protection against lightning – Part 1: General principles
IEC 62305-3, Protection against lightning – Part 3: Physical damage to structures and life
hazard
IEC 62305-4, Protection against lightning – Part 4: Electrical and electronic systems within
structures
441 (Vacant)
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
442.1 Field of application
The rules of this clause provide requirements for the safety of low-voltage installation in the
event of
– a fault between the high-voltage system and earth in the transformer substation that
supplies the low-voltage installation,
– a loss of the supply neutral in the low-voltage system,
– a short-circuit between a line conductor and neutral,
– an accidental earthing of a line conductor of a low-voltage IT-system.
The requirements for the earthing arrangement at the transformer substation are given in
IEC 61936-1.
442.1.1 General requirements
As Clause 442 covers faults between a high-voltage line and the earth in the HV/LV substation,
it gives rules for the designer and installer of the substation. It is necessary to have the
following information concerning the high-voltage system:
– quality of the system earthing;
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– 10 – 60364-4-44 © IEC:2007
– maximum level of earth fault current;
– resistance of the earthing arrangement.
The following subclauses consider four situations as proposed in 442.1, which generally cause
the most severe temporary overvoltages such as defined in IEC 60050-604:
– fault between the high-voltage system(s) and earth (see 442.2);
– loss of the neutral in a low-voltage system (see 442.3);
– accidental earthing of a low-voltage IT system (see 442.4);
– short-circuit in the low-voltage installation (see 442.5).
442.1.2 Symbols
In Clause 442 the following symbols are used (see Figure 44.A1):
I part of the earth fault current in the high-voltage system that flows through the earthing
E
arrangement of the transformer substation.
resistance of the earthing arrangement of the transformer substation.
R
E
R resistance of the earthing arrangement of the exposed-conductive-parts of the
A
equipment of the low-voltage installation.
R resistance of the earthing arrangement of the low-voltage system neutral, for low-
B
voltage systems in which the earthing arrangements of the transformer substation and
of the low-voltage system neutral are electrically independent.
U in TN- and TT-systems: nominal a.c. r.m.s. line voltage to earth
o
in IT-systems: nominal a.c. voltage between line conductor and neutral conductor or
mid point conductor, as appropriate
U power-frequency fault voltage that appears in the low-voltage system between exposed-
f
conductive-parts and earth for the duration of the fault.
power-frequency stress voltage between the line conductor and the exposed-
U
1
conductive-parts of the low-voltage equipment of the transformer substation during the
fault.
U power-frequency stress voltage between the line conductor and the exposed-
2
conductive-parts of the low-voltage equipment of the low-voltage installation during the
fault.
NOTE 1 The power-frequency stress voltage (U and U ) is the voltage that appears across the insulation of low-
1 2
voltage equipment and across surge protective devices connected to the low-voltage system.
The following additional symbols are used in respect of IT-systems in which the exposed-
conductive-parts of the equipment of the low-voltage installation are connected to an earthing
arrangement that is electrically independent of the earthing arrangement of the transformer
substation.
I fault current that flows through the earthing arrangement of the exposed-conductive-
h
parts of the equipment of the low-voltage installation during a period when there is a
high-voltage fault and a first fault in the low-voltage installation (see Table 44.A1).
I fault current, in accordance with 411.6.2, that flows through the earthing arrangement
d
of the exposed-conductive-parts of the low-voltage installation during the first fault in a
low-voltage system (see Table 44.A1).
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60364-4-44 © IEC:2007 – 11 –
Z impedance (e.g. IMD internal impedance, artificial neutral impedance) between the low-
voltage system and an earthing arrangement.
NOTE 2 An earthing arrangement may be considered electrically independent of another earthing arrangement if a
rise of potential with respect to earth in one earthing arrangement does not cause an unacceptable rise of potential
with respect to earth in the other earthing arrangement. See IEC 61936-1.
442.2 Overvoltages in LV-systems during a high-voltage earth fault
In case of a fault to earth on the HV-side of the substation, the following types of overvoltage
may affect the LV-installation:
• power frequency fault-voltage (U );
f
• power frequency stress-voltages (U and U ).
1 2
Table 44.A1 provides the relevant methods of calculation for the different types of
overvoltages.
NOTE 1 Table 44.A1 deals with IT systems with a neutral point only. For IT systems with no neutral point, the
formulae should be adjusted accordingly.
Substation
U LV Installation
1
U
2
HV LV
L1
L2
L3
or N or PEN
Z
I R R R U
E E B A f
IEC 1379/07
Figure 44.A1 – Representative schematic sketch for possible connections to earth
i
...
SLOVENSKI SIST IEC 60364-4-44:2006
STANDARD
september 2006
Električne inštalacije zgradb – 4-44. del: Zaščitni ukrepi – Zaščita pred
prenapetostmi – Zaščita pred napetostnimi motnjami in pred
elektromagnetnimi motnjami
Electrical installations of buildings - Part 4-44: Protection for safety - Protection
against voltag
...
