HD 60364-4-43:2023

Low-voltage electrical installations - Part 4-43: Protection for safety - Protection against overcurrent

IEC 60364-4-43:2023 provides requirements for: - protection of live conductors, PEN conductors, PEM conductors, and PEL conductors against the harmful effects caused by overcurrent; - coordination of measures for protection against overcurrent. This fourth edition cancels and replaces the third edition published in 2008. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) the standard has been restructured, see Table 1 (Correspondence between IEC 60364‑4‑43:2008 and this document) below; b) the measure "automatic disconnection of supply" has been designated as the preferred measure for protection against overcurrent; c) all measures except the measure "automatic disconnection of supply" have been transferred into new normative annexes to indicate that these measures are usable in certain applications and under certain restricted conditions only (see Annex A, Annex B and Annex E); d) a new clause "Terms and definitions" has been added; e) new requirements have been added for the protection of the neutral or mid-point conductor (with and without triplen harmonics).

Errichten von Niederspannungsanlagen - Teil 4-43: Schutzmaßnahmen - Schutz bei Überstrom

Installations électriques à basse tension - Partie 4-43: Protection pour assurer la sécurité - Protection contre les surintensités

IEC 60364-4-43:2023 fournit les exigences pour: - la protection des conducteurs actifs, des conducteurs PEN, des conducteurs PEM et des conducteurs PEL contre les effets nuisibles des surintensités; - la coordination des mesures de protection contre les surintensités. Cette quatrième édition annule et remplace la troisième édition parue en 2008. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: a) la norme a été restructurée, voir le Tableau 1 (Correspondance entre l'IEC 60364-4-43:2008 et le présent document) ci-après; b) la mesure "déconnexion automatique de l'alimentation" a été adoptée comme mesure préférentielle pour la protection contre les surintensités; c) toutes les mesures, à l'exception de la mesure "déconnexion automatique de l'alimentation", ont été déplacées dans de nouvelles annexes normatives pour indiquer que ces mesures sont réservées à certaines applications dans des conditions restreintes (voir l'Annexe A, l'Annexe B et l'Annexe E); d) un nouvel article "Termes et définitions" a été ajouté; e) de nouvelles exigences ont été ajoutées pour la protection du conducteur neutre ou du conducteur de point milieu (avec et sans harmoniques de rang 3 et multiples de 3).

Nizkonapetostne električne inštalacije - 4-43. del: Zaščitni ukrepi - Zaščita pred nadtoki (IEC 60364-4-43:2023)

Standard IEC 60364-4-43:2023 podaja zahteve za:
– zaščito vodnikov pod napetostjo, vodnikov PEN, vodnikov PEM in vodnikov PEL pred škodljivimi učinki nadtokov;
– usklajevanje ukrepov za zaščito pred nadtokovi.
Četrta izdaja razveljavlja in nadomešča tretjo izdajo, objavljeno leta 2008. Ta izdaja je tehnično popravljena izdaja.
Ta izdaja v primerjavi s prejšnjo vključuje naslednje pomembne tehnične spremembe:
a) standard je preoblikovan, glej preglednico 1 (primerjajva med standardom IEC 60364‑4‑43:2008 in tem dokumentom) spodaj;
b) ukrep »samodejni odklop napajanja« je določen kot priporočljiv ukrep za zaščito pred nadtokovi;
c) vsi ukrepi razen ukrepa »samodejni izklop napajanja« so preneseni v nove normativne dodatke, kar označuje, da so ti ukrepi uporabni pri določenih načinih uporabe in samo pod določenimi omejenimi pogoji (glej dodatek A, dodatek B in dodatek E);
d) dodana je nova točka »Izrazi in definicije«;
e) dodane so nove zahteve za zaščito nevtralnega ali skupnega vodnika (s trojnimi harmoniki in brez njih).

