SIST EN IEC 60255-27:2025

SLOVENSKI STANDARD
01-junij-2025
Merilni releji in zaščitna oprema - 27. del: Zahteve za varnost izdelka
Measuring relays and protection equipment - Part 27: Product safety requirements
Messrelais und Schutzeinrichtungen - Teil 27: Anforderungen an die Produktsicherheit
Relais de mesure et dispositifs de protection - Partie 27: Exigences de sécurité
Ta slovenski standard je istoveten z: EN IEC 60255-27:2025
ICS:
29.120.70 Releji Relays
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 60255-27

NORME EUROPÉENNE
EUROPÄISCHE NORM April 2025
ICS 29.120.70 Supersedes EN 60255-27:2014
English Version
Measuring relays and protection equipment - Part 27: Product
safety requirements
(IEC 60255-27:2023)
Relais de mesure et dispositifs de protection - Partie 27: Messrelais und Schutzeinrichtungen - Teil 27:
Exigences de sécurité des produits Anforderungen an die Produktsicherheit
(IEC 60255-27:2023) (IEC 60255-27:2023)
This European Standard was approved by CENELEC on 2024-10-16. 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 60255-27:2025 E

European foreword
The text of document 95/516/FDIS, future edition 3 of IEC 60255-27, prepared by TC 95 "Measuring
relays and protection equipment" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN IEC 60255-27:2025.
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 60255-27:2014 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 60255-27:2023 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 60332 series NOTE Approved as EN IEC 60332 series
IEC 60384-14:2013/A1:2016 NOTE Approved as EN 60384-14:2013/A1:2016 (not modified)
IEC 60695-2-12 NOTE Approved as EN IEC 60695-2-12
IEC 60695-11-5 NOTE Approved as EN 60695-11-5
IEC 61508 series NOTE Approved as EN 61508 series
IEC 61558 series NOTE Approved as EN IEC 61558 series
IEC 61810-1 NOTE Approved as EN 61810-1
IEC 61869-1 NOTE Approved as EN IEC 61869-1
IEC 62368-1 NOTE Approved as EN IEC 62368-1
IEC 62477-1:2022 NOTE Approved as EN IEC 62477-1:2023 (not modified)
IEC 62479 NOTE Approved as EN 62479
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 60085 - Electrical insulation - Thermal evaluation EN 60085 -
and designation
IEC 60127-1 - Miniature fuses - Part 1: Definitions for EN IEC 60127-1 -
miniature fuses and general requirements
for miniature fuse-links
IEC 60255-1 - Measuring relays and protection equipment EN IEC 60255-1 -
- Part 1: Common requirements
IEC 60255-26 - Measuring relays and protection equipment EN IEC 60255-26 -
- Part 26: Electromagnetic compatibility
requirements
IEC 60352-1 - Solderless connections - Part 1: Wrapped EN 60352-1 -
connections - General requirements, test
methods and practical guidance
IEC 60352-2 - Solderless connections - Part 2: Crimped EN IEC 60352-2 -
connections - General requirements, test
methods and practical guidance
IEC 60417 - Graphical symbols for use on equipment. - -
Index, survey and compilation of the single
sheets.
IEC 60529 1989 Degrees of protection provided by EN 60529 1991
enclosures (IP Code)
- - + AC 1993
+ A1 1999 + A1 2000
+ A2 2013 + A2 2013
- - + AC 2016
IEC 60664-1 2020 Insulation coordination for equipment EN IEC 60664-1 2020
within low-voltage supply systems – Part 1:
Principles, requirements and tests
- - + AC 2020
Publication Year Title EN/HD Year
IEC 60664-3 - Insulation coordination for equipment EN 60664-3 -
within low-voltage systems - Part 3: Use of
coating, potting or moulding for protection
against pollution
IEC/TS 60695-2-20 - Fire hazard testing -- Part 2-20: - -
Glowing/hot wire based test methods - Hot-
wire coil ignitability - Apparatus, test
method and guidance
IEC 60695-11-10 - Fire hazard testing - Part 11-10: Test EN 60695-11-10 -
flames - 50 W horizontal and vertical flame
test methods
IEC 60825-1 - Safety of laser products - Part 1: EN 60825-1 -
Equipment classification and requirements
IEC 60990 2016 Methods of measurement of touch current EN 60990 2016
and protective conductor current
IEC 61010-1 2010 Safety requirements for electrical EN 61010-1 2010
equipment for measurement, control, and
laboratory use - Part 1: General
requirements
+ A1 (mod) 2016 + A1 2019
- - + AC 2019
IEC 61032 - Protection of persons and equipment by EN 61032 -
enclosures - Probes for verification
IEC 61051-2 2021 Varistors for use in electronic equipment - EN IEC 61051-2 2021
Part 2: Sectional specification for surge
suppression varistors
IEC 61180 - High-voltage test techniques for low- EN 61180 -
voltage equipment - Definitions, test and
procedure requirements, test equipment
IEC 61869-6 - Instrument transformers - Part 6: Additional EN 61869-6 -
general requirements for low-power
instrument transformers
IEC 61869-10 - Instrument transformers - Part 10: EN IEC 61869-10 -
Additional requirements for low-power
passive current transformers
IEC 61869-11 - Instrument transformers - Part 11: EN IEC 61869-11 -
Additional requirements for low-power
passive voltage transformers
IEC 62151 - Safety of equipment electrically connected - -
to a telecommunication network

IEC 60255-27 ®
Edition 3.0 2023-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Measuring relays and protection equipment –
Part 27: Product safety requirements
Relais de mesure et dispositifs de protection –
Partie 27: Exigences de sécurité des produits
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.120.70 ISBN 978-2-8322-6322-8
– 2 – IEC 60255-27:2023 © IEC 2023
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 10
2 Normative references . 10
3 Terms and definitions . 12
4 Protection against electric shock . 20
4.1 Protection from contact with hazardous-live-parts . 20
4.1.1 General . 20
4.1.2 Insulation . 21
4.1.3 Equipment enclosure and barriers . 21
4.1.4 Hazardous live terminations using stranded wire . 22
4.2 Protective impedance. 22
4.3 Accessible parts. 23
4.3.1 General . 23
4.3.2 Determination of accessible parts . 23
4.3.3 Permissible limits for accessible parts . 24
4.4 Earthing and protective bonding requirements . 25
4.4.1 General . 25
4.4.2 Insulation between live parts and accessible conductive parts . 25
4.4.3 Protective bonding . 26
4.5 Functional earthed circuits . 26
4.6 Protective conductor connection . 27
4.7 High leakage current . 27
4.8 Solid insulation . 27
4.8.1 General . 27
4.8.2 Requirements . 28
4.9 Clearances and creepage distances . 28
4.9.1 General . 28
4.9.2 Clearances . 28
4.9.3 Creepage distances . 29
4.10 Single fault conditions . 30
4.10.1 Testing in single fault condition . 30
4.10.2 Application of single fault condition . 30
4.10.3 Duration of tests . 32
4.10.4 Compliance . 32
5 Mechanical aspects . 33
5.1 Protection against mechanical hazards . 33
5.1.1 Stability . 33
5.1.2 Moving parts . 33
5.1.3 Edges and corners . 34
5.2 Mechanical requirements . 34
5.3 Mechanical security of terminations . 34
6 Flammability and resistance to fire . 34
6.1 General .
...