SIST EN IEC 61109:2025

Insulators for overhead lines - Composite suspension and tension insulators for a.c. systems with a nominal voltage greater than 1 000 V - Definitions, test methods and acceptance criteria (IEC 61109:2025)

IEC 61109:2025 applies to composite insulators for overhead lines consisting of a load-bearing cylindrical insulating solid core consisting of fibres - usually glass - in a resin-based matrix, a housing (surrounding the insulating core) made of polymeric material and metal end fittings permanently attached to the insulating core. Composite insulators covered by this document are intended for use as suspension/tension line insulators, but these insulators could occasionally be subjected to compression or bending, for example when used as interphase-spacers. Guidance on such loads is outlined in Annex C.
The object of this document is to:
- define the terms used,
- specify test methods,
- specify acceptance criteria.
This third edition cancels and replaces the second edition published in 2008. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
- extension of this document to apply both to AC and DC systems;
- modifications of Clause 3, Terms, definitions and abbreviations;
- removal of Clause 7, Hybrid insulators, from this document;
- modifications of tests procedures recently included in IEC 62217 (hydrophobicity transfer test, stress corrosion, water diffusion test on the core with housing);
- modifications on environmental conditions;
- modifications on classification of tests and include the relevance of the interfaces;
- clarification and modification of the parameters determining the need to repeat design and type tests;
- revision of Table 1;
- revision of electrical type tests;
- revision of re-testing procedure of sample test;
- addition of a new Annex D on electric field control for AC;
- addition of a new Annex E on typical sketch for composite insulators assembly;
- addition of a new Annex F on mechanical evaluation of the adhesion between core and housing;
- addition of a new Annex G on applicability of design- and type tests for DC applications.

Isolatoren für Freileitungen - Verbund-Hänge- und -Abspannisolatoren für Wechselstromsysteme mit einer Nennspannung über 1 000 V - Begriffe, Prüfverfahren und Annahmekriterien (IEC 61109:2025)

Isolateurs pour lignes aériennes - Isolateurs composites de suspension et d'ancrage destinés aux systèmes à courant alternatif de tension nominale supérieure à 1 000 v - Définitions, méthodes d'essai et critères d'acceptation (IEC 61109:2025)

L'IEC 61109:2025 s'applique aux isolateurs composites pour lignes aériennes qui sont constitués d'un noyau isolant plein cylindrique réalisé en fibres - généralement de verre - qui supporte les charges. Ces isolateurs possèdent une matrice en résine, un revêtement (recouvrant le noyau isolant) en matériau élastomère et des armatures d'extrémité métalliques fixées au noyau isolant. Les isolateurs composites couverts par le présent document sont destinés à être utilisés pour la suspension ou l'ancrage de lignes, mais ces isolateurs peuvent parfois être sollicités en compression ou en flexion, par exemple lorsqu'ils sont utilisés comme entretoises interphases. L'Annexe C fournit des recommandations pour ces types de charges.
L'objet du présent document est de:
- définir les termes utilisés;
- spécifier les méthodes d'essai;
- spécifier les critères acceptation.
Cette troisième édition annule et remplace la deuxième édition parue en 2008. Cette édition constitue une révision technique.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
- élargissement du présent document pour inclure les systèmes à courant alternatif et à courant continu;
- modifications de l'Article 3, Termes, définitions et abréviations;
- suppression de l'Article 7, Isolateurs hybrides, dans le présent document;
- modifications des procédures d'essai récemment incluses dans l'IEC 62217 (essai de transfert d'hydrophobie, essai de corrosion sous contrainte, essai de pénétration d'eau - sur le noyau avec le revêtement);
- modifications des conditions d'environnement;
- modifications de la classification des essais et ajout de la pertinence des interfaces;
- clarification et modification des paramètres qui déterminent la nécessité de répéter les essais de conception et de type;
- révision du Tableau 1;
- révision des essais électriques de type;
- révision de la procédure de contre-épreuve de l'essai sur prélèvement;
- ajout d'une nouvelle Annexe D sur la maîtrise des champs électriques pour les applications en courant alternatif;
- ajout d'une nouvelle Annexe E sur les croquis types pour l'assemblage des isolateurs composites;
- ajout d'une nouvelle Annexe F sur l'évaluation mécanique de l'adhérence entre le noyau et le revêtement;
- ajout d'une nouvelle Annexe G sur l'applicabilité des essais de conception et de type pour les applications en courant continu.

Izolatorji za nadzemne vode - Sestavljeni obesni nosilni in strižni zatezni izolatorji za izmenične sisteme z nazivno napetostjo nad 1 000 V - Definicije, preskusne metode in prevzemna merila (IEC 61109:2025)

General Information

• Status: Published
• Public Enquiry End Date: 28-Feb-2024
• Publication Date: 19-Aug-2025
• ICS: 29.080.10 - Insulators
• ICS: 29.240.20 - Power transmission and distribution lines
• Technical Committee: IZL - Insulators
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 24-Apr-2025
• Due Date: 29-Jun-2025
• Completion Date: 20-Aug-2025
• Ref Project: EN IEC 61109:2025 - Insulators for overhead lines - Composite suspension and tension insulators for a.c. systems with a nominal voltage greater than 1 000 V - Definitions, test methods and acceptance criteria

Relations

• Revised: SIST EN 61109:2008 - Insulators for overhead lines - Composite suspension and tension insulators for a.c. systems with a nominal voltage greater than 1 000 V - Definitions, test methods and acceptance criteria (IEC 61109:2008)
• Effective Date: 26-Jul-2021

Standards Content (Sample)

SLOVENSKI STANDARD
01-september-2025
Izolatorji za nadzemne vode - Sestavljeni obesni nosilni in strižni zatezni izolatorji
za izmenične sisteme z nazivno napetostjo nad 1 000 V - Definicije, preskusne
metode in prevzemna merila (IEC 61109:2025)
Insulators for overhead lines - Composite suspension and tension insulators for a.c.
systems with a nominal voltage greater than 1 000 V - Definitions, test methods and
acceptance criteria (IEC 61109:2025)
Isolatoren für Freileitungen - Verbund-Hänge- und -Abspannisolatoren für
Wechselstromsysteme mit einer Nennspannung über 1 000 V - Begriffe, Prüfverfahren
und Annahmekriterien (IEC 61109:2025)
Isolateurs pour lignes aériennes - Isolateurs composites de suspension et d'ancrage
destinés aux systèmes à courant alternatif de tension nominale supérieure à 1 000 v -
Définitions, méthodes d'essai et critères d'acceptation (IEC 61109:2025)
Ta slovenski standard je istoveten z: EN IEC 61109:2025
ICS:
29.080.10 Izolatorji Insulators
29.240.20 Daljnovodi Power transmission and
distribution lines
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 61109

NORME EUROPÉENNE
EUROPÄISCHE NORM April 2025
ICS 29.080.10 Supersedes EN 61109:2008
English Version
Insulators for overhead lines - Composite suspension and
tension insulators for a.c. systems with a nominal voltage greater
than 1 000 V - Definitions, test methods and acceptance criteria
(IEC 61109:2025)
Isolateurs pour lignes aériennes - Isolateurs composites de Isolatoren für Freileitungen - Verbund-Hänge- und -
suspension et d'ancrage de tension supérieure à 1 000 V Abspannisolatoren mit einer Wechselspannung über 1 000
en courant alternatif et à 1 500 V en courant continu - V und einer Gleichspannung über 1500 V - Begriffe,
Définitions, méthodes d'essai et critères d'acceptation Prüfverfahren und Annahmekriterien
(IEC 61109:2025) (IEC 61109:2025)
This European Standard was approved by CENELEC on 2025-04-02. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
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
© 2025 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 61109:2025 E
European foreword
The text of document 36/609/FDIS, future edition 3 of IEC 61109, prepared by TC 36 "Insulators" was
submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN IEC 61109:2025.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2026-04-30
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2028-04-30
document have to be withdrawn
This document supersedes EN 61109:2008 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 61109:2025 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 60721-1 NOTE Approved as EN 60721-1
IEC 60721-1 NOTE Approved as EN 60721-1
IEC 60587 NOTE Approved as EN IEC 60587
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 60060-1 - High-voltage test techniques - Part 1: General EN 60060-1 -
definitions and test requirements
IEC 60383-1 - Insulators for overhead lines with a nominal EN IEC 60383-1 -
voltage above 1000 V - Part 1: Ceramic or
glass insulator units for a.c. systems -
Definitions, test methods and acceptance
criteria
IEC 60383-2 - Insulators for overhead lines with a nominal EN 60383-2 -
voltage above 1000 V - Part 2: Insulator
strings and insulator sets for a.c. systems -
Definitions, test methods and acceptance
criteria
IEC 60437 - Radio interference test on high-voltage EN IEC 60437 -
insulators
IEC 61284 - Overhead lines - Requirements and tests for EN 61284 -
fittings
IEC 61466-1 - Composite string insulator units for overhead EN 61466-1 -
lines with a nominal voltage greater than 1
000 V - Part 1: Standard strength and end
fittings
IEC 61467 - Insulators for overhead lines - Insulator strings EN 61467 -
and sets for lines with a nominal voltage
greater than 1 000 V - AC power arc tests
1 2
IEC 62217 — Polymeric HV insulators for indoor and EN IEC 62217 —
outdoor use - General definitions, test
methods and acceptance criteria

Under preparation. Stage at the time of publication: IEC/FDIS 62217:2025.
Under preparation. Stage at the time of publication: FprEN IEC 62217:2025
Publication Year Title EN/HD Year
IEC 62231 - Composite station post insulators for EN 62231 -
substations with a.c. voltages greater than 1
000 V up to 245 kV - Definitions, test methods
and acceptance criteria
ISO 3452 series Non-destructive testing – Penetrant testing EN ISO 3452 series

IEC 61109 ®
Edition 3.0 2025-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Insulators for overhead lines – Composite suspension and tension insulators

with AC voltage greater than 1 000 V and DC voltage greater than 1 500 V –

Definitions, test methods and acceptance criteria

Isolateurs pour lignes aériennes – Isolateurs composites de suspension et

d'ancrage de tension supérieure à 1 000 V en courant alternatif et à 1 500 V en

courant continu – Définitions, méthodes d'essai et critères d'acceptation

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.080.10  ISBN 978-2-8327-0210-9

– 2 – IEC 61109:2025 © IEC 2025
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms, definitions and abbreviated terms . 9
3.1 Terms and definitions . 9
3.2 Abbreviated terms . 12
4 Identification . 12
5 Environmental conditions . 12
6 Transport, storage and installation . 13
7 Tolerances . 13
8 Classification of tests. 14
8.1 Design tests . 14
8.2 Type tests . 15
8.3 Sample tests . 15
8.4 Routine tests. 15
9 Design tests . 18
9.1 General . 18
9.2 Test specimens . 18
9.2.1 Tests on interfaces and connections of end fittings . 18
9.2.2 Tracking and erosion test . 19
9.2.3 Tests on core material . 19
9.2.4 Tests on core with housing . 19
9.3 Product specific pre-stressing for tests on interfaces and connections of end
fittings . 19
9.3.1 General . 19
9.3.2 Sudden load release . 19
9.3.3 Thermal-mechanical pre-stress . 19
9.4 Assembled core load-time tests . 20
9.4.1 Test specimens . 20
9.4.2 Mechanical load test . 21
10 Type tests . 21
10.1 General . 21
10.2 Electrical tests on string insulator units . 21
10.2.1 General . 21
10.2.2 Test specimens . 22
10.2.3 Mounting arrangements for electrical tests . 22
10.2.4 Dry lightning impulse withstand voltage test. 22
10.2.5 Wet power-frequency voltage tests . 22
10.2.6 Wet switching impulse withstand voltage test . 22
10.2.7 Corona and radio interference voltage (RIV) tests. 22
10.2.8 Power arc test . 23
10.3 Damage limit proof test and test of the tightness of the interface between
end fittings and insulator housing . 23
10.3.1 Test specimens . 23
10.3.2 Performance of the test . 23

IEC 61109:2025 © IEC 2025 – 3 –
10.3.3 Evaluation of the test . 24
11 Sample tests .
...