SLOVENSKI STANDARD
SIST IEC 60364-4-44:2009
01-april-2009
1DGRPHãþD
SIST IEC 60364-4-44:2006
(OHNWULþQHLQãWDODFLMH]JUDGEGHO =DãþLWQLXNUHSL=DãþLWDSUHG
SUHQDSHWRVWPL=DãþLWDSUHGQDSHWRVWQLPLLQHOHNWURPDJQHWQLPLPRWQMDPL
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
Ta slovenski standard je istoveten z: IEC 60364-4-44
ICS:
29.120.50 9DURYDONHLQGUXJD Fuses and other overcurrent
PHGWRNRYQD]DãþLWD protection devices
91.140.50 Sistemi za oskrbo z elektriko Electricity supply systems
SIST IEC 60364-4-44:2009 en,fr
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST IEC 60364-4-44:2009
---------------------- Page: 2 ----------------------
SIST IEC 60364-4-44:2009
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
---------------------- Page: 3 ----------------------
SIST IEC 60364-4-44:2009
– 56 – 60364-4-44 © CEI:2007
SOMMAIRE
AVANT-PROPOS.59
INTRODUCTION.61
440.1 Domaine d'application et objet .62
440.2 Références normatives .62
441 (Disponible) .63
442 Protection des installations électriques à basse tension contre les surtensions
temporaires dues à des défauts à la terre dans le réseau haute tension et dues à
des défauts dans le réseau basse tension .63
442.1 Domaine d’application .63
442.1.1 Généralités .63
442.1.2 Symboles .64
442.2 Surtensions dans un réseau BT en cas de défaut HT.65
442.2.1 Valeur et durée de la tension de défaut à fréquence industrielle .66
442.2.2 Valeur et durée des contraintes à fréquence industrielle .67
442.2.3 Exigences pour le calcul des limites.68
442.3 Contraintes de tension en cas de rupture du conducteur neutre en
schémas TN et en schéma TT .68
442.4 Contraintes de tension en cas de défaut à la terre en schéma IT avec
neutre distribué .68
442.5 Contraintes de tension en cas de court-circuit entre phase et neutre .69
443 Protection contre les surtensions d’origine atmosphérique ou dues à des
manœuvres .69
443.1 Généralités.69
443.2 Classification des tensions de tenue aux chocs (catégories de surtensions) .70
443.2.1 Objet de la classification des tensions de tenue aux chocs
(catégories de surtensions).70
443.2.2 Relation entre tensions de tenue aux chocs des matériels et
catégories de surtensions .70
443.3 Dispositions pour la maîtrise des surtensions .71
443.3.1 Situation naturelle des surtensions .71
443.3.2 Situation contrôlée des surtensions.71
443.4 Tensions de tenue aux chocs prescrites pour les matériels.72
444 Dispositions contre les influences électromagnétiques.73
444.1 Généralités.73
444.2 (disponible).73
444.3 Définitions .74
444.4 Mesures d’atténuation des influences électromagnétiques.75
444.4.1 Sources des influences électromagnétiques.75
444.4.2 Dispositions de réduction des perturbations électromagnétiques.75
444.4.3 Schéma TN .77
444.4.4 Schéma TT .81
444.4.5 Schéma IT .82
444.4.6 Alimentation par plusieurs sources.83
444.4.7 Commutation de l’alimentation .86
444.4.8 Pénétration des services dans un bâtiment .89
444.4.9 Bâtiments séparés .89
444.4.10 Installations dans les bâtiments .89
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SIST IEC 60364-4-44:2009
60364-4-44 © CEI:2007 – 57 –
444.4.11 Dispositifs de protection.92
444.4.12 Câbles de communication .92
444.5 Mise à la terre et liaisons équipotentielles .92
444.5.1 Interconnexion des prises de terre .92
444.5.2 Interconnexion des réseaux entrants et mise à la terre .93
444.5.3 Différentes structures du réseau des conducteurs
d'équipotentialité et de mise à la terre.93
444.5.4 Réseau de terre dans des bâtiments à plusieurs étages.95
444.5.5 Conducteurs d'équipotentialité fonctionnelle .96
444.5.6 Bâtiments tertiaires ou industriels avec une installation importante
de matériels de traitement de l'information.97
444.5.7 Dispositions de mise à la terre et équipotentialités fonctionnelles
des matériels de traitement de l’information pour des raisons
fonctionnelles.97
444.6 Séparation des circuits .98
444.6.1 Généralités .98
444.6.2 Conception .98
444.6.3 Règles de mise en œuvre .99
444.7 Mise en œuvre des canalisations.100
444.7.1 Généralités .100
444.7.2 Guide de conception .100
444.7.3 Règles d’installation.101
445 Protection contre les baisses de tension .103
445.1 Exigences générales .103
Annexe A (informative) Notes explicatives relatives à 442.1 et 442.2. 104
Annexe B (informative) Guide pour l'application d'une situation contrôlée des
surtensions par des parafoudres dans les lignes aériennes .106
Annexe C (normative) Détermination de la longueur conventionnelle, d .108
Bibliographie.110
Figure 44.A1 – Schéma représentatif des diverses liaisons à la terre dans le poste de
