SIST EN 60255-27:2014
(Main)Measuring relays and protection equipment - Part 27: Product safety requirements
Measuring relays and protection equipment - Part 27: Product safety requirements
IEC 60255-27:2013 describes the product safety requirements for measuring relays and protection equipment having a rated a.c. voltage up to 1 000 V with a rated frequency up to 65 Hz, or a rated d.c. voltage up to 1 500 V. Above these limits, IEC 60664-1 is applicable for the determination of clearance, creepage distance and withstand test voltage. This standard details essential safety requirements to minimize the risk of fire and hazards caused by electric shock or injury to the user. This new edition includes the following significant technical changes with respect to the previous edition: - the removal of tables and diagrams which are from other standards and referring instead directly to the source standard; - all aspects of IEC 60255-5 have been covered and this standard will be withdrawn.
Messrelais und Schutzeinrichtungen - Teil 27: Anforderungen an die Produktsicherheit
Relais de mesure et dispositifs de protection - Partie 27: Exigences de sécurité
La CEI 60255-27:2013 détaille les exigences de sécurité produit pour les relais de mesure et dispositifs de protection dont la tension assignée n'excède pas 1 000 V en courant alternatif avec une fréquence assignée jusqu'à 65 Hz ou 1 500 V en courant continu. Au-delà de ces limites, la CEI 60664-1 est applicable pour déterminer les distances dans l'air, les lignes de fuites et la valeur des tensions de tenue d'essai. Cette norme détaille les exigences fondamentales de sécurité pour minimiser le risque d'incendie et les dangers de choc électrique ou de blessure pour l'utilisateur. Cette nouvelle édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: - le retrait des tableaux et diagrammes qui proviennent d'autres normes et référant plutôt directement à ces standards sources; - tous les aspects de la CEI 60255-5 ont été couvert et cette norme sera retirée.
Merilni releji in zaščitna oprema - 27. del: Zahteve za varnost izdelka (IEC 60255-27:2013)
EN IEC 60255-27 opisuje zahteve za varnost izdelka za merilne releje in zaščitno opremo z naznačeno izmenično napetostjo do 1000 V z naznačeno frekvenco 65 Hz ali z naznačeno enosmerno napetostjo do 1500 V. Nad temi omejitvami se standard IEC 60664-1 uporablja za ugotavljanje zevi, plazilne razdalje in napetostne trdnosti. Ta standard podrobneje določa bistvene varnostne zahteve za zmanjšanje nevarnosti požara in nevarnosti, ki jih povzroči električni udar, ali poškodb uporabnika. Ta standard ne zajema zahtev za varnost za naprave. Zajema vse načine, kako je mogoče opremo pritrditi in uporabiti v kabinah, stojalih in ploščah, ter ponovno preskušanje. Ta standard velja tudi za pomožne naprave, kot so prespojnice, serijski upori, transformatorji itd., ki se uporabljajo skupaj z merilnimi releji in zaščitno opremo ter se preskusijo skupaj. Pomožna oprema, uporabljena skupaj z merilnimi releji in zaščitno opremo, bo morda morala biti skladna z dodatnimi zahtevami za varnost. Ta mednarodni standard je namenjen samo opisovanju zahtev za varnost izdelka, zato funkcionalne lastnosti opreme niso zajete. Zahteve za funkcionalno varnost, vključno s funkcionalno varnostjo glede elektromagnetne združljivosti, niso zajete v tem standardu. Analiza tveganja za funkcionalno varnost ni zajeta v tem standardu o varnosti izdelka. Ta standard ne določa implementacije posamezne opreme, vezij in komponent. Namen tega standarda je celovit zajem vseh vidikov varnosti izdelka ter povezanih vrst in rutinskih preskusov za merilne releje in zaščitno opremo. Ta standard zajema opremo, oblikovano kot varno pod najmanj naslednjimi okoljskimi pogoji: – uporaba v prostoru; – višina do 2000 m, po IEC 60255-1; – razpon zunanje delovne temperature, po IEC 60255-1; – največja zunanja relativna vlaga 95 %, brez kondenza, po IEC 60255-1; – nihanja električne oskrbe, po IEC 60255-1; – ustrezna kategorija prenapetosti električne oskrbe; – zunanje onesnaženje stopnje 1 in zunanje onesnaženje stopnje 2. Oprema je običajno nameščena v območju z omejenim dostopom na električni centrali, napravah ali v industrijskem/maloprodajnem okolju. Upoštevajo se okoljski pogoji, navedeni za opremo v standardu IEC 60255-1. Ta standard obravnava običajne okoljske pogoje za korozijo, ki jo povzroči vlaga, vendar ne zajema korozije, ki jo povzroči onesnažen zrak. Predvideva, da je dostop do opreme med namestitvijo, vzdrževanjem, običajnimi pogoji uporabe in prenehanjem uporabe omejen na uporabnike, ki poznajo delovne postopke za zagotavljanje varnosti.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-julij-2014
1DGRPHãþD
SIST EN 60255-27:2006
SIST EN 60255-5:2002
0HULOQLUHOHMLLQ]DãþLWQDRSUHPDGHO =DKWHYH]DYDUQRVWL]GHOND ,(&
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 60255-27:2014
ICS:
29.120.70 Releji Relays
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD
EN 60255-27
NORME EUROPÉENNE
March 2014
EUROPÄISCHE NORM
ICS 29.120.70 Supersedes EN 60255-27:2005
English version
Measuring relays and protection equipment -
Part 27: Product safety requirements
(IEC 60255-27:2013)
Relais de mesure et dispositifs de Messrelais und Schutzeinrichtungen -
protection - Teil 27: Anforderungen an die
Partie 27: Exigences de sécurité Produktsicherheit
(CEI 60255-27:2013) (IEC 60255-27:2013)
This European Standard was approved by CENELEC on 2013-11-19. 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, Former Yugoslav Republic of Macedonia, France, Germany,
Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B - 1000 Brussels
© 2014 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60255-27:2014 E
Foreword
The text of document 95/316/FDIS, future edition 2 of IEC 60255-27, prepared by IEC/TC 95
"Measuring relays and protection equipment" was submitted to the IEC-CENELEC parallel vote and
approved by CENELEC as EN 60255-27:2014.
The following dates are fixed:
• latest date by which the document has (dop) 2014-09-28
to be implemented at national level by
publication of an identical national
standard or by endorsement
(dow) 2016-11-19
• latest date by which the national
standards conflicting with the
document have to be withdrawn
This document supersedes EN 60255-27:2005.
27:2005:
a) The removal of tables and diagrams which are from other standards and referring instead
directly to the source standard.
b) All aspects of EN 60255-5 have been covered and this standard can be withdrawn.
c) Ambiguity within the standard has been removed.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such
patent rights.
This standard covers the Principle Elements of the Safety Objectives for Electrical Equipment
Designed for Use within Certain Voltage Limits (LVD - 2006/95/EC).
Endorsement notice
The text of the International Standard IEC 60255-27:2013 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 standards
indicated:
IEC 60068-3-4:2001 NOTE Harmonized in EN 60068-3-4:2001 (not modified)
IEC 60112:2003 NOTE Harmonized in EN 60112:2003 (not modified)
IEC 60127-1 NOTE Harmonized in EN 60127-1
IEC 60255-5:2000 NOTE Harmonized in EN 60255-5:2000 (not modified)
IEC 60384-14:2013 NOTE Harmonized in EN 60384-14:2013 (not modified)
IEC 60695-2-12 NOTE Harmonized in EN 60695-2-12
IEC 60695-2-13:2010 NOTE Harmonized in EN 60695-2-13:2010 (not modified)
IEC 61558 (series) NOTE Harmonized in EN 61558 (series)
IEC 61810-1:2008 NOTE Harmonized in EN 61810-1:2008 (not modified)
- 3 - EN 60255-27:2014
Annex ZA
(normative)
Normative references to i nternational publications
with their corresponding European publications
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year
IEC 60050 (series) International Electrotechnical Vocabulary - -
Part 103: Mathematics - Functions
IEC 60085 Electrical insulation - Thermal evaluation and EN 60085
designation
IEC 60255-1 Measuring relays and protection equipment - EN 60255-1
Part 1: Common requirements
IEC 60255-21-1 Electrical relays - Part 21: Vibration, shock, EN 60255-21-1
bump and seismic tests on measuring relays
and protection equipment - Section 1:
Vibration tests (sinusoidal)
IEC 60255-21-2 Electrical relays - Part 21: Vibration, shock, EN 60255-21-2
bump and seismic tests on measuring relays
and protection equipment - Section 2: Shock
and bump tests
IEC 60255-21-3 Electrical relays - Part 21: Vibration, shock, EN 60255-21-3
bump and seismic tests on measuring relays
and protection equipment - Section 3: Seismic
tests
IEC 60255-26 2013 Measuring relays and protection equipment - EN 60255-26 2013
Part 26: Electromagnetic compatibility + AC:2013
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 60352-2
connections - General requirements, test
methods and practical guidance
IEC 60417 Data- Graphical symbols for use on equipment
base
IEC 60529 1989 Degrees of protection provided by enclosures EN 60529 1991
+A1 1999 (IP Code) + corr. May 1993
+A1 2000
IEC 60664-1 2007 Insulation coordination for equipment within EN 60664-1 2007
low-voltage systems - Part 1: Principles,
requirements and tests
IEC 60664-3 2003 Insulation coordination for equipment within EN 60664-3 2003
low-voltage systems - Part 3: Use of coating,
potting or moulding for protection against
pollution
Publication Year Title EN/HD Year
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 flames - EN 60695-11-10
50 W horizontal and vertical flame test
methods
IEC 60825-1 Safety of laser products - Part 1: Equipment EN 60825-1
classification and requirements
IEC 60990 1999 Methods of measurement of touch current and EN 60990 1999
protective conductor current
IEC 61010-1 2010 Safety requirements for electrical equipment EN 61010-1 2010
for measurement, control and laboratory use -
Part 1: General requirements
IEC 61032 Protection of persons and equipment by EN 61032
enclosures - Probes for verification
IEC 61140 Protection against electric shock - Common EN 61140
aspects for installation and equipment
IEC 61180-1 1992 High-voltage test techniques for low-voltage EN 61180-1 1994
equipment - Part 1: Definitions, test and
procedure requirements
IEC 61180-2 High-voltage test techniques for low-voltage EN 61180-2
equipment - Part 2: Test equipment
IEC 62151 Safety of equipment electrically connected to - -
a telecommunication network
ISO 7000 Graphical symbols for use on equipment - - -
Registered symbols
IEC 60255-27 ®
Edition 2.0 2013-10
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
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX XD
ICS 29.120.70 ISBN 978-2-8322-1161-8
– 2 – 60255-27 © IEC:2013
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references . 10
3 Terms and definitions . 11
4 General safety requirements . 19
4.1 General . 19
4.2 Earthing requirements . 20
5 Protection against electric shock . 20
5.1 General . 20
5.1.1 Introductory remark . 20
5.1.2 Protection from contact with hazardous live parts . 20
5.1.3 Discharge of capacitors . 21
5.1.4 Protective impedance . 22
5.1.5 Accessible parts . 22
5.1.6 Bonding to the protective conductor . 25
5.1.7 Protective conductor connection . 26
5.1.8 High leakage current . 26
5.1.9 Solid insulation . 26
5.1.10 Clearances and creepage distances . 27
5.1.11 Functional earthing . 29
5.2 Single-fault conditions . 29
5.2.1 Testing in single-fault condition . 29
5.2.2 Application of single-fault condition . 30
5.2.3 Duration of tests . 31
5.2.4 Compliance . 32
6 Mechanical aspects . 33
6.1 Protection against mechanical hazards . 33
6.1.1 Stability . 33
6.1.2 Moving parts . 33
6.1.3 Edges and corners . 33
6.2 Mechanical requirements . 33
6.3 Mechanical security of terminations . 33
7 Flammability and resistance to fire . 33
7.1 General . 33
7.2 Rationale . 34
7.3 General hazards from overheating and fire . 36
7.3.1 Equipment temperature limits . 36
7.3.2 Hazardous gases and chemicals. 36
7.4 Minimization of fire risk . 37
7.4.1 General . 37
7.4.2 Eliminating or reducing the sources of ignition within the equipment . 37
7.5 Cabling and fusing. 37
7.6 Flammability of materials and components . 38
7.6.1 General . 38
7.6.2 Materials for components and other parts inside fire enclosures . 38
60255-27 © IEC:2013 – 3 –
7.6.3 Materials for fire enclosures . 39
7.6.4 Materials for components and other parts outside fire enclosures . 39
7.7 Fire ignition sources . 40
7.8 Conditions for a fire enclosure . 40
7.8.1 General . 40
7.8.2 Parts requiring a fire enclosure . 40
7.8.3 Parts not requiring a fire enclosure . 40
7.9 Requirements for primary circuits and circuits exceeding ELV limits . 41
7.10 Fire enclosures and flame barriers . 41
7.11 Assessment of the fire risk due to a single-fault condition . 43
7.11.1 Guidelines for maximum acceptable temperatures when subjecting a
circuit or component to a single-fault condition . 43
7.11.2 Temperature of windings under a normal condition or a single-fault
condition . 43
7.11.3 Compliance of equipment with requirements for protection against
the spread of fire . 43
7.12 Limited-energy circuit . 44
8 General and fundamental design requirements for safety . 45
8.1 Climatic conditions for safety . 45
8.2 Electrical connections . 45
8.3 Components . 45
8.3.1 General . 45
8.3.2 High-integrity part or component . 45
8.4 Connection to telecommunication networks . 46
8.5 Connection to other equipment . 46
8.6 Laser sources . 46
8.7 Explosion . 46
8.7.1 General . 46
8.7.2 Components at risk of explosion . 46
9 Marking, documentation and packaging . 47
9.1 Marking . 47
9.1.1 General . 47
9.1.2 Identification . 48
9.1.3 Auxiliary supplies, VT, CT, I/O (Input/Output) . 48
9.1.4 Fuses . 49
9.1.5 Measuring circuit terminals . 50
9.1.6 Terminals and operating devices . 50
9.1.7 Equipment protected by double or reinforced insulation . 51
9.1.8 Batteries . 51
9.1.9 Test voltage marking . 53
9.1.10 Warning markings . 53
9.1.11 Marking durability . 54
9.2 Documentation . 54
9.2.1 General . 54
9.2.2 Equipment ratings . 54
9.2.3 Equipment installation . 55
9.2.4 Equipment commissioning and maintenance . 55
9.2.5 Equipment operation . 56
9.3 Packaging . 56
– 4 – 60255-27 © IEC:2013
10 Type tests and routine tests. 56
10.1 General . 56
10.2 Safety type tests . 58
10.3 Routine testing or sample testing . 58
10.4 Conditions for testing . 58
10.5 Verification procedure . 58
10.6 Tests . 59
10.6.1 Climatic environmental tests . 59
10.6.2 Mechanical tests . 59
10.6.3 Clearances and creepage distances . 60
10.6.4 Safety-related electrical tests . 60
10.6.5 Electrical environment and flammability . 66
10.6.6 Reverse polarity and slow ramp test . 67
Annex A (normative) Isolation class requirements and example diagrams . 69
Annex B (normative) Rated impulse voltages . 77
Annex C (normative) Guidance for the determination of clearance, creepage distance
and withstand voltages . 78
Annex D (informative) Components . 88
Annex E (normative) External wiring terminations . 92
Annex F (informative) Examples of battery protection . 94
Bibliography . 95
Figure 1 – Flow chart showing requirements for protection against the spread of fire . 35
Figure 2 – Baffle . 42
Figure 3 – Location and extent of a flame barrier . 42
Figure 4 – Voltage ramp test . 68
Figure A.1 – Equipment with SELV input/output (I/O) . 73
Figure A.2 – Equipment with PELV input/output (I/O) . 74
Figure A.3 – Equipment with PEB input/output (I/O) . 75
Figure A.4 – Equipment with ELV input/output (I/O) . 76
Figure C.1 – Guidance for determination of clearances, creepage distances and
withstand voltages . 81
Figure F.1 – Non-rechargeable battery protection . 94
Figure F.2 – Rechargeable battery protection . 94
Table 1 – Current levels under normal conditions . 24
Table 2 – Charge or energy of capacitance levels under normal conditions . 24
Table 3 – Altitude multiplication factor . 28
Table 4 – Current levels in single-fault condition . 32
Table 5 – Maximum temperature under normal conditions and at an ambient
temperature of 40 °C . 36
Table 6 – Acceptable perforation in the bottom of an equipment case . 42
Table 7 – Insulation material of windings . 43
Table 8 – Limits of maximum available current . 44
Table 9 – Overcurrent protective device . 44
60255-27 © IEC:2013 – 5 –
Table 10 – Symbols . 52
Table 11 – Symbols for marking of test voltage(s) . 53
Table 12 – Overview of tests . 57
Table 13 – Guidance for routine and sample dielectric voltage testing for safety –
Informative . 63
Table 14 – AC test voltages . 64
Table A.1 – Circuit isolation class for product circuits/groups . 69
Table A.2 – Insulation requirement between any two circuits . 71
Table B.1 – Rated impulse voltages (waveform: 1,2/50 µs) . 77
Table C.1 – Functional insulation, pollution degree 1, overvoltage category I . 82
Table C.2 – Functional insulation, pollution degree 2, overvoltage category I . 83
Table C.3 – Functional, basic or supplementary insulation, pollution degree 1,
overvoltage category II . 83
Table C.4 – Functional, basic or supplementary insulation, pollution degree 2,
overvoltage category II . 84
Table C.5 – Functional, basic or supplementary insulation, pollution degree 1,
overvoltage category III . 84
Table C.6 – Functional, basic or supplementary insulation, pollution degree 2,
overvoltage category III . 85
Table C.7 – Double or reinforced insulation, pollution degree 1, overvoltage category
II . 85
Table C.8 – Double or reinforced insulation, pollution degree 2, overvoltage category
II . 86
Table C.9 – Double or reinforced insulation, pollution degree 1, overvoltage category
III . 86
Table C.10 – Double or reinforced insulation, pollution degree 2, overvoltage category
III . 87
Table C.11 – Test voltage multiplication factor for proving the clearance in air. 87
Table C.12 – Reduction of the pollution degree of internal environment through the
use of additional protection within the equipment . 87
Table E.1 – Range of conductor sizes to be accepted by terminals . 93
Table E.2 – Sizes of terminal studs or screws directly securing supply conductors . 93
– 6 – 60255-27 © IEC:2013
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MEASURING RELAYS AND PROTECTION EQUIPMENT –
Part 27: Product safety requirements
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 itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
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 60255-27 has been prepared by IEC technical committee 95:
Measuring relays and protection equipment.
This second edition cancels and replaces the first edition published in 2005. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition.
a) The removal of tables and diagrams which are from other standards and referring instead
directly to the source standard.
b) All aspects of IEC 60255-5 have been covered and this standard can be withdrawn.
c) Ambiguity within the standard has been removed.
60255-27 © IEC:2013 – 7 –
The text of this standard is based on the following documents:
FDIS Report on voting
95/316/FDIS 95/318/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 parts in the IEC 60255 series, published under the general title Measuring relays
and protection equipment, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability 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.
– 8 – 60255-27 © IEC:2013
INTRODUCTION
In order to demonstrate that the equipment is safe, it was previously necessary to refer to
general safety standards such as IEC 61010-1 in addition to IEC 60664-1.
These general safety standards specify requirements for general product types or product
families in order to reduce the risk of fire, electric shock or injury to the user. The product
types do not include measuring relays and protection equipment. These standards also take
into account single-fault conditions.
Reference to all these various standards created confusion due to conflicting requirements,
for example, different clearances, creepage distances and test voltages etc., for the same
rated voltages.
The aim of this standard is:
• to remove confusion due to conflicting requirements between existing standards;
• to achieve a uniform approach throughout the international industry for measuring relays
and protection equipment.
This product safety standard for measuring relays and protection equipment takes the general
product safety standards and IEC 60664-1 as the base, defining those issues specific to
measuring relays and protection equipment.
60255-27 © IEC:2013 – 9 –
MEASURING RELAYS AND PROTECTION EQUIPMENT –
Part 27: Product safety requirements
1 Scope
This part of the IEC 60255 series describes the product safety requirements for measuring
relays and protection equipment having a rated a.c. voltage up to 1 000 V with a rated
frequency up to 65 Hz, or a rated d.c. voltage up to 1 500 V. Above these limits, IEC 60664-1
is applicable for the determination of clearance, creepage distance and withstand test voltage.
This standard details essential safety requirements to minimize the risk of fire and hazards
caused by electric shock or injury to the user.
This standard does not cover the safety requirements of installations. It does cover all the
ways in which the equipment may be mounted and used in cubicles, racks and panels, and
also retesting. This standard also applies to auxiliary devices such as shunts, series resistors,
transformers, etc., that are used in conjunction with measuring relays and protection
equipment and are tested together.
Ancillary equipment used in conjunction with measuring relays and protection equipment may
need to comply with additional safety requirements.
This standard is intended to describe only product safety requirements; therefore, functional
performance of the equipment is not covered.
Functional safety requirements, including EMC functional safety, are not covered by this
standard. Functional safety risk analysis is not within the scope of this product safety
standard.
This standard does not specify the implementation of individual equipment, circuits and
components.
The object of this standard is to have a comprehensive standard that covers all aspects of
product safety and the related type and routine tests, for measuring relays and protection
equipment.
This standard applies to equipment designed to be safe at least under the following
environmental conditions:
– indoor use;
– altitude up to 2 000 m, in accordance with IEC 60255-1;
– external operating temperature range, in accordance with IEC 60255-1;
– maximum external relative humidity 95 %, non-condensing, in accordance with
IEC 60255-1;
– supply fluctuations in accordance with IEC 60255-1;
– applicable supply overvoltage category;
– external pollution degree 1 and external pollution degree 2.
The equipment will normally be installed in a restricted access area within a power station,
substation or industrial/retail environment. The environmental conditions specified for the
equipment in IEC 60255-1 apply. This standard considers the normal environmental
– 10 – 60255-27 © IEC:2013
conditions of corrosion caused by humidity but does not cover corrosion by atmospheric
pollution.
It is assumed that access to the equipment during installation, maintenance, normal service
and decommissioning is restricted to users aware of working procedures necessary to ensure
safety.
This product safety standard takes precedence over general standards for matters of safety.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60050 (all parts), International Electrotechnical Vocabulary (available at
IEC 60085, Electrical insulation – Thermal evaluation and designation
IEC 60255-1, Measuring relays and protection equipment – Part 1: Common requirements
IEC 60255-21-1, Electrical relays – Part 21: Vibration, shock, bump and seismic tests on
measuring relays and protection equipment – Section One: Vibration tests (sinusoidal)
IEC 60255-21-2, Electrical relays – Part 21: Vibration, shock, bump and seismic tests on
measuring relays and protection equipment – Section Two: Shock and bump tests
IEC 60255-21-3, Electrical relays – Part 21: Vibration, shock, bump and seismic tests on
measuring relays and protection equipment – Section 3: Seismic tests
IEC 60255-26:2013, Measuring relays and protection equipment – Part 26: Electromagnetic
compatibility requirements
IEC 60352-1, Solderless connections – Part 1: Wrapped connections – General requirements,
test methods and practical guidance
IEC 60352-2, Solderless connections – Part 2: Crimped connections – General requirements,
test methods and practical guidance
IEC 60417, Graphical symbols for use on equipment. Available at: http://www.graphical-
symbols.info/equipment
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code)
Amendment 1:1999
IEC 60664-1:2007, Insulation coordination for equipment within low-voltage systems – Part 1:
Principles, requirements and tests
IEC 60664-3:2003, Insulation coordination for equipment within low-voltage systems – Part 3:
Use of coating, potting or moulding for protection against pollution
Amendment 1:2010
_______________
1 There exists a consolidated Edition 2.1 (2001) that includes Edition 2.0 and its Amendment 1.
60255-27 © IEC:2013 – 11 –
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 flames – 50 W horizontal and vertical
flame test methods
IEC 60825-1, Safety of laser products – Part 1: Equipment classification and requirements
IEC 60990:1999, Methods of measurement of touch current and protective conductor current
IEC 61010-1:2010, Safety requirements for electrical equipment for measurement, control and
laboratory use – Part 1: General requirements
IEC 61032, Protection of persons and equipment by enclosures – Probes for verification
IEC 61140, Protection against electric shock – Common aspects for installation and
equipment
IEC 61180-1:1992, High-voltage test techniques for low-voltage equipment – Part 1:
Definitions, test and procedure requirements
IEC 61180-2, High-voltage test techniques for low-voltage equipment – Part 2: Test
equipment
IEC 62151, Safety of equipment electrically connected to a telecommunication network
ISO 7000, Graphical symbols for use on equipment – Index and synopsis. Available at:
http://www.graphical-symbols.info/equipment
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60664-1 and
IEC 60050-151-448 as well as the following apply.
3.1
accessible part
part which can be touched under normal conditions with a standard rigid or jointed test finger
as specified in 3.5.1 of IEC 61010-1:2010
Note 1 to entry: A communication circuit/network, which may be connected and taken outside the cubicle housing
the equipment, or on the front of the panel without the need to open a cover or flap to access it, should be
considered to be accessible, i.e. should it be PEB, PELV, SELV or equivalent.
[SOURCE: IEC 60050:1998, 442.01.15, modified – More details about the test finger and the
note to entry has been added.]
3.2
adjacent circuits
electric circuits which are separated from the considered circuit by the necessary basic or
double/reinforced insulation
Note 1 to entry: Circuits which are separated by more than double or reinforced insulation are not considered to
be adjacent.
_______________
Edition 3.0 currently under preparation.
– 12 – 60255-27 © IEC:2013
3.3
ambient temperature
ambient air temperature
temperature, determined under prescribed conditions, of the air surrounding the complete
equipment
Note 1 to entry: For equipment installed inside an enclosure, it is the temperature of the air outside the enclosure.
Note 2 to entry: The ambient temperature is measured at half the distance from any neighbouring equipment, but
not more than 300 mm distance from the equipment case, at middle height of the equipment, protected from direct
heat radiation from the equipment.
[SOURCE: IEC 60050:2000, 441.11.13, modified – "switching device or fuse" has been
replaced by "equipment"
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