General Information

• Status: Published
• Publication Date: 31-Aug-2023
• ICS: 29.120.50 - Fuses and other overcurrent protection devices
• ICS: 91.140.50 - Electricity supply systems
• Technical Committee: CLC/TC 64 - Electrical installations and protection against electric shock
• Drafting Committee: CLC/TC 64/WG 02 - Wiring systems - Protective measures against thermal effects, overcurrent
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 01-Sep-2023
• Completion Date: 01-Sep-2023
• Ref Project: SIST HD 60364-4-43:2023 - Low-voltage electrical installations - Part 4-43: Protection for safety - Protection against overcurrent (IEC 60364-4-43:2023)

Relations

• Replaces: HD 60364-4-43:2010 - Low-voltage electrical installations - Part 4-43: Protection for safety - Protection against overcurrent
• Effective Date: 16-Aug-2016

Standards Content (Sample)

SLOVENSKI STANDARD
01-november-2023
Nizkonapetostne električne inštalacije - 4-43. del: Zaščitni ukrepi - Zaščita pred
nadtoki (IEC 60364-4-43:2023)
Low-voltage electrical installations - Part 4-43: Protection for safety - Protection against
overcurrent (IEC 60364-4-43:2023)
Errichten von Niederspannungsanlagen - Teil 4-43: Schutzmaßnahmen - Schutz bei
Überstrom (IEC 60364-4-43:2023)
Installations électriques à basse tension - Partie 4-43: Protection pour assurer la sécurité
- Protection contre les surintensités (IEC 60364-4-43:2023)
Ta slovenski standard je istoveten z: HD 60364-4-43:2023
ICS:
29.120.50 Varovalke in druga Fuses and other overcurrent
nadtokovna zaščita protection devices
91.140.50 Sistemi za oskrbo z elektriko Electricity supply systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

HARMONIZATION DOCUMENT HD 60364-4-43

DOCUMENT D'HARMONISATION
HARMONISIERUNGSDOKUMENT September 2023
ICS 91.140.50; 29.120.50 Supersedes HD 60364-4-43:2010
English Version
Low-voltage electrical installations - Part 4-43: Protection for
safety - Protection against overcurrent
(IEC 60364-4-43:2023)
Installations électriques à basse tension - Partie 4-43: Errichten von Niederspannungsanlagen - Teil 4-43:
Protection pour assurer la sécurité - Protection contre les Schutzmaßnahmen - Schutz bei Überstrom
surintensités (IEC 60364-4-43:2023)
(IEC 60364-4-43:2023)
This Harmonization Document was approved by CENELEC on 2023-08-23. CENELEC members are bound to comply with the
CEN/CENELEC Internal Regulations which stipulate the conditions for implementation of this Harmonization Document at national level.
Up-to-date lists and bibliographical references concerning such national implementations may be obtained on application to the CEN-
CENELEC Management Centre or to any CENELEC member.
This Harmonization Document exists in three official versions (English, French, German).
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. HD 60364-4-43:2023 E
European foreword
The text of document 64/2591/FDIS, future edition 4 of IEC 60364-4-43, prepared by IEC/TC 64
"Electrical installations and protection against electric shock" was submitted to the IEC-CENELEC
parallel vote and approved by CENELEC as HD 60364-4-43:2023.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2024-05-23
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2026-08-23
document have to be withdrawn
This document supersedes HD 60364-4-43:2010 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 60364-4-43:2023 was approved by CENELEC as a
European Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC 60269-2 NOTE Approved as HD 60269-2
IEC 60269-3 NOTE Approved as HD 60269-3
IEC 60269-4 NOTE Approved as EN 60269-4
IEC 60364-1 NOTE Approved as HD 60364-1
IEC 60364-4-41 NOTE Approved as HD 60364-4-41
IEC 60364-5-54:2011 NOTE Approved as HD 60364-5-54:2011 (not modified) +A11:2017
IEC 60898 (series) NOTE Approved as EN 60898 (series)
IEC 60909-0 NOTE Approved as EN 60909-0
IEC 60947-1 NOTE Approved as EN IEC 60947-1
IEC 60947-2 NOTE Approved as EN 60947-2
IEC 60947-3 NOTE Approved as EN IEC 60947-3
IEC 60947-6-2 NOTE Approved as EN IEC 60947-6-2
IEC 60947-4-1 NOTE Approved as EN IEC 60947-4-1
IEC 61009-1 NOTE Approved as EN 61009-1
IEC 61439-6 NOTE Approved as EN 61439-6
IEC 61534 (series) NOTE Approved as EN 61534 (series)
IEC 61557-9 NOTE Approved as EN 61557-9
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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.
NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the
relevant EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cencenelec.eu.
Publication Year Title EN/HD Year
IEC 60364-5-522009 Low-voltage electrical installations - Part 5- HD 60364-5-52 2011
(mod) 52: Selection and erection of electrical
equipment - Wiring systems
- -  + A11 2017
- -  + A12 2022
IEC 60364-4-43 ®
Edition 4.0 2023-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Low-voltage electrical installations –

Part 4-43: Protection for safety – Protection against overcurrent

Installations électriques à basse tension –

Partie 4-43: Protection pour assurer la sécurité – Protection contre les

surintensités
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.120.50; 91.140.50 ISBN 978-2-8322-7031-8

– 2 – IEC 60364-4-43:2023 © IEC 2023
CONTENTS
FOREWORD . 4
430 Protection against overcurrent . 8
430.1 Scope . 8
430.2 Normative references . 8
430.3 Terms and definitions . 8
430.4 General requirements . 10
431 Protection against overcurrent by automatic disconnection of supply . 10
431.1 Protection of line conductors . 10
431.2 Protection of neutral or mid-point conductor . 10
431.2.1 AC circuits without triplen harmonics and DC circuits . 10
431.2.2 Additional requirements for IT systems . 11
431.2.3 AC system with triplen harmonics . 11
431.3 Protection against overcurrent . 12
431.3.1 Protection against both overload current and short-circuit current . 12
431.3.2 Protection against overload current only . 12
431.3.3 Protection against short-circuit current only . 12
431.4 Protection against overload current . 12
431.4.1 General . 12
431.4.2 Coordination between conductors and overload protective devices . 12
431.4.3 Protection against overload current of conductors connected in parallel . 13
431.5 Protection against short-circuit currents . 14
431.5.1 General . 14
431.5.2 Determination of prospective short-circuit currents . 14
431.5.3 Protection against short-circuit current of conductors connected in
parallel . 14
431.5.4 Requirements for protection against short-circuit current . 15
431.6 Coordination of protection against overload current and protection against
short-circuit current . 17
431.6.1 Protection afforded by one device . 17
431.6.2 Protection afforded by separate devices . 17
431.6.3 Coordination for selectivity and combined short-circuit protection . 17
Annex A (normative) Protection against overcurrent by other means . 19
A.1 General . 19
A.2 Protection against overload . 19
A.3 Protection against short-circuits . 19
Annex B (normative) Protection against overcurrent by limitation of the characteristics
of supply . 20
Annex C (informative) Protection of conductors in parallel against overcurrent . 21
C.1 General . 21
C.2 Protection against overload current of conductors connected in parallel . 21
C.3 Protection against short-circuit current of conductors connected in parallel . 24
Annex D (informative) Design current . 27
Annex E (normative) Cases where automatic disconnection of supply for protection
against overcurrent can cause an increased risk . 28
Annex F (informative) List of notes concerning certain countries . 29
Bibliography . 32

IEC 60364-4-43:2023 © IEC 2023 – 3 –
Figure 1 – Coordination between conductor and protective device (conditions 1 and 2) . 13
Figure C.1 – Circuit in which an overload protective device is provided for each of the
m conductors in parallel . 23
Figure C.2 – Circuit in which a single overload protective device is provided for the m
conductors in parallel . 24
Figure C.3 – Current flow at the beginning of the short-circuit . 25
Figure C.4 – Current flow after operation of the protective device D3 . 25
Figure C.5 – Illustration of linked protective device . 26

Table 1 – Correspondence between IEC 60364-4-43:2008 and this document . 6
Table 2 – Values of k for conductors . 16

– 4 – IEC 60364-4-43:2023 © IEC 2023
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE ELECTRICAL INSTALLATIONS –

Part 4-43: Protection for safety – Protection against overcurrent

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 th
...