transformation et dans l’installation BT et des surtensions afférentes en cas de défaut.65
Figure 44.A2 – Tension de défaut acceptable due à un défaut en HT.67
Figure 44.R1 – Conducteur d’accompagnement de renfort d’écran pour assurer un
réseau commun d’équipotentialité.76
Figure 44.R2 – Exemple de conducteur d’accompagnement ou de substitution en
schéma TT.76
Figure 44.R3A − Elimination des courants de conducteur neutre dans une structure
alimentée en schéma TN-S depuis l’origine du réseau public jusques et y compris les
circuits terminaux à l’intérieur du bâtiment .78
Figure 44.R3B − Elimination des courants de conducteur neutre dans une structure
alimentée en schéma TN-S en aval du transformateur d’alimentation privé du
consommateur .79
Figure 44.R4 – Schéma TN-C-S dans un bâtiment existant.80
Figure 44.R5 – Schéma TT dans un bâtiment .81
Figure 44.R6 – Schéma IT dans un bâtiment .82
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Figure 44.R7A – Schéma TN alimenté par plusieurs sources avec connexion multiple
non appropriée entre le PEN et la terre.83
Figure 44.R7B – Schéma TN alimenté par plusieurs sources avec points étoiles
connectés à un seul et même point de terre.84
Figure 44.R8 – Schéma TT alimenté par plusieurs sources avec points étoiles
connectés à un seul et même point de terre.85
Figure 44.R9A – Alimentation triphasée avec commutateur à 4 pôles .86
Figure 44.R9B – Ecoulement de courant dans le conducteur neutre dans une
alimentation triphasée avec commutateur à 3 pôles non approprié.87
Figure 44.R9C – Alimentation monophasée avec commutateur à 2 pôles.88
Figure 44.R10 – Exemple de pénétration de câbles armés et de canalisations
métalliques dans un bâtiment .89
Figure 44.R11 − Illustration des mesures décrites par le présent article dans un
bâtiment existant .91
Figure 44.R12 – Prises de terre interconnectées.92
Figure 44.R13 – Exemples de conducteurs de protection en étoile.93
Figure 44.R14 – Exemple de réseau à mailles multiples en étoile .94
Figure 44.R15 – Exemple de réseau en étoile à maillage commun.95
Figure 44.R16 – Exemple de réseau équipotentiel dans des structures sans systèmes
de protection contre la foudre .96
Figure 44.R17A – Distances de séparation entre circuits de puissance et de
communication pour des longueurs de câbles ≤ 35 m .99
Figure 44.R17B – Distances de séparation entre circuits de puissance et de
communication pour des longueurs de câbles > 35 m .99
Figure 44.R18 – Séparation des câbles d’une canalisation . 100
Figure 44.R19 – Disposition de câbles dans un chemin de câbles métallique.101
Figure 44.R20 – Exemple de réalisation de la continuité de supports métalliques .102
Figure 44.R21 – Emplacement des câbles dans des éléments de construction
102
métallique .
Figure 44.R22 – Interruption de sections métalliques.103
Figure 44.Q – Exemples d’utilisation de d , d et d pour la détermination de d .109
1 2 3
Tableau 44.A1 – Contraintes de tension et tensions de défaut industrielles dans le
réseau BT.66
Tableau 44.A2 – Contraintes à fréquence industrielle admissibles .68
Tableau 44.B – Tension assignée de tenue aux chocs prescrite pour les matériels.73
Tableau B.1 – Différentes possibilités de schéma IT . 107
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COMMISSION ÉLECTROTECHNIQUE INTERNATIONALE
______________
INSTALLATIONS ÉLECTRIQUES À BASSE TENSION –
Partie 4-44: Protection pour assurer la sécurité –
Protection contre les perturbations de tension
et les perturbations électromagnétiques
AVANT-PROPOS
1) La Commission Electrotechnique Internationale (CEI) est une organisation mondiale de normalisation
composée de l'ensemble des comités électrotechniques nationaux (Comités nationaux de la CEI). La CEI a
pour objet de favoriser la coopération internationale pour toutes les questions de normalisation dans les
domaines de l'électricité et de l'électronique. A cet effet, la CEI – entre autres activités – publie des Normes
internationales, des Spécifications techniques, des Rapports techniques, des Spécifications accessibles au
public (PAS) et des Guides (ci-après dénommés "Publication(s) de la CEI"). Leur élaboration est confiée à des
comités d'études, aux travaux desquels tout Comité national intéressé par le sujet traité peut participer. Les
organisations internationales, gouvernementales et non gouvernementales, en liaison avec la CEI, participent
également aux travaux. La CEI collabore étroitement avec l'Organisation Internationale de Normalisation (ISO),
selon des conditions fixées par accord entre les deux organisations.
2) Les décisions ou accords officiels de la CEI concernant les questions techniques représentent, dans la mesure
du possible, un accord international sur les sujets étudiés, étant donné que les Comités nationaux de la CEI
intéressés sont représentés dans chaque comité d’études.
3) Les Publications de la CEI se présentent sous la forme de recommandations internationales et sont agréées
comme telles par les Comités nationaux de la CEI. Tous les efforts raisonnables sont entrepris afin que la CEI
s'assure de l'exactitude du contenu technique de ses publications; la CEI ne peut pas être tenue responsable
de l'éventuelle mauvaise utilisation ou interprétation qui en est faite par un quelconque utilisateur final.
4) Dans le but d'encourager l'uniformité internationale, les Comités nationaux de la CEI s'engagent, dans toute la
mesure possible, à appliquer de façon transparente les Publications de la CEI dans leurs publications
nationales et régionales. Toutes divergences entre toutes Publications de la CEI et toutes publications
nationales ou régionales correspondantes doivent être indiquées en termes clairs dans ces dernières.
5) La CEI n’a prévu aucune procédure de marquage valant indication d’approbation et n'engage pas sa
responsabilité pour les équipements déclarés conformes à une de ses Publications.
6) Tous les utilisateurs doivent s'assurer qu'ils sont en possession de la dernière édition de cette publication.
7) Aucune responsabilité ne doit être imputée à la CEI, à ses administrateurs, employés, auxiliaires ou
mandataires, y compris ses experts particuliers et les membres de ses comités d'études et des Comités
nationaux de la CEI, pour tout préjudice causé en cas de dommages corporels et matériels, ou de tout autre
dommage de quelque nature que ce soit, directe ou indirecte, ou pour supporter les coûts (y compris les frais
de justice) et les dépenses découlant de la publication ou de l'utilisation de cette Publication de la CEI ou de
toute autre Publication de la CEI, ou au crédit qui lui est accordé.
8) L'attention est attirée sur les références normatives citées dans cette publication. L'utilisation de publications
référencées est obligatoire pour une application correcte de la présente publication.
9) L’attention est attirée sur le fait que certains des éléments de la présente Publication de la CEI peuvent faire
l’objet de droits de propriété intellectuelle ou de droits analogues. La CEI ne saurait être tenue pour
responsable de ne pas avoir identifié de tels droits de propriété et de ne pas avoir signalé leur existence.
La Norme internationale CEI 60364-4-44 a été établie par le comité d’études 64 de la CEI:
Installations électriques et protection contre les chocs électriques.
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 document 64/1600/FDIS, circulé comme Amendement 3 auprès des Comités nationaux de
la CEI, a conduit à la publication de la nouvelle édition.
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Le texte de cette norme est basé sur la première édition, son Amendement 1, son
Amendement 2 et sur les documents suivants:
FDIS Rapport de vote
64/1600/FDIS 64/1609/RVD
Le rapport de vote indiqué dans le tableau ci-dessus donne toute information sur le vote ayant
abouti à l'approbation de cette norme.
Cette publication a été rédigée selon les Directives ISO/CEI, Partie 2.
Une liste de toutes les parties de la série CEI 60364, présentées sous le titre général
Installations éléctriques à basse tension, peut être consultée sur le site web de la CEI.
Les normes futures de cette série porteront dorénavant le nouveau titre général cité ci-
dessus. Le titre des normes existant déjà sera mis à jour lors d’une prochaine édition.
Le comité a décidé que le contenu de cette publication ne sera pas modifié avant la date de
maintenance indiquée sur le site web de la CEI sous «http://webstore.iec.ch» dans les
données relatives à la publication recherchée. A cette date, la publication sera
• reconduite;
• supprimée;
• remplacée par une édition révisée, ou
• amendée.
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INTRODUCTION
La Partie 4-44 de la CEI 60364 traite de la protection des installations électriques et des
dispositions contre les perturbations de tension et les interférences électromagnétiques.
Les exigences sont traitées dans les quatre articles suivants:
Article 442: Protection des installations électriques à basse tension contre les surtensions
temporaires dues à des défauts à la terre dans le réseau haute tension et dues
à des défauts dans le réseau basse tension;
Article 443: Protection contre les surtensions d’origine atmosphérique ou dues à des
manœuvres;
Article 444: Dispositions contre les influences électromagnétiques.
Article 445: Protection contre les baisses de tension
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INSTALLATIONS ÉLECTRIQUES À BASSE TENSION –
Partie 4-44: Protection pour assurer la sécurité –
Protection contre les perturbations de tension
et les perturbations électromagnétiques
440.1 Domaine d'application
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.
Les règles de la présente partie ne s’appliquent pas aux réseaux de distribution d’énergie
public ou à la génération de puissance et à sa transmission (voir le domaine d’application de
la CEI 60364-1) bien que de telles perturbations peuvent être transmises dans ou entre des
installations électriques par ces réseaux.
440.2 Références normatives
Les documents de référence suivants sont indispensables pour l'application du présent
document. Pour les références datées, seule l'édition citée s'applique. Pour les références
non datées, la dernière édition du document de référence s'applique (y compris les éventuels
amendements).
CEI 60038:1983, Tensions normales de la CEI
CEI 60050-604:1987, Vocabulaire Electrotechnique International – Chapitre 604: Production,
transport et distribution de l'énergie électrique – Exploitation
CEI 60364-1, Installations électriques des bâtiments – Partie 1: Principes fondamentaux,
détermination des caractéristiques générales, définitions
CEI 60364-4-41:2005, Installations électriques des bâtiments – Partie 4-41: Protection pour
assurer la sécurité – Protection contre les chocs électriques
CEI 60364-5-54:2002, Installations électriques des bâtiments − Partie 5-54: Choix et mise en
œuvre des matériels électriques − Mises à la terre, conducteurs de protection et conducteurs
1
d’équipotentialité de protection
CEI 60479-1:2005, Effets du courant sur l'homme et les animaux domestiques – Partie 1:
Aspects généraux
CEI 60664-1:2007, Coordination de l'isolement des matériels dans les systèmes (réseaux) à
basse tension – Partie 1: Principes, exigences et essais
CEI 60950-1, Matériels de traitement de l’information – Sécurité – Partie 1: Exigences
générales
CEI 61000-2-5:1995, Compatibilité électromagnétique (CEM) − Partie 2: Environnement −
Section 5: Classification des environnements électromagnétiques – Publication fondamentale
en CEM
CEI 61000-6-1, Compatibilité électromagnétique (CEM) – Partie 6-1: Normes génériques –
Immunité pour les environnements résidentiels, commerciaux et de l’industrie légère
CEI 61000-6-2, Compatibilité électromagnétique (CEM) – Partie 6-2: Normes génériques –
Immunité pour les environnements industriels
____________
1
Une troisième édition est à l’étude.
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60364-4-44 © CEI:2007 – 63 –
CEI 61000-6-3, Compatibilité électromagnétique (CEM) – Partie 6-3: Normes génériques –
Normes sur l’émission pour les environnements résidentiels, commerciaux et de l’industrie
légère
CEI 61000-6-4, Compatibilité électromagnétique (CEM) – Partie 6-4: Normes génériques –
Normes sur l’émission pour les environnements industriels
CEI 61558-2-1, Sécurité des transformateurs,alimentations, bobines d’inductance et produits
analogues – Partie 2-1: Règles particulières et essais pour transformateurs d’isolement à
enroulements séparés et alimentations incorporant des transformateurs d’isolement à
enroulements séparés pour applications d’ordre général
CEI 61558-2-4, Sécurité des transformateurs, blocs d’alimentation et analogues – Partie 2-4:
Règles particulières pour les transformateurs de séparation des circuits pour usage général
CEI 61558-2-6, Sécurité des transformateurs, blocs d’alimentation et analogues – Partie 2-6:
Règles particulières pour les transformateurs de sécurité pour usage général
CEI 61558-2-15, Sécurité des transformateurs, blocs d’alimentation et analogues – Partie 2-15:
Règles particulières pour les transformateurs de séparation de circuits pour locaux à usages
médicaux
CEI 61643 (toutes les parties), Parafoudres basse tension
CEI 61936-1, Installations électriques en courant alternatif de puissance supérieure à 1 kV -
Partie 1: Règles communes
CEI 62305-1, Protection contre la foudre – Partie 1: Principes généraux
CEI 62305-3, Protection contre la foudre – Partie 3: Dommages physiques sur les structures
et risques humains
CEI 62305-4, Protection contre la foudre – Partie 4: Réseaux de puissance et de
communication dans les structures
441 (Disponible)
442 Protection des installations électriques à basse tension contre les
surtensions temporaires dues à des défauts à la terre dans le réseau
haute tension et dues à des défauts dans le réseau basse tension
442.1 Généralités
Les exigences de cet article sont nécessaires pour assurer la sécurité des installations basse
tension contre:
– un défaut entre la haute tension et la terre dans le poste de transformation alimentant
l’installation basse tension;
– la perte du point neutre en basse tension;
– un court-circuit entre phase et neutre;
– un court-circuit entre terre et phase d’un système IT basse tension.
Les exigences pour la mise à la terre du poste sont données dans la CEI 61936-1.
442.1.1 Généralités
L’Article 442 donne des règles pour le concepteur et l’installateur du poste de transformation
et couvre les cas de défauts entre une phase haute tension et la terre d’un poste de
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transformation HT/BT. Il est nécessaire d’avoir les informations suivantes sur le réseau à
haute tension:
– le type de schéma de mise à la terre;
– la valeur maximale du courant de défaut;
– la résistance de la prise de terre.
Les paragraphes suivants considèrent quatre cas comme proposé en 442.1, qui
généralement, génèrent les surtensions temporaires les plus défavorables telles que définies
dans la CEI 60050-604 :
– défaut entre le réseau haute tension et la terre (voir 442.2);
– rupture du neutre dans le réseau à basse tension (voir 442.3);
– mise à la terre accidentelle dans un schéma IT BT (voir 442.4);
– court-circuit dans l’installation à basse tension (voir 442.5).
442.1.2 Symboles
Dans l’Article 442, les symboles suivants sont utilisés (voir la Figure 44.A1):
I partie du courant de défaut à la terre dans l'installation à haute tension qui s'écoule
E
par la prise de terre des masses du poste de transformation.
R résistance de la prise de terre du poste de transformation.
E
R résistance de la prise de terre des masses des matériels du réseau à basse tension
A
R résistance de la prise de terre du neutre du réseau à basse tension dans lequel les
B
mises à la terre du transformateur et celle du neutre sont électriquement
indépendantes
U pour les schémas TN et TT: tension nominal alternative efficace entre phase et terre
o
en schéma IT: tension nominale alternative entre phase et neutre ou conducteur de
point milieu, selon configuration
U tension de défaut à fréquence industrielle dans l'installation à basse tension entre les
f
masses et la terre lors du défaut
U contrainte à fréquence industrielle de tension entre les conducteurs actifs et les
1
masses des matériels électriques à basse tension situées dans le poste de
transformation lors du défaut
U contrainte à fréquence industrielle de tension entre les conducteurs actifs et les
2
masses des matériels électriques à basse tension de l’installation électrique à basse
tension lors du défaut
NOTE 1 La contrainte à fréquence industrielle (U et U ) est la tension apparaissant à travers l’isolation des
1 2
matériels à basse tension et à travers les parafoudres connectés à l’installation basse tension.
Les symboles complémentaires suivants sont utilisés en schéma IT dans lequel les masses
des matériels électriques à basse tension sont connectées à une prise de terre
électriquement indépendante de celle du poste de transformation.
I courant de défaut s’é
...
SLOVENSKI STANDARD
oSIST IEC 60364-4-44:2009
01-februar-2009
(OHNWULþQHLQãWDODFLMH]JUDGEGHO =DãþLWQLXNUHSL=DãþLWDSUHG
SUHQDSHWRVWPL=DãþLWDSUHGQDSHWRVWQLPLPRWQMDPLLQSUHGHOHNWURPDJQHWQLPL
PRWQMDPL
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
Ta slovenski standard je istoveten z: IEC 60364-4-44
ICS:
29.120.50 9DURYDONHLQGUXJD Fuses and other overcurrent
PHGWRNRYQD]DãþLWD protection devices
91.140.50 Sistemi za oskrbo z elektriko Electricity supply systems
oSIST IEC 60364-4-44:2009 en,fr
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST IEC 60364-4-44:2009
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oSIST IEC 60364-4-44:2009
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
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oSIST IEC 60364-4-44:2009
– 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
9
faults in the high-voltage system and due to faults in the low-voltage system .
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
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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-S system within an existing building installation .25
Figure 44.R5 – TT system within a building installation .26
Figure 44.R6 – IT system within a building installation .27
Figure 44.R7A – TN multiple-source power supply with a non-suitable multiple
connection between PEN and earth .28
Figure 44.R7B – TN multiple source power supplies to an installation with connection to
earth of the star points at one and the same point .29
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Figure 44.R8 – TT multiple-source power supplies to an installation with connection to
earth of the star points at one and the same point .30
Figure 44.R9A − Three-phase alternative power supply with a 4-pole switch .31
Figure 44.R9B – Neutral current flow in a three-phase alternative power supply with an
unsuitable 3-pole switch .32
Figure 44.R9C − Single-phase alternative power supply with 2-pole switch.33
Figure 44.R10 − Armoured cables and metal pipes entering the buildings (examples) .34
Figure 44.R11 − Illustration of measures in an existing building .35
Figure 44.R12 – Interconnected earth electrodes.36
Figure 44.R13 – Examples of protective conductors in star network .37
Figure 44.R14 – Example of multiple meshed bonding star network .38
Figure 44.R15 – Example of a common meshed bonding star network .39
Figure 44.R16 – Example of equipotential bonding networks in structures without
lightning protection systems .40
Figure 44.R17A − Separation between power and information technology cables for
cable route lengths ≤ 35 m .43
Figure 44.R17B − Separation between power and information technology cables for
cable route lengths > 35 m .43
Figure 44.R18 – Separation of cables in wiring systems.44
Figure 44.R19 – Cable arrangements in metal cable-trays .45
Figure 44.R20 – Continuity of metallic system components .46
Figure 44.R21 – Location of cables inside metallic construction elements .46
Figure 44.R22 – Connection of metallic sections.47
Figure 44.Q – Examples of how to apply d , d and d for the determination of d .53
1 2 3
Table 44.A1 – Power frequency stress voltages and power frequency fault voltage in the
low voltage system .12
Table 44.A2 – Permissible power frequency stress-voltage.13
Table 44.B – Required rated impulse withstand voltage of equipment .18
Table B.1 – Different possibilities for IT systems.51
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INTERNATIONAL ELECTROTECHNICAL COMMISSION
_______________
LOW-VOLTAGE ELECTRICAL INSTALLATIONS –
Part 4-44: Protection for safety –
Protection against voltage disturbances and
electromagnetic disturbances
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 to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60364-4-44 has been prepared by IEC technical committee 64:
Electrical installations and protection against electric shock.
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 document 64/1600/FDIS, circulated to the National Committees as Amendment 3, led to
the publication of the new edition.
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The text of this standard is based on the first edition, its Amendment 1, Amendment 2 and the
following documents:
FDIS Report on voting
64/1600/FDIS 64/1609/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all the parts in the IEC 60364 series, under the general title Low-voltage electrical
installations, can be found on the IEC website.
Future standards in this series will carry the new general title as cited above. Titles of existing
standards in this series will be updated at the time of the next edition.
The committee has decided that the contents of this publication will remain unchanged until the
maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
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INTRODUCTION
Part 4-44 of IEC 60364 covers the protection of electrical installations and measures against
voltage disturbances and electromagnetic disturbances.
The requirements are arranged into four clauses as follows:
Clause 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
Clause 443 Protection against overvoltages of atmospheric origin or due to switching
Clause 444 Measures against electromagnetic influences
Clause 445 Protection against undervoltage
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LOW-VOLTAGE ELECTRICAL INSTALLATIONS –
Part 4-44: Protection for safety –
Protection against voltage disturbances and
electromagnetic disturbances
440.1 Scope
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.
The rules of this part are not intended to apply to systems for distribution of energy to the
public, or power generation and transmission for such systems (see the scope of IEC 60364-1)
although such disturbances may be conducted into or between electrical installations via these
supply systems.
440.2 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.
IEC 60038:1983, IEC standard voltages
IEC 60050-604:1987, International Electrotechnical Vocabulary – Chapter 604: Generation,
transmission and distribution of electricity – Operation
IEC 60364-1, Low-voltage electrical installations – Part 1: Fundamental principles, assessment
of general characteristics, definitions
IEC 60364-4-41:2005, Electrical installations of buildings – Part 4-41: Protection for safety –
Protection against electric shock
IEC 60364-5-54:2002, Electrical installations of buildings − Part 5-54: Selection and erection of
1
electrical equipment – Earthing arrangements and protective bonding conductors
IEC 60479-1:2005, Effects of current on human beings and livestock – Part 1: General aspects
IEC 60664-1:2007, Insulation co-ordination for equipment within low-voltage systems – Part 1:
Principles, requirements and tests
IEC 60950-1, Information technology equipment – Safety – Part 1: General requirements
IEC 61000-2-5:1995, Electromagnetic compatibility (EMC) − Part 2: Environment − Section 5:
Classification of electromagnetic environments – Basic EMC publication
IEC 61000-6-1, Electromagnetic compatibility (EMC) – Part 6-1: Generic standards – Immunity
for residential, commercial and light-industrial environments
IEC 61000-6-2, Electromagnetic compatibility (EMC) – Part 6-2: Generic standards – Immunity
for industrial environments
___________
1
A third edition is currently in preparation.
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IEC 61000-6-3, Electromagnetic compatibility (EMC) – Part 6-3: Generic standards – Emission
standard for residential, commercial and light-industrial environments
IEC 61000-6-4, Electromagnetic compatibility (EMC) – Part 6-4: Generic standards – Emission
standard for industrial environments
IEC 61558-2-1, Safety of power transformers, power supplies, reactors and similar products –
Part 2-1: Particular requirements for tests for separating transformers and power supplies
incorporating separating transformers for general applications
IEC 61558-2-4, Safety of power transformers, power supply units and similar – Part 2-4:
Particular requirements for isolating transformers for general use
IEC 61558-2-6, Safety of power transformers, power supply units and similar – Part 2-6:
Particular requirements for safety isolating transformers for general use
IEC 61558-2-15, Safety of power transformers, power supply units and similar – Part 2-15:
Particular requirements for isolating transformers for the supply of medical locations
IEC 61643 (all parts), Low-voltage surge protective devices
IEC 61936-1, Power installations exceeding 1 kV a.c. – Part 1: Common rules
IEC 62305-1, Protection against lightning – Part 1: General principles
IEC 62305-3, Protection against lightning – Part 3: Physical damage to structures and life
hazard
IEC 62305-4, Protection against lightning – Part 4: Electrical and electronic systems within
structures
441 (Vacant)
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
442.1 Field of application
The rules of this clause provide requirements for the safety of low-voltage installation in the
event of
– a fault between the high-voltage system and earth in the transformer substation that
supplies the low-voltage installation,
– a loss of the supply neutral in the low-voltage system,
– a short-circuit between a line conductor and neutral,
– an accidental earthing of a line conductor of a low-voltage IT-system.
The requirements for the earthing arrangement at the transformer substation are given in
IEC 61936-1.
442.1.1 General requirements
As Clause 442 covers faults between a high-voltage line and the earth in the HV/LV substation,
it gives rules for the designer and installer of the substation. It is necessary to have the
following information concerning the high-voltage system:
– quality of the system earthing;
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– maximum level of earth fault current;
– resistance of the earthing arrangement.
The following subclauses consider four situations as proposed in 442.1, which generally cause
the most severe temporary overvoltages such as defined in IEC 60050-604:
– fault between the high-voltage system(s) and earth (see 442.2);
– loss of the neutral in a low-voltage system (see 442.3);
– accidental earthing of a low-voltage IT system (see 442.4);
– short-circuit in the low-voltage installation (see 442.5).
442.1.2 Symbols
In Clause 442 the following symbols are used (see Figure 44.A1):
I part of the earth fault current in the high-voltage system that flows through the earthing
E
arrangement of the transformer substation.
resistance of the earthing arrangement of the transformer substation.
R
E
R resistance of the earthing arrangement of the exposed-conductive-parts of the
A
equipment of the low-voltage installation.
R resistance of the earthing arrangement of the low-voltage system neutral, for low-
B
voltage systems in which the earthing arrangements of the transformer substation and
of the low-voltage system neutral are electrically independent.
U in TN- and TT-systems: nominal a.c. r.m.s. line voltage to earth
o
in IT-systems: nominal a.c. voltage between line conductor and neutral conductor or
mid point conductor, as appropriate
U power-frequency fault voltage that appears in the low-voltage system between exposed-
f
conductive-parts and earth for the duration of the fault.
power-frequency stress voltage between the line conductor and the exposed-
U
1
conductive-parts of the low-voltage equipment of the transformer substation during the
fault.
U power-frequency stress voltage between the line conductor and the exposed-
2
conductive-parts of the low-voltage equipment of the low-voltage installation during the
fault.
NOTE 1 The power-frequency stress voltage (U and U ) is the voltage that appears across the insulation of low-
1 2
voltage equipment and across surge protective devices connected to the low-voltage system.
The following additional symbols are used in respect of IT-systems in which the exposed-
conductive-parts of the equipment of the low-voltage installation are connected to an earthing
arrangement that is electrically independent of the earthing arrangement of the transformer
substation.
I fault current that flows through the earthing arrangement of the exposed-conductive-
h
parts of the equipment of the low-voltage installation during a period when there is a
high-voltage fault and a first fault in the low-voltage installation (see Table 44.A1).
I fault current, in accordance with 411.6.2, that flows through the earthing arrangement
d
of the exposed-conductive-parts of the low-voltage installation during the first fault in a
low-voltage system (see Table 44.A1).
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Z impedance (e.g. IMD internal impedance, artificial neutral impedance) between the low-
voltage system and an earthing arrangement.
NOTE 2 An earthing arrangement may be considered electrically independent of another earthing arrangement if a
rise of potential with respect to earth in one earthing arrangement does not cause an unacceptable rise of potential
with respect to earth in the other earthing arrangement. See IEC 61936-1.
442.2 Overvoltages in LV-systems during a high-voltage earth fault
In case of a fault to earth on the HV-side of the substation, the following types of overvoltage
may affect the LV-installation:
• power frequency fault-voltage (U );
f
• power frequency stress-voltages (U and U ).
1 2
Table 44.A1 provides the relevant methods of calculation for the different types of
overvoltages.
NOTE 1 Table
...
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