EN 61557-9:2015

SLOVENSKI STANDARD
01-junij-2015
(OHNWULþQDYDUQRVWYQL]NRQDSHWRVWQLKUD]GHOLOQLKVLVWHPLK]DL]PHQLþQHQDSHWRVWL
GRN9LQHQRVPHUQHQDSHWRVWLGRN92SUHPD]DSUHVNXãDQMHPHUMHQMHDOL
QDG]RURYDQMH]DãþLWQLKXNUHSRYGHO2SUHPD]DXJRWDYOMDQMHPHVWDL]RODFLMVNH
RNYDUHY,7VLVWHPLK,(&
Electrical safety in low voltage distribution systems up to 1 000 v a.c. And 1 500 v d.c. -
Equipment for testing, measuring or monitoring of protective measures - Part 9:
Equipment for insulation fault location in IT systems (IEC 61557-9:2014)
Elektrische Sicherheit in Niederspannungsnetzen bis AC 1 000 V und DC 1 500 V -
Geräte zum Prüfen, Messen oder Überwachen von Schutzmaßnahmen - Teil 9:
Einrichtungen zur Isolationsfehlersuche in IT-Systemen (IEC 61557-9:2014)
Sécurité électrique dans les réseaux de distribution basse tension de 1 000 V c.a. et 1
500 V c.c - Dispositifs de contrôle, de mesure ou de surveillance de mesures de
protection - Partie 9: Dispositifs de localisation de défauts d'isolement pour réseaux IT
(IEC 61557-9:2014)
Ta slovenski standard je istoveten z: EN 61557-9:2015
ICS:
17.220.20 0HUMHQMHHOHNWULþQLKLQ Measurement of electrical
PDJQHWQLKYHOLþLQ and magnetic quantities
29.080.01 (OHNWULþQDL]RODFLMDQD Electrical insulation in
VSORãQR general
29.240.01 2PUHåMD]DSUHQRVLQ Power transmission and
GLVWULEXFLMRHOHNWULþQHHQHUJLMH distribution networks in
QDVSORãQR general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 61557-9
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2015
ICS 25.040.40 Supersedes EN 61557-9:2009
English Version
Electrical safety in low voltage distribution systems up to 1 000 V
a.c. and 1 500 V d.c. - Equipment for testing, measuring or
monitoring of protective measures - Part 9: Equipment for
insulation fault location in IT systems
(IEC 61557-9:2014)
Sécurité électrique dans les réseaux de distribution basse Elektrische Sicherheit in Niederspannungsnetzen bis AC 1
tension de 1 000 V c.a. et 1 500 V c.c - Dispositifs de 000 V und DC 1 500 V - Geräte zum Prüfen, Messen oder
contrôle, de mesure ou de surveillance de mesures de Überwachen von Schutzmaßnahmen - Teil 9: Einrichtungen
protection - Partie 9: Dispositifs de localisation de défauts zur Isolationsfehlersuche in IT-Systemen
d'isolement pour réseaux IT (IEC 61557-9:2014)
(IEC 61557-9:2014)
This European Standard was approved by CENELEC on 2015-01-15. 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.

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
© 2015 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 61557-9:2015 E
Foreword
The text of document 85/486/FDIS, future edition 3 of IEC 61557-9, prepared by IEC/TC 85 "Measuring
equipment for electrical and electromagnetic quantities" was submitted to the IEC-CENELEC parallel vote
and approved by CENELEC as EN 61557-9:2015.

The following dates are fixed:
(dop) 2015-10-15
• latest date by which the document has to be
implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2018-01-15
standards conflicting with the
document have to be withdrawn
This document supersedes EN 61557-9:2009

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).

Endorsement notice
The text of the International Standard IEC 61557-9:2014 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 60364-4-41:2005 NOTE Harmonized as HD 60364-4-41:2007.
IEC 60664-1 NOTE Harmonized as EN 60664-1.
IEC 60664-3 NOTE Harmonized as EN 60664-3.
IEC 60947-5-1:2003 NOTE Harmonized as EN 60947-5-1:2004.
IEC 60947-5-4:2002 NOTE Harmonized as EN 60947-5-4:2003.
IEC 61140 NOTE Harmonized as EN 61140.
IEC 61810-2:2011 NOTE Harmonized as EN 61810-2:2011.

