SIST HD 60364-5-559:2012

SLOVENSKI STANDARD
01-julij-2012
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SIST HD 60364-5-559:2005
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Low-voltage electrical installations - Part 5-559: Selection and erection of electrical
equipment - Luminaires and lighting installations
Errichten von Niederspannungsanlagen - Teil 5-559: Auswahl und Errichtung elektrischer
Betriebsmittel - Leuchten und Beleuchtungsanlagen
Installations électriques à basse tension - Partie 5-559: Choix et mise en œuvre des
matériels électriques - Luminaires et installations d'éclairage
Ta slovenski standard je istoveten z: HD 60364-5-559:2012
ICS:
29.140.50 Instalacijski sistemi za Lighting installation systems
razsvetljavo
91.140.50 Sistemi za oskrbo z elektriko Electricity supply systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

HARMONIZATION DOCUMENT
HD 60364-5-559
DOCUMENT D'HARMONISATION
May 2012
HARMONISIERUNGSDOKUMENT
ICS 91.140 Supersedes HD 60364-5-559:2005 + corr. Oct.2007

English version
Low-voltage electrical installations -
Part 5-559: Selection and erection of electrical equipment -
Luminaires and lighting installations
(IEC 60364-5-55:2011, modified)

Installations électriques à basse tension - Errichten von Niederspannungsanlagen -
Partie 5-559: Choix et mise en œuvre des Teil 5-559: Auswahl und Errichtung
matériels électriques - elektrischer Betriebsmittel -
Luminaires et installations d'éclairage Leuchten und Beleuchtungsanlagen
(CEI 60364-5-55:2011, modifiée) (IEC 60364-5-55:2011, modifiziert)

This Harmonization Document was approved by CENELEC on 2012-03-14. CENELEC members are bound to
comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for implementation of this
Harmonization Document at national level.

Up-to-date lists and bibliographical references concerning such national implementations may be obtained on
application to the CEN-CENELEC Management Centre or to any CENELEC member.

This Harmonization Document exists in three official versions (English, French, German).

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, 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

Management Centre: Avenue Marnix 17, B - 1000 Brussels

© 2012 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. HD 60364-5-559:2012 E

Foreword
The text of document (64/1805/FDIS (CLAUSE 559)), future edition 2 of IEC 60364-5-55, prepared by
IEC TC 64, "Electrical installations and protection against electric shock", was submitted to the
IEC-CENELEC parallel vote and approved by CENELEC as HD 60364-5-559:2012.

A draft amendment, which covers common modifications to IEC 60364-5-55 (64/1805/FDIS (CLAUSE 559)),
was prepared by CLC/TC 64 "Electrical installations and protection against electric shock" and approved by
CENELEC.
The following dates are fixed:
(dop) 2013-03-14
• latest date by which the document has
to be implemented at national level by
publication of an identical national
standard or by endorsement
(dow) 2015-03-14
• latest date by which the national

standards conflicting with the
document have to be withdrawn
This document supersedes HD 60364-5-559:2005 + corr. Oct.2007.
HD 60364-5-559:2005 + corr. Oct.2007:

– additional requirements for connection of luminaires to the fixed wiring;
– modification of requirements regarding the fixing of luminaires;
– inclusion of alternative solutions for connecting devices used for through wiring and for connection of
luminaires to the supply;
– withdrawal of Clause 556, as HD 60364-5-56 now covers this matter.

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.

Endorsement notice
The text of the International Standard IEC 60364-5-55:2011 was approved by CENELEC as a European
Standard with agreed common modifications.

In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 60079 series NOTE  Harmonized in EN 60079 series.
IEC 60155:1993 NOTE  Harmonized as EN 60155:1995 (not modified).
IEC 60309 series NOTE  Harmonized as EN 60309 series.

IEC 60332-1-1:2004 NOTE  Harmonized as EN 60332-1-1:2004 (not modified).

IEC 60332-1-2:2004 NOTE  Harmonized as EN 60332-1-2:2004 (not modified).

IEC 60364-1:2005 NOTE  Harmonized as HD 60364-1:2008 (modified)

IEC 60364-5-52:2009 NOTE  Harmonized as HD 60364-5-52:2011 (modified)

IEC 60598-1:2008 NOTE  Harmonized as EN 60598-1:2008 (modified)

IEC 60598-2-14 NOTE  Harmonized as EN 60598-2-14.

IEC 61140 NOTE  Harmonized as EN 61140.

IEC 61241 series NOTE  Harmonized in EN 61241 series.

– 3 – HD 60364-5-559:2012
IEC 61347-1:2007 NOTE  Harmonized as EN 61347-1:2008 (modified)

IEC 61557-12 NOTE  Harmonized as EN 61557-12.

IEC 61558-2-6:2009 NOTE  Harmonized as EN 61558-2-6:2009 (not modified).

IEC 61995 series NOTE  Harmonized in EN 61995 series

COMMON MODIFICATIONS
559.3 General requirements for installations
Replace note 2 by:
NOTE 2  Concerning the correct selection of the protection and control devices, information about the currents (starting current,
harmonics, leakage current, primary ignition current, etc.) generated by the lamps should be provided.
Add Annexes ZA and ZB as follows:

– 5 – HD 60364-5-559:2012
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  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 60050-195 - International Electrotechnical Vocabulary (IEV) - -
-
Chapter 195: Earthing and protection against
electric shock
IEC 60050-826 - International Electrotechnical Vocabulary - Part - -
826: Electrical installations
IEC 60079 Series Explosive atmospheres EN 60079 Series

IEC 60245-3 - Rubber insulated cables - Rated voltages up to - -
and including 450/750 V -
Part 3: Heat resistant silicone insulated cables

IEC 60331-11 - Tests for electric cables under fire conditions - - -
Circuit integrity -
Part 11: Apparatus - Fire alone at a flame
temperature of at least 750 °C

IEC 60331-21 - Tests for electric cables under fire conditions - - -
Circuit integrity -
Part 21: Procedures and requirements - Cables
of rated voltage up to an dincluding 0,6/1,0 kV

IEC 60364-1 (mod) 2005 Low-voltage electrical installations - HD 60364-1 2008
+ corr. August 2009 Part 1: Fundamental principles, assessment of
general characteristics, definitions

IEC 60364-4-41 2005 Low-voltage electrical installations - HD 60364-4-41 2007
(mod) Part 4-41: Protection for safety - Protection + corr. July 2007
against electric shock
IEC 60364-4-42 - Low voltage electrical installations - HD 60364-4-42 -
Part 4-42: Protection for safety - Protection
against thermal effects
IEC 60364-4-43 - Low voltage electrical installations - HD 60364-4-43 -
Part 4-43: Protection for safety - Protection
against overcurrent
IEC 60364-5-53 2001 Electrical installations of buildings - - -
Part 5-53: Selection and erection of electrical
equipment - Isolation, switching and control

IEC 60364-7-712 - Electrical installations of buildings - HD 60364-7-712 -
Part 7-712: Requirements for special
installations or locations - Solar photovoltaic
(PV) power supply systems
IEC 60364-7-717 - Low-voltage electrical installations - HD 60364-7-717 -
Part 7-717: Requirements for special
installations or locations - Mobile or
transportable units
IEC 60570 - Electrical supply track systems for luminaires EN 60570 -

Publication Year Title EN/HD Year
IEC 60598 Series Luminaires EN 60598 Series

IEC 60598-2-13 2006 Luminaires - EN 60598-2-13 2006
Part 2-13: Particular requirements - Ground + corr. December 2006
recessed luminaires
IEC 60598-2-22 1997 Luminaires - EN 60598-2-22 1998
(mod) Part 2-22: Particular requirements - Luminaires + corr. October 2007
for emergency lighting
IEC 60670 Series Boxes and enclosures for electrical accessories EN 60670 Series
for household and similar fixed electrical
installations
IEC 60670-21 - Boxes and enclosures for electrical accessories EN 60670-21 -
for household and similar fixed electrical
installations -
Part 21: Particular requirements for boxes and
enclosures with provision for suspension
means
IEC 60702-1 - Mineral insulated cables and their terminations EN 60702-1 -
with a rated voltage not exceeding 750 V -
Part 1: Cables
IEC 60702-2 - Mineral insulated cables and their terminations EN 60702-2 -
with a rated voltage not exceeding 750 V -
Part 2: Terminations
IEC 60998 Series Connecting devices for low-voltage circuits for EN 60998 Series
household and similar purposes

IEC 61048 2006 Auxiliaries for lamps - Capacitors for use in EN 61048 2006
tubular fluorescent and other discharge lamp
circuits - General and safety requirements

IEC 61535 - Installation couplers intended for permanent EN 61535 -
connection in fixed installation

IEC 61995 Series Devices for the connection of luminaires for EN 61995 Series
household and similar purposes

IEC 60417 Data Graphical symbols for use on equipment - -
base
ISO 8528-12 - Reciprocating internal combustion engine - -
driven alternating current generating sets - Part
12: Emergency power supply to safety services

– 7 – HD 60364-5-559:2012
Annex ZB
(normative)
Special national conditions
Special national condition: National characteristic or practice that cannot be changed even over a long
period, e.g. climatic conditions, electrical earthing conditions.

NOTE  If it affects harmonization, it forms part of the Harmonization Document.

For the countries in which the relevant special national conditions apply these provisions are normative, for
other countries they are informative.

Clause Special national condition
559.5.1 United Kingdom
In the UK one of the following is also acceptable.

a) A ceiling rose to BS67
b) A luminaire supporting coupler to BS6972 or BS7001

c) A batten lamp holder or a pendant set to BS EN 60598
d) A luminaire to BS EN 60598
e) A suitable socket-outlet to BS 1363-2, BS546 or BS EN 60309-2

f) A plug-in lighting distribution unit to BS5733
g) A connection unit to BS 1363-4

h) Appropriate terminals enclosed in a box complying with BS 4662

Denmark
559.5.1
In Denmark, a luminaire supporting plug and socket-outlet system in accordance with
Information sheet, Electrical equipment no. 16/09 (Meddelelse el-materiel nr. 16/09) is

used.
Denmark
559.5.2
In Denmark the luminaire supporting means and its fixation to the structure of the building
shall ensure the minimal suspension of a load of 25 kg.

Denmark
559.5.3
In Denmark if no information is given in the luminaire manufacturer’s information sheet

regarding the current carrying value of the through wiring in the luminaire depending of
the installation method, the biggest fuse allowed up-stream in the installation is 10A,
which on the safe side corresponds to the current carrying capacity for a 1,5 mm Cu
conductor
In Denmark the third paragraph is replaced by the following requirement:
559.5.3
Cables for through wiring in luminaires prepared for through wiring but not delivered by

the manufacturer, shall be selected in accordance with the manufacturer’s instruction

sheet.
NOTE  In accordance to EN 60598-1 if special cables or sleeves, e.g. due to high temperatures,

are necessary, the through wiring shall always be factory assembled.

Germany
559.5.5
In Germany, groups of luminaires divided between the three line conductors of a three-
phase circuit with only one common neutral conductor shall be provided with at least one

device isolating simultaneously all line conductors.

559.10
Austria and Germany
In Austria and Germany, Table A.1 of EN 60598-2-13:2006 is included for information.

Austria and Germany
Annex B
In Austria and Germany, Table B.1 apply.

Table B.1 – Selection of luminaires and lamp controlgear according to the location and
surface of installation [ for Annex B; Germany; Clause 559.4 ; There is a use of the
following selection]
Annex B
Austria and Germany
In Austria and Germany, Table B.2 applies.

Table B.2 – Explanation of additional symbols used for luminaires and controlgear for
lamps
– 9 – HD 60364-5-559:2012
Luminaires with fluorescent lamps suitable for installation in and on
equipment, e.g. furniture, as specified in DIN VDE 0710-14
"Luminaires for furniture".
Provided one of the types of mounting stated by the manufacturer is
applied (see Table B.3) such luminaires may be fixed on equipment

consisting of materials comparable to non-combustible materials,
heavily or normally inflammable building materials even such
materials
are coated, painted or veneered.
Luminaires with limited surface temperature, suitable for installation

in or on equipment, e.g. furniture, as specified in DIN VDE 0710-14
"Luminaires for furniture".
Provided one of the types of mounting stated by the manufacturer is
applied (see Table B.3) such luminaires may be fixed on equipment
consisting of materials the fire resisting capability of which is not

known and on surfaces which are coated, painted or veneered.
Independent lamp controlgear, which may be fixed directly on non

combustible, heavily or normally inflammable building materials.
Such lamp controlgear may not reach a surface temperature

exceeding 130 °C.
Independent lamp controlgear which may be fixed also in and on
equipment (furniture). The materials of the equipment may be

coated, painted or veneered and their fire resistant capability must

not be
known. Such lamp controlgear may not reach a surface temperature

exceeding 110 °C.
Type tested luminaires suitable for locations with explosion risk.

Austria and Germany
Annex B
In Austria and Germany, Table B.3 applies.
Table B.3 – Explanation of additional symbols used for the mounting of luminaires marked

with the symbols or
IEC 60364-5-55 ®
Edition 2.0 2011-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electrical installations of buildings –
Part 5-55: Selection and erection of electrical equipment – Other equipment

Installations électriques des bâtiments –
Partie 5-55: Choix et mise en œuvre des matériels électriques – Autres matériels

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX U
ICS 91.140 ISBN 978-2-88912-845-7

– 2 – 60364-5-55 © IEC:2011
CONTENTS
FOREWORD . 3
550 Introduction . 5
550.1 Scope . 5
550.2 Normative references . 5
550.3 Terms and definitions . 6
551 Low-voltage generating sets . 7
551.1 Scope . 7
551.2 General requirements . 8
551.3 Protective measure: extra-low-voltage provided by SELV and PELV . 9
551.4 Fault protection (protection against indirect contact) . 9
551.5 Protection against overcurrent . 10
551.6 Additional requirements for installations where the generating set
provides a supply as a switched alternative to the normal supply to the
installation . 11
551.7 Additional requirements for installations where the generating set may
operate in parallel with other sources including systems for distribution
of electricity to the public . 11
551.8 Requirements for installations incorporating stationary batteries . 12
559 Luminaires and lighting installations . 13
559.1 Scope . 13
559.2 Terms and definitions . 13
559.3 General requirements for installations . 14
559.4 Protection of the surroundings against thermal effects . 14
559.5 Wiring systems for lighting installations . 14
559.6 Independent lamp controlgear, e.g. ballasts . 16
559.7 Compensation capacitors . 16
559.8 Protection against electric shock for display stands for luminaires . 16
559.9 Stroboscopic effect . 16
559.10 Ground recessed luminaires . 17
Annex A (informative) List of notes concerning certain countries . 18
Annex B (informative) Explanation of symbols used in luminaires, in controlgear for
luminaires and in the installation of the luminaires . 24
Bibliography . 26

60364-5-55 © IEC:2011 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_______________
ELECTRICAL INSTALLATIONS OF BUILDINGS –

Part 5-55: Selection and erection of electrical equipment –
Other equipment
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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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 60364-5-55 has been prepared by IEC technical committee 64:
Electrical installations and protection against electric shock.
This second edition cancels and replaces the first edition, published in 2001, its Amendment 1
(2001) and its Amendment 2 (2008).
The major technical changes with respect to the previous edition are listed below:
– additional requirements for connection of luminaires to the fixed wiring;
– modification of requirements regarding the fixing of luminaires;
– inclusion of alternative solutions for connecting devices used for through wiring and for
connection of luminaires to the supply;
– withdrawal of Clause 556, as IEC 60364-5-56 now covers this matter.

– 4 – 60364-5-55 © IEC:2011
The text of this standard is based on the following documents:
FDIS Report on voting
64/1805/FDIS 64/1813/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 60364 series, under the general title Low-voltage electrical
installations, 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 website 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.
60364-5-55 © IEC:2011 – 5 –
ELECTRICAL INSTALLATIONS OF BUILDINGS –

Part 5-55: Selection and erection of electrical equipment –
Other equipment
550 Introduction
550.1 Scope
This part of IEC 60364 covers requirements for the selection and erection of low-voltage
generating sets and for the selection and erection of luminaires and lighting installations
intended to be part of the fixed installation.
550.2 Normative references
The following referenced documents are indispensable for the application 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.
IEC 60050-195, International Electrotechnical Vocabulary – Part 195: Earthing and protection
against electric shock
IEC 60050-826, International Electrotechnical Vocabulary – Part 826: Electrical installations
IEC 60079 (all parts), Explosive atmospheres
IEC 60245-3, Rubber insulated cables – Rated voltages up to and including 450/750 V –
Part 3: Heat resistant silicone insulated cables
IEC 60331-11, Tests for electric cables under fire conditions – Circuit integrity – Part 11:
Apparatus – Fire alone at a flame temperature of at least 750 °C
IEC 60331-21, Tests for electric cables under fire conditions – Circuit integrity – Part 21:
Procedures and requirements – Cables of rated voltage up to and including 0,6/1,0 kV
IEC 60364-1:2005, Low-voltage electrical installations – Part 1: Fundamental principles,
assessment of general characteristics, definitions
IEC 60364-4-41:2005, Low-voltage electrical installations – Part 4-41: Protection for safety –
Protection against electric shock
IEC 60364-4-42, Low-voltage electrical installations – Part 4-42: Protection for safety –
Protection against thermal effects
IEC 60364-4-43, Low-voltage electrical installations – Part 4-43: Protection for safety –
Protection against overcurrent
IEC 60364-5-53:2001, Electrical installations of buildings – Part 5-53: Selection and erection
of electrical equipment – Isolation, switching and control
IEC 60364-7-712, Electrical installations of buildings – Part 7-712: Requirements for special
installations or locations – Solar photovoltaic (PV) power supply systems
IEC 60364-7-717, Low-voltage electrical installations – Part 7-717: Requirements for special
installations or locations – Mobile or transportable units
IEC 60417 (all parts), Graphical symbols for use on equipment

– 6 – 60364-5-55 © IEC:2011
IEC 60570, Electrical supply track systems for luminaires
IEC 60598 (all parts), Luminaires
IEC 60598-2-13:2006, Luminaires – Part 2-13: Particular requirements – Ground recessed
luminaires
IEC 60598-2-22:1997, Luminaires – Part 2-22: Particular requirements – Luminaires for
emergency lighting
IEC 60670 (all parts), Boxes and enclosures for electrical accessories for household and
similar fixed electrical installations
IEC 60670-21, Boxes and enclosures for electrical accessories for household and similar
fixed electrical installations – Part 21: Particular requirements for boxes and enclosures with
provision for suspension means
IEC 60702-1, Mineral insulated cables and their terminations with a rated voltage not
exceeding 750 V – Part 1: Cables
IEC 60702-2, Mineral insulated cables and their terminations with a rated voltage not
exceeding 750 V – Part 2: TÈerminations
IEC 60998 (all parts), Connecting devices for low-voltage circuits for household and similar
purposes – Part 1: General requirements
IEC 61048:2006, Auxiliaries for lamps – Capacitors for use in tubular fluorescent and other
discharge lamp circuits – General and safety requirements
IEC 61535, Installation couplers intended for permanent connection in fixed installations
IEC 61995 (all parts), Devices for the connection of luminaires for household and similar
purposes
ISO 8528-12, Reciprocating internal combustion engine driven alternating current generating
sets – Part 12: Emergency power supply to safety services
550.3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
550.3.1
self-contained battery unit
unit comprising a battery and a charging and testing unit
550.3.2
non-maintained mode
operating mode of electrical equipment, essential for safety services, operating only when the
normal supply fails
550.3.3
maintained mode
operating mode of electrical equipment, essential for safety services, operating at all times
550.3.4
safety services
those services in a building which are essential

60364-5-55 © IEC:2011 – 7 –
– for the safety of persons,
– for avoiding damage to the environment or other material
NOTE Examples of safety services include
− emergency (escape) lighting,
− fire pumps,
− fire brigade lifts,
− alarm systems, such as fire alarms, smoke alarms, CO alarms and intruder alarms,
− evacuation systems,
− smoke extraction systems,
− essential medical equipment.
550.3.5
electrical safety source
source intended to maintain the supply to electrical equipment essential for the safety
services
550.3.6
electrical supply system for safety services
see IEC 60050-826
550.3.7
rated operating time of a safety source
operating time for which a safety source is designed under normal operating conditions.
551 Low-voltage generating sets
551.1 Scope
This clause provides requirements for the selection and erection of low-voltage and extra-low
voltage generating sets intended to supply, either continuously or occasionally, all or part of
the installation. Requirements are also included for installations with the following supply
arrangements:
– supply to an installation which is not connected to a system for distribution of electricity to
the public;
– supply to an installation as an alternative to a system for distribution of electricity to the
public;
– supply to an installation in parallel with a system for distribution of electricity to the public
supply;
– appropriate combinations of the above.
This part does not apply to self-contained items of extra-low voltage electrical equipment
which incorporate both the source of energy and the energy-using load and for which a
specific product standard exists that includes the requirements for electrical safety.
NOTE Requirements of the electricity distributor should be ascertained before a generating set is installed in an
installation that is connected to a system for distribution of electricity to the public.
551.1.1 Generating sets with the following power sources are considered:
– combustion engines;
– turbines;
– electric motors;
– 8 – 60364-5-55 © IEC:2011
– photovoltaic cells (IEC 60364-7-712 also applies);
– electrochemical accumulators;
– other suitable sources.
551.1.2 Generating sets with the following electrical characteristics are considered:
– mains-excited and separately excited synchronous generators;
– mains-excited and self-excited asynchronous generators;
– mains-commutated and self-commutated static converters with or without by-pass
facilities;
– generating sets with other suitable electrical characteristics.
551.1.3 The use of generating sets for the following purposes is considered:
– supply to permanent installations;
– supply to temporary installations;
– supply to portable equipment which is not connected to a permanent installation;
– supply to mobile units (IEC 60364-7-717 also applies).
551.2 General requirements
551.2.1 The means of excitation and commutation shall be appropriate for the intended use
of the generating set and the safety and proper functioning of other sources of supply shall
not be impaired by the generating set.
NOTE See 551.7 for particular requirements where the generating set may operate in parallel with a system for
the distribution of electricity to the public.
551.2.2 The prospective short-circuit current and prospective earth fault current shall be
assessed for each source of supply or combination of sources which can operate
independently of other sources or combinations. The short-circuit breaking capacity of
protective devices within the installation and, where appropriate, connected to a system for
distