IEC 61936-1:2021

Power installations exceeding 1 kV AC and 1,5 kV DC - Part 1: AC

IEC 61936-1:2021 provides requirements for the design and the erection of electrical power installations in systems with nominal voltages exceeding 1 kV AC and nominal frequency up to and including 60 Hz, so as to provide safety and proper functioning for the use intended.
This document does not apply to the design and erection of any of the following:
– overhead and underground lines between separate electrical power installations;
– electrified railway tracks and rolling stock;
– mining equipment and installations;
– fluorescent lamp installations;
– installations on ships according to IEC 60092 (all parts) and offshore units according to IEC 61892 (all parts), which are used in the offshore petroleum industry for drilling, processing and storage purposes;
– electrostatic equipment (e.g. electrostatic precipitators, spray-painting units);
– test sites;
– medical equipment, e.g. medical X-ray equipment.
This document does not apply to the design of prefabricated, type-tested switchgear and high voltage/low voltage prefabricated substation, for which separate IEC standards exist.
This edition includes the following significant technical changes with respect to the previous edition:  
introduction has been rewritten to reflect the status when this document is produced;
the scope has been improved to clarify the application of this document;
missing and obsolete terms and definitions have been updated including improvement of existing terms;
Table 1 has been updated where agreements between supplier and user are needed;
requirements of electromagnetic compatibility have been clarified;
insulation coordination clause (Clause 5) has improved wording for better clarity and the technical content has an updated coordination to the latest versions of the insulation coordination standards;
wording regarding electrical equipment has been improved and made clearer;
subclause for fuses has been improved and reworded;
requirements have been added for labelling when multiple sources are required to be disconnected;
missing requirements for GIS have been reintroduced;
subclause regarding ventilation (HVAC) has been improved;
figures in Clause 7 have been updated and moved to the corresponding subclause;
requirements for transformer installations have been improved including adjustment of editorial typing-errors;
clause on protection, automation and auxiliary systems has been restructured and improved;
protection against lightning strokes has been extended;
clarification of content due to the distinction between erection (and providing electrical safety for the intended use of the electrical power installation) and subsequent activities such as maintenance and repair with safe working procedures;
where no provincial, national or regional regulations are available for safe working procedures, an informative guideline is provided in Annex F. This replaces the former parts of Figure 3 in Clause 7.

Installations électriques de puissance de tension supérieure à 1 kV en courant alternatif et 1,5 kV en courant continu - Partie 1: Courant alternatif

L’IEC 61936-1:2021 fournit des exigences relatives à la conception et au montage des installations électriques dans des systèmes dont les tensions nominales sont supérieures à 1 kV en courant alternatif et la fréquence nominale inférieure ou égale à 60 Hz, afin d'assurer la sécurité et le fonctionnement correct pour l'utilisation prévue.
L'installation électrique comprend notamment les matériels suivants:
machines électriques tournantes;
appareillage;
transformateurs et réactances;
convertisseurs;
câbles;
canalisations électriques;
batteries;
condensateurs;
installations de mise à la terre;
bâtiments et clôtures qui font partie d'une installation électrique fermée;
systèmes associés de protection, de commande et auxiliaires;
réactance élevée à noyau d’air.  Le présent document ne s'applique pas à la conception des appareillages préfabriqués soumis à un essai de type et des postes préfabriqués à haute tension/basse tension, pour lesquels des normes IEC spécifiques existent.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:  
l’introduction a été remaniée pour refléter la réalité au moment de la rédaction du présent document;
le domaine d’application a été amélioré pour clarifier l’application du présent document;
les termes et définitions manquants et obsolètes ont été mis à jour, et les termes existants ont été améliorés;
le Tableau 1 a été mis à jour pour tenir compte des situations qui nécessitent des accords entre le fournisseur et l’utilisateur;
les exigences en matière de compatibilité électromagnétique ont été clarifiées;
la formulation de l’Article 5) relatif à la coordination de l’isolement a été améliorée et la coordination de son contenu technique avec les dernières versions des normes de coordination de l’isolement a été mise à jour;
la formulation concernant les matériels électriques a été améliorée et clarifiée;
le paragraphe relatif aux fusibles a été amélioré et reformulé;
des exigences en matière d’étiquetage ont été introduites lorsque des sources multiples doivent être déconnectées;
les exigences manquantes pour les postes sous enveloppe métallique (PSEM) ont été réintroduites;
amélioration du paragraphe relatif à la ventilation (CVC, chauffage, ventilation et climatisation);
mise à jour des chiffres dans l'Article 7 et leur déplacement vers le paragraphe correspondant;
les exigences relatives aux installations de transformateurs ont été améliorées, et les fautes de frappe ont été corrigées;
restructuration et amélioration de l’article relatif aux systèmes de protection, d’automatisation et auxiliaires;
la protection contre les coups de foudre a été étendue;
clarification du contenu en raison de la distinction entre les activités de montage (et l’assurance de la sécurité électrique pour l’utilisation prévue de l’installation électrique) et les activités consécutives (par exemple, la maintenance et la réparation) avec des procédures de travail sûres;
présence d’une ligne directrice informative dans l’Annexe F en l’absence de réglementation locale, nationale ou régionale sur les procédures de travail sûres. Cette modification se substitue aux anciennes parties de la Figure 3 à l'Article 7.

General Information

• Status: Published
• Publication Date: 06-Jul-2021
• ICS: 29.020 - Electrical engineering in general
• ICS: 29.080.01 - Electrical insulation in general
• Technical Committee: TC 99 - Insulation co-ordination and system engineering of high voltage electrical power installations above 1,0 kV AC and 1,5 kV DC
• Drafting Committee: MT 4 - TC 99/MT 4
• Current Stage: PPUB - Publication issued
• Start Date: 02-Jul-2021
• Completion Date: 07-Jul-2021

Relations

• Revises: IEC 61936-1:2010/AMD1:2014 - Amendment 1 - Power installations exceeding 1 kV a.c. - Part 1: Common rules
• Effective Date: 05-Sep-2023
• Revises: IEC 61936-1:2010/COR1:2011 - Corrigendum 1 - Power installations exceeding 1 kV a.c. - Part 1: Common rules
• Effective Date: 05-Sep-2023
• Revises: IEC 61936-1:2010 - Power installations exceeding 1 kV a.c. - Part 1: Common rules
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 61936-1 ®
Edition 3.0 2021-07
COMMENTED VERSION
INTERNATIONAL
STANDARD
colour
inside
Power installations exceeding 1 kV AC and 1,5 kV DC –
Part 1: AC
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.

IEC Central Office Tel.: [phone]
3, rue de Varembé [e-mail]
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 corrigendum or an amendment might have been published.

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(IEV) online.
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If you wish to give us your feedback on this publication or
need further assistance, please contact the Customer Service
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IEC 61936-1 ®
Edition 3.0 2021-07
COMMENTED VERSION
INTERNATIONAL
STANDARD
colour
inside
Power installations exceeding 1 kV AC and 1,5 kV DC –
Part 1: AC
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.020; 29.080.01 ISBN 978-2-8322-5014-3
– 2 – IEC 61936-1:2021 CMV © IEC 2021
CONTENTS
FOREWORD . 8
INTRODUCTION . 11

1 Scope . 12
2 Normative references . 13
3 Terms and definitions . 16
3.1 General definitions . 16
3.2 Definitions concerning electrical power installations . 19
3.3 Definitions concerning types of electrical power installations. 19
3.4 Definitions concerning safety measures against electric shock . 20
3.5 Definitions concerning clearances . 21
3.6 Definitions concerning control and protection . 23
3.7 Definitions concerning earthing. 23
4 Fundamental requirements . 27
4.1 General . 27
4.1.1 General requirements. 27
4.1.2 Agreements between supplier (manufacturer) and user. 28
4.2 Electrical requirements . 30
4.2.1 Methods of neutral earthing . 30
4.2.2 Voltage classification . 30
4.2.3 Current in normal operation . 30
4.2.4 Short-circuit current . 30
4.2.5 Rated frequency . 31
4.2.6 Corona . 31
4.2.7 Electric and magnetic fields . 31
4.2.8 Overvoltages. 32
4.2.9 Harmonics . 32
4.2.10 Electromagnetic compatibility . 32
4.3 Mechanical requirements . 32

4.3.1 Equipment and supporting structures General . 32
4.3.2 Tension load . 33
4.3.3 Erection load. 33
4.3.4 Ice load . 33
4.3.5 Wind load . 33
4.3.6 Switching forces . 33
4.3.7 Short-circuit forces . 33
4.3.8 Loss of conductor tension. 33
4.3.9 Seismic loads . 33
4.3.10 Dimensioning of supporting structures . 34
4.4 Climatic and environmental conditions . 34
4.4.1 General . 34
4.4.2 Normal conditions . 34
4.4.3 Special conditions . 36
4.5 Special Particular requirements . 37
4.5.1 Effects of small animals and micro-organisms . 37
4.5.2 Noise level . 37

4.5.3 Transport . 37
5 Insulation . 38
5.1 General . 38
5.2 Selection of insulation level . 38
5.2.1 General . 38
5.2.2 Consideration of methods of neutral earthing . 38
5.2.3 Consideration of rated withstand voltages . 38
5.3 Verification of withstand values. 39
5.4 Minimum clearances of live parts . 39
5.4.1 General . 39
5.4.2 Minimum clearances in voltage range I . 39
5.4.3 Minimum clearances in voltage range II . 40
5.5 Minimum clearances between parts under special conditions . 43
5.6 Tested connection zones . 43
6 Electrical equipment. 43
6.1 General requirements. 43
6.1.1 Selection.
6.1.2 Compliance .
6.1.1 Electrical equipment safety . 44

6.1.2 Personnel User safety . 44
6.2 Specific requirements . 44
6.2.1 Switching devices. 44
6.2.2 Power transformers and reactors . 45
6.2.3 Pref abricated type-tested switchgear . 46
6.2.4 Instrument transformers . 46
6.2.5 Surge arresters. 47
6.2.6 Capacitors . 47
6.2.7 Line traps . 47
6.2.8 Insulators . 48
6.2.9 Insulated cables. 48
6.2.10 Conductors and accessories . 50
6.2.11 Rotating electrical machines . 51
6.2.12 Generating units . 51
6.2.13 Generating unit main connections . 52
6.2.14 Static converters . 52
6.2.15 Fuses . 53
6.2.16 Electrical and mechanical interlocking . 53
7 Electrical power installations . 54
7.1 General . 54
7.1.1 General Common requirements . 54
7.1.2 Circuit arrangement . 54
7.1.3 Documentation . 55
7.1.4 Transport routes . 55
7.1.5 Aisles and access areas . 57
7.1.6 Lighting . 58
7.1.7 Operational safety . 58
7.1.8 Labelling . 58
7.2 Outdoor electrical power installations of open design . 58
7.2.1 General . 58

– 4 – IEC 61936-1:2021 CMV © IEC 2021
7.2.2 Protective barrier clearances. 59
7.2.3 Protective obstacle clearances . 59
7.2.4 Boundary clearances. 61
7.2.5 Minimum height over access area . 63
7.2.6 Clearances to buildings . 65
7.2.7 External f ences or walls and access doors . 68
7.3 Indoor electrical power installations of open design . 68
7.4 Installation of prefabricated type-tested switchgear. 69
7.4.1 General . 69
7.4.2 Additional requirements for gas-insulated metal-enclosed switchgear. 69
7.5 Requirements for buildings . 71

7.5.1 Introduction General . 71
7.5.2 Structural provisions . 71
7.5.3 Rooms for switchgear. 72
7.5.4 Maintenance and operating areas. 72
7.5.5 Doors . 72
7.5.6 Draining of insulating liquids . 73
7.5.7 Air co nd itioning and ventilation Heating, ventilation and air co nditioning
(HVAC) .
...

IEC 61936-1 ®
Edition 3.0 2021-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Power installations exceeding 1 kV AC and 1,5 kV DC –
Part 1: AC
Installations électriques de puissance de tension supérieure à 1 kV en courant
alternatif et 1,5 kV en courant continu –
Partie 1: Courant alternatif
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.
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About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.
About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.
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and French, with equivalent terms in 18 additional languages.
once a month by email.
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IEC 61936-1 ®
Edition 3.0 2021-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Power installations exceeding 1 kV AC and 1,5 kV DC –
Part 1: AC
Installations électriques de puissance de tension supérieure à 1 kV en courant
alternatif et 1,5 kV en courant continu –
Partie 1: Courant alternatif
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.020; 29.080.01 ISBN 978-2-8322-9887-9
– 2 – IEC 61936-1:2021 © IEC 2021
CONTENTS
FOREWORD . 8
INTRODUCTION . 11
1 Scope . 12
2 Normative references . 13
3 Terms and definitions . 15
3.1 General definitions . 15
3.2 Definitions concerning electrical power installations . 17
3.3 Definitions concerning types of electrical power installations. 18
3.4 Definitions concerning safety measures against electric shock . 18
3.5 Definitions concerning clearances . 19
3.6 Definitions concerning control and protection . 21
3.7 Definitions concerning earthing . 21
4 Fundamental requirements . 25
4.1 General . 25
4.1.1 General requirements . 25
4.1.2 Agreements between supplier and user . 26
4.2 Electrical requirements . 28
4.2.1 Methods of neutral earthing . 28
4.2.2 Voltage classification . 28
4.2.3 Current in normal operation . 28
4.2.4 Short-circuit current . 28
4.2.5 Rated frequency . 29
4.2.6 Corona . 29
4.2.7 Electric and magnetic fields . 29
4.2.8 Overvoltages . 30
4.2.9 Harmonics . 30
4.2.10 Electromagnetic compatibility . 30
4.3 Mechanical requirements . 30
4.3.1 General . 30
4.3.2 Tension load . 31
4.3.3 Erection load . 31
4.3.4 Ice load . 31
4.3.5 Wind load . 31
4.3.6 Switching forces . 31
4.3.7 Short-circuit forces . 31
4.3.8 Loss of conductor tension . 31
4.3.9 Seismic loads . 31
4.3.10 Dimensioning of structures . 32
4.4 Climatic and environmental conditions . 32
4.4.1 General . 32
4.4.2 Normal conditions . 32
4.4.3 Special conditions . 34
4.5 Particular requirements . 35
4.5.1 Effects of small animals and micro-organisms. 35
4.5.2 Noise level . 35
4.5.3 Transport . 35

5 Insulation . 35
5.1 General . 35
5.2 Selection of insulation level. 36
5.2.1 General . 36
5.2.2 Consideration of methods of neutral earthing . 36
5.2.3 Consideration of rated withstand voltages . 36
5.3 Verification of withstand values . 36
5.4 Minimum clearances of live parts . 37
5.4.1 General . 37
5.4.2 Minimum clearances in voltage range I . 37
5.4.3 Minimum clearances in voltage range II . 37
5.5 Minimum clearances between parts under special conditions . 40
5.6 Tested connection zones . 40
6 Electrical equipment . 40
6.1 General requirements . 40
6.1.1 Electrical equipment safety . 40
6.1.2 User safety . 40
6.2 Specific requirements . 41
6.2.1 Switching devices . 41
6.2.2 Power transformers and reactors . 41
6.2.3 Prefabricated type-tested switchgear . 42
6.2.4 Instrument transformers . 42
6.2.5 Surge arresters . 43
6.2.6 Capacitors . 43
6.2.7 Line traps . 44
6.2.8 Insulators . 44
6.2.9 Insulated cables . 44
6.2.10 Conductors and accessories . 47
6.2.11 Rotating electrical machines . 47
6.2
...