- 3 - EN 61557-9:2015
Annex ZA
(normative)
Normative references to international 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 1 When 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.cenelec.eu.
Publication Year Title EN/HD Year

IEC 60068-2-1 -  Environmental testing -- Part 2-1: Tests - Test EN 60068-2-1 -
A: Cold
IEC 60068-2-2 -  Environmental testing -- Part 2-2: Tests - Test EN 60068-2-2 -
B: Dry heat
IEC 60068-2-6 -  Environmental testing -- Part 2-6: Tests - Test EN 60068-2-6 -
Fc: Vibration (sinusoidal)
IEC 60068-2-27 -  Environmental testing -- Part 2-27: Tests - EN 60068-2-27 -
Test Ea and guidance: Shock
IEC 60364-7-710 2002 Electrical installations of buildings -- Part 7- HD 60364-7-710 2012
(mod) 710: Requirements for special installations or
locations - Medical locations
+AC 2013
IEC 60529 -  Degrees of protection provided by enclosures - -
(IP Code)
IEC 60664 series Insulation coordination for equipment within EN 60664 series
low-voltage systems
IEC 60721-3-1 -  Classification of environmental conditions -- EN 60721-3-1 -
Part 3: Classification of groups of
environmental parameters and their severities
-- Section 1: Storage
IEC 60721-3-2 -  Classification of environmental conditions -- EN 60721-3-2 -
Part 3: Classification of groups of
environmental parameters and their severities
-- Section 2: Transportation
IEC 60721-3-3 -  Classification of environmental conditions -- EN 60721-3-3 -
Part 3: Classification of groups of
environmental parameters and their severities
-- Section 3: Stationary use at
weatherprotected locations
IEC 61010-1 2010 Safety requirements for electrical equipment EN 61010-1 2010
for measurement, control and laboratory use -
- Part 1: General requirements
IEC 61010-2-030 -  Safety requirements for electrical equipment EN 61010-2-030 -
for measurement, control and laboratory use -
- Part 2-030: Particular requirements for
testing and measuring circuits
IEC 61010-2-032 -  Safety requirements for electrical equipment EN 61010-2-032 -
for measurement, control, and laboratory use
-- Part 2-032: Particular requirements for
hand-held and hand-manipulated current
sensors for electrical test and measurement

IEC 61010-031 -  Safety requirements for electrical equipment EN 61010-031 -
for measurement, control and laboratory use -
- Part 031: Safety requirements for hand-held
probe assemblies for electrical measurement
and test
IEC 61326-2-2 -  Electrical equipment for measurement, control EN 61326-2-2 -
and laboratory use - EMC requirements --
Part 2-2: Particular requirements - Test
configurations, operational conditions and
performance criteria for portable test,
measuring and monitoring equipment used in
low-voltage distribution systems
IEC 61326-2-4 -  Electrical equipment for measurement, control EN 61326-2-4 -
and laboratory use - EMC requirements --
Part 2-4: Particular requirements - Test
configurations, operational conditions and
performance criteria for insulation monitoring
devices according to IEC 61557-8 and for
equipment for insulation fault location
according to IEC 61557-9
IEC 61557-1 2007 Electrical safety in low voltage distribution EN 61557-1 2007
systems up to 1 000 V a.c. and 1 500 V d.c. -
Equipment for testing, measuring or
monitoring of protective measures -- Part 1:
General requirements
IEC 61557-8 -  Electrical safety in low voltage distribution EN 61557-8 -
systems up to 1 000 v a.c. And 1 500 v d.c. -
Equipment for testing, measuring or
monitoring of protective measures -- Part 8:
insulation monitoring devices for it systems
CISPR 11 -  Industrial, scientific and medical equipment - EN 55011 -
Radio-frequency disturbance characteristics -
Limits and methods of measurement

IEC 61557-9 ®
Edition 3.0 2014-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electrical safety in low voltage distribution systems up to 1 000 V a.c. and

1 500 V d.c. – Equipment for testing, measuring or monitoring of protective

measures –
Part 9: Equipment for insulation fault location in IT systems

Sécurité électrique dans les réseaux de distribution basse tension de 1 000 V c.a.

et 1 500 V c.c. – Dispositifs de contrôle, de mesure ou de surveillance de

mesures de protection –
Partie 9: Dispositifs de localisation de défauts d'isolement pour réseaux IT

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX U
ICS 25.040.40 ISBN 978-2-8322-1976-8

– 2 – IEC 61557-9:2014 © IEC 2014
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms, definitions and abbreviations . 8
3.1 Terms, definitions, symbols and units . 8
3.2 Abbreviations . 10
4 Requirements . 10
4.1 General requirements . 10
4.2 Mandatory functions provided by an IFLS . 11
4.2.1 Location warning . 11
4.2.2 Local location warning (LLW) . 11
4.2.3 Remote location warning (RLW). 11
4.3 Optional functions provided by IFLS . 12
4.3.1 Indication of the insulation value . 12
4.3.2 Performance of the IFLS in case of the interruption of the connection to
the locating current sensor (LCS) . 12
4.4 Performance requirements . 12
4.4.1 Response sensitivity . 12
4.4.2 Locating current I . 12
L
4.4.3 Locating voltage U . 12
L
4.5 Electromagnetic compatibility (EMC) . 12
4.6 Safety requirements . 12
4.6.1 General . 12
4.6.2 Clearances and creepage distances . 12
4.6.3 Protection class and earth connection of the IFLS . 13
4.7 Climatic environmental conditions . 13
4.8 Mechanical requirements . 13
4.8.1 General . 13
4.8.2 Product mechanical robustness . 13
4.8.3 IP protection class requirements . 14
5 Marking and operating instructions . 15
5.1 Marking . 15
5.2 Operating instructions . 15
6 Tests . 16
6.1 General . 16
6.2 Type tests . 16
6.2.1 General . 16
6.2.2 Test of response sensitivity of the IFLS . 16
6.2.3 Test of the locating current I . 17
L
6.2.4 Test of the locating voltage U . 17
L
6.2.5 Test of the location warning . 17
6.2.6 Test of the indication of the insulation value . 17
6.2.7 Test of the performance of the LCI . 17
6.2.8 Voltage test . 17
6.2.9 Test of the electromagnetic compatibility (EMC) . 18
6.2.10 Test of the loss of LCS connection . 18

IEC 61557-9:2014 © IEC 2014 – 3 –
6.2.11 Test of the protection class and the earth connection of the IFLS . 18
6.2.12 Inspection of the marking and operating instructions . 18
6.2.13 Mechanical test . 18
6.2.14 Record of the type test . 18
6.3 Routine tests. 18
6.3.1 General . 18
6.3.2 Test of the response sensitivity. 18
6.3.3 Test of the location warning . 19
6.3.4 Test of the self-test function . 19
6.3.5 Voltage test . 19
6.3.6 Compliance with the tests of Clause 6 . 19
7 Overview of requirements and tests for IFLSs . 19
Annex A (normative) Equipment for insulation fault location in medical locations . 20
A.1 Scope . 20
A.2 Requirements . 20
A.2.1 General . 20
A.2.2 Performance requirements . 20
A.2.3 Electromagnetic compatibility (EMC) . 20
A.3 Marking and operating instructions . 20
A.4 Tests . 21
A.4.1 General . 21
A.4.2 Type tests . 21
Annex B (normative) Portable equipment for insulation fault location . 22
B.1 Scope . 22
B.2 Requirements . 22
B.2.1 General . 22
B.2.2 Performance requirements . 22
B.3 Marking and operating instructions . 22
B.4 Tests . 22
Annex C (informative) Example of an IFLS and explanation of upstream and
downstream system leakage capacitances . 24
C.1 Examples of an IFLS . 24
C.2 Upstream and downstream system leakage capacitance . 26
Bibliography . 27

Figure C.1 – Example of an IFLS . 25
Figure C.2 – Explanation of upstream and downstream system leakage capacitance . 26

Table 1 – Abbreviations . 10
Table 2 – Product mechanical requirements . 14
Table 3 – Minimum IP requirements for IFLS . 15
Table 4 – Reference conditions for tests in operation . 16
Table 5 – Reference conditions for storage tests . 16
Table 6 – Requirements and tests on IFLSs . 19

– 4 – IEC 61557-9:2014 © IEC 2014
Table A.1 – Additional requirements applicable to equipment for insulation fault
location in medical locations . 21
Table A.2 – Emission test for equipment for insulation fault location in medical
locations . 21

IEC 61557-9:2014 © IEC 2014 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRICAL SAFETY IN LOW VOLTAGE DISTRIBUTION SYSTEMS UP
TO 1 000 V AC AND 1 500 V DC – EQUIPMENT FOR TESTING, MEASURING
OR MONITORING OF PROTECTIVE MEASURES –

Part 9: Equipment for insulation fault location in IT systems

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 61557-9 has been prepared by IEC technical committee 85:
Measuring equipment for electrical and electromagnetic quantities.
This third edition cancels and replaces the second edition published in 2009. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) the scope, normative references, terms and definitions have been complemented;
b) abbreviations are listed and explained;
c) requirements, marking and operating instructions have been revised;
d) mandatory and optional functions have been defined and their terminology has been
adapted to IEC 61557-15;
– 6 – IEC 61557-9:2014 © IEC 2014
e) mechanical requirements have been added;
f) Clause 6 “Tests” has been revised;
g) new Tables have been added.
The text of this standard is based on the following documents:
FDIS Report on voting
85/486/FDIS 85/503/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.
This part of IEC 61557 shall be used in conjunction with Part 1.
A list of all parts in the IEC 61557 series, published under the general title Electrical safety in
low voltage distribution systems up to 1 000 V a.c. and 1 500 V d.c. – Equipment for testing,
measuring or monitoring of protective measures, 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.
IEC 61557-9:2014 © IEC 2014 – 7 –
ELECTRICAL SAFETY IN LOW VOLTAGE DISTRIBUTION SYSTEMS UP
TO 1 000 V AC AND 1 500 V DC – EQUIPMENT FOR TESTING, MEASURING
OR MONITORING OF PROTECTIVE MEASURES –

Part 9: Equipment for insulation fault location in IT systems

1 Scope
This part of IEC 61557 specifies the requirements for the insulation fault location system
(IFLS) which localizes insulation faults in any part of the system in unearthed IT a.c. systems
and unearthed IT a.c. systems with galvanically connected d.c. circuits having nominal
voltages up to 1 000 V a.c., as well as in unearthed IT d.c. systems with voltages up to
1 500 V d.c., independent of the measuring principle.
IT systems are described in IEC 60364-4-41 amongst other literature. Additional data for a
selection of devices in other standards should be noted.
NOTE Further information on insulation fault location can be found in the following standards:
IEC 60364-4-41:2005, 411.6, and IEC 60364-5-53:2001, 531.3.
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 60068-2-1, Environmental testing – Part 2-1: Tests – Test A: Cold
IEC 60068-2-2, Environmental testing – Part 2-2: Tests – Test B: Dry heat
IEC 60068-2-6, Environmental testing – Part 2-6: Tests – Test Fc: Vibration (sinusoidal)
IEC 60068-2-27, Environmental testing – Part 2-27: Tests – Test Ea and guidance: Shock
IEC 60364-7-710:2002, Electrical installations of buildings – Part 7-710: Requirements for
special installations or locations – Medical locations
IEC 60529, Degree of protection provided by enclosures (IP Code)
IEC 60664 (all parts): Insulation coordination for equipment within low-voltage systems
IEC 60721-3-1, Classification of environmental conditions – Part 3: Classification of groups of
environmental parameters and their severities – Section 1: Storage
IEC 60721-3-2, Classification of environmental conditions – Part 3: Classification of groups of
environmental parameters and their severities – Section 2: Transportation
IEC 60721-3-3, Classification of environmental conditions – Part 3-3: Classification of groups
of environmental parameters and their severities – Stationary use at weatherprotected
locations
– 8 – IEC 61557-9:2014 © IEC 2014
IEC 61010-1:2010, Safety requirements for electrical equipment for measurement, control,
and laboratory use – Part 1: General requirements
IEC 61010-2-030, Safety requirements for electrical equipment for measurement, control, and
laboratory use – Part 2-030: Particular requirements for testing and measuring circuits
IEC 61010-031, Safety requirements for electrical equipment for measurement, control and
laboratory use – Part 031: Safety requirements for hand-held probe assemblies for
measurement and test
IEC 61010-2-032, Safety requirements for electrical equipment for measurement, control, and
laboratory use – Part 2-032: Particular requirements for hand-held and hand-manipulated
current sensors for electrical test and measurement
IEC 61326-2-2, Electrical equipment for measurement, control and laboratory use – EMC
requirements – Part 2-2: Particular requirements – Test configurations, operational conditions
and performance criteria for portable test, measuring and monitoring equipment used in low-
voltage distribution systems
IEC 61326-2-4, Electrical equipment for measurement, control and laboratory use – EMC
requirements – Part 2-4: Particular requirements – Test configurations, operational conditions
and performance criteria for insulation monitoring devices according to IEC 61557-8 and for
equipment for insulation fault location according to IEC 61557-9
IEC 61557-1:2007, Electrical safety in low voltage distribution systems up to 1 000 V a.c. and
1 500 V d.c. – Equipment for testing, measuring or monitoring of protective measures – Part 1:
General requirements
IEC 61557-8, Electrical safety in low voltage distribution systems up to 1 000 V a.c. and
1 500 V d.c. – Equipment for testing, measuring or monitoring of protective measures – Part 8:
Insulation monitoring devices for IT systems
CISPR 11, Industrial, scientific and medical equipment - Radio-frequency disturbance
characteristics - Limits and methods of measurement
3 Terms, definitions and abbreviations
3.1 Terms, definitions, symbols and units
For the purposes of this document, the terms and definitions given in IEC 61557-1 and
IEC 61557-8 and the following apply.
3.1.1
insulation fault location system
IFLS
device or combination of devices used for insulation fault location in IT systems, where the
insulation fault location system is used in addition to an insulation monitoring device and is
used to locate insulation faults
Note 1 to entry: An IFLS injects a locating current between the electrical system and earth.
3.1.2
locating current
I
L
r.m.s. value of the current that is injected by the locating current injector during the location
process. The locating current can be generated by
– an independent locating voltage source, or

IEC 61557-9:2014 © IEC 2014 – 9 –
– an independent locating current source, or
– it can be driven directly from the system to be monitored
3.1.3
locating voltage
U
L
r.m.s. value of the voltage present at the measuring terminals of the locating current injector
during the measurement when the device has an independent locating voltage or current
source
Note 1 to entry: In a fault-free, de-energized system, this represents the voltage present between the terminals of
the locating device to the system to be monitored and the terminals for the connection to the PE conductor.
3.1.4
response sensitivity
value of the evaluating current or insulation resistance at which the evaluator responds under
specified conditions
Note 1 to entry: Response sensitivity can either be a fixed threshold or a response curve.
3.1.5
insulation fault locator
device or part of a device for the location of the insulation fault
3.1.6
locating current sensor
sensor for the detection of the locating current used for the location of the insulation fault
3.1.7
locating current injector
device or part of a device, which function it is to inject the locating current in the IT system in
order to locate the insulation fault
3.1.8
passive locating current injector
locating current injector that generates the locating current directly from the system to be
monitored
3.1.9
active locating current injector
locating current injector that generates the locating current from a locating voltage source
which is independent from the system to be monitored
3.1.10
equipment for insulation fault location in medical locations
specific insulation fault location equipment dedicated to locating insulations faults in IT
systems of group 2 medical locations complying with Annex A
3.1.11
response time
t
al
time required by insulation fault location equipment to respond under the conditions of A.2.2.1
3.1.12
group 2 medical locations
medical locations, where applied parts are intended to be used in applications such as
intracardiac procedures, operating theatres and vital treatment, where discontinuity (failure) of
the supply can cause danger to life

– 10 – IEC 61557-9:2014 © IEC 2014
Note 1 to entry: An intracardiac procedure is a procedure, whereby an electrical conductor is placed within the
cardiac zone of a patient or is likely to come into contact with the heart, such conductor being accessible outside
the patient's body. In this context, an electrical conductor includes insulated wires, such as cardiac pacing
electrodes or intracardiac ECG-electrodes, or insulated tubes filled with conducting fluids.
[SOURCE: IEC 60364-7-710:2002, 710.3.7]
3.1.13
portable equipment for insulation fault location
equipment used for temporary insulation fault location in IT systems instead of, or additionally,
to fixed installed insulation fault location equipment
3.2 Abbreviations
For the purposes of this document, the terms and abbreviations given in Table 1 apply.
Table 1 – Abbreviations
Abbreviation Term Clause Other referenced standard
(in this part 9)
C System leakage capacitance Figure C.2
Ld
downstream of the evaluating current
sensor
C System leakage capacitance upstream Figure C.2
Lu
of the evaluating current sensor
EMC Electromagnetic Compatibility 4.5 IEC 60050-161:1990, 161-01-
FE Functional Earth 4.6.3 IEC 61010-1
IFL Insulation Fault Locator 3.1.5, C.1
IFLS Insulation Fault Location System 3.1.1, Annex C
I Locating current 4.4.2, C.1
L
IMD Insulation Monitoring Device Annex C IEC 61557-8, 3.1.14

IP Degree of protection of enclosure 4.8.3 IEC 60050-246:2008, 426-04-
LCI Locating Current Injector 3.1.7, C.2
LCS Locating Current Sensor 3.1.6, C.1
LLW Local Location Warning 4.2.2
PE Protective Earth 4.6.3 IEC 60050-195:1998,
195-02-09
PIFL Portable Insulation Fault Locator Annex C
PLCS Portable Locating Current Sensor B.2.2.1
R Insulation resistance 6.2.2, C.2 IEC 61557-8, 3.1.2
F
RLW Remote Location Warning 4.2.3
T Transformer in an IT system Annex C

4 Requirements
4.1 General requirements
In addition to the requirements of Clause 4 of IEC 61557-1:2007, the requirements of
Clause 4 apply.
IEC 61557-9:2014 © IEC 2014 – 11 –
Equipment for insulation fault location shall be capable of localizing symmetrical as well as
asymmetrical insulation faults in an IT system and to give a location warning, if the insulation
resistance in a part of the installation falls below the response sensitivity.
If equipment for insulation fault location has a self-test function, the self-test shall not produce
an insulation fault to earth.
NOTE 1 See also IEC 61557-8.
NOTE 2 Insulation monitoring devices (IMDs) can be deactivated during the location process.
NOTE 3 Warning indication can be done by a lamp, a buzzer or by any other kind of indication.
NOTE 4 An IFLS can have a self-test function. Checking the response sensitivity is not necessary.
NOTE 5 An IFLS with an active locating current source can also be used for insulation fault location in de-
energized systems.
4.2 Mandatory functions provided by an IFLS
4.2.1 Location warning
An IFLS shall contain a visual warning device, which indicates if an insulation fault is detected
or allow connection to such a device for the indication of a fault. If externally connectable
audible signalling devices are provided, they may be fitted with a resetting facility. In this case,
after clearing a fault or resetting the device, the audible signal shall sound if a new fault
occurs. The location warning shall be either a local location warning or a remote location
warning or both together.
4.2.2 Local location warning (LLW)
This functions aims at issuing a warning signal when the insulation resistance between the
system and earth falls below the response sensitivity.
This function will include the localization of an insulation fault in an IT system including
symmetrical and asymmetrical insulation faults, an assessment of this fault and a local
warning.
A local warning should be made by visual indicators or audible signals generated by the
product implementing the function.
NOTE Usually this function is provided by the IFLS.
4.2.3 Remote location warning (RLW)
This functions aims at issuing a remote warning signal if the insulation resistance between the
system and earth falls below the response sensitivity.
This function will include the localization of an insulation fault in an IT system including
symmetrical and asymmetrical insulation faults, an assessment of this fault and a remote
warning.
A relay contact output or an electronic switching output or a data communication can be used
to report the warning remotely.
NOTE The warning output could also be used in some applications for switching.

– 12 – IEC 61557-9:2014 © IEC 2014
4.3 Optional functions provided by IFLS
4.3.1 Indication of the insulation value
When an IFLS includes means for the indication of the insulation value, the uncertainty of the
indicated value shall be stated by the manufacturer.
4.3.2 Performance of the IFLS in case of the interruption of the connection to the
locating current sensor (LCS)
If provided an indication if the connection to one or more LCSs is lost in a manner that the
location function is not ensured shall be issued.
4.4 Performance requirements
4.4.1 Response sensitivity
An IFLS shall be designed in such a manner that the response sensitivity stated by the
manufacturer will be met under the specified system conditions, at a total symmetrical system
leakage capacitance of 1 µF upstream the evaluating current sensor (C = 1 µF, C = 0 µF
Lu Ld
according to Figure C.2).
Information on the influence of the system leakage capacitances higher than 1 µF on the
response sensitivity as well as possible interference from the distribution system on the
insulation fault location process shall be stated by the manufacturer.
NOTE The system leakage capacitance is the sum of the leakage capacitances of all phase conductors, including
the neutral conductor to PE.
4.4.2 Locating current I
L
The maximum locating current I shall be limited to 500 mA r.m.s., to ensure that the locating
L
current does not produce touch voltages above the conventional voltage limit (50 V a.c.,
120 V d.c.) under the first fault in the distribution system. The locating current shall not
increase above 500 mA r.m.s., under foreseeable component failures in the locating current
injector (LCI). When the locating current is adjustable, unintentional changes of the setting
shall be prevented by suitable means.
4.4.3 Locating voltage U
L
If an active locating voltage or locating current is used, the locating voltage U shall be equal
L
or below 50 V a.c. or 120 V d.c. (see IEC 60364-4-41) under no load conditions.
If an active locating voltage U above 50 V a.c. or 120 V d.c. is used the locating current shall
L
not exceed 3,5 mA a.c. (r.m.s.) or 10 mA d.c. through a pure resistance of 2 000 Ω.
4.5 Electromagnetic compatibility (EMC)
An IFLS shall comply with the EMC requirements in accordance with IEC 61326-2-4.
4.6 Safety requirements
4.6.1 General
In addition to the safety requirements of IEC 61010-1 and IEC 61010-2-030 the following
safety requirements apply.
4.6.2 Clearances and creepage distances
An IFLS shall have minimum clearances and creepage distances in accordance with
IEC 61010-1 and IEC 61010-2-030.

IEC 61557-9:2014 © IEC 2014 – 13 –
Clearances and creepage distances for fixed installed equipment according to Table 3 can be
dimensioned in accordance with IEC 60664 series.
Clearances and creepage distances shall be selected for:
– overvoltage or measuring category III or II, depending on the overvoltage or measuring
category in the system to be monitored;
– pollution degree 2.
NOTE Pollution degree 3 can be used for accessible parts on the outside of the housing.
A division into circuits with different nominal insulation voltages is permissible in device
combinations for example for IT systems with nominal voltages U higher than 1 000 V a.c.
n
and 1 500 V d.c., when the electrical connection is made via resistive, capacitive or inductive
voltage dividers and if, in the case of a fault, the occurrence of inadmissibly high touch
voltages or inadmissibly high currents to earth are prevented by circuit design features. Such
circuit design features (see IEC 61140) can be, for example, additionally provided in the form
of reliable voltage dividers or a duplication of the resistors (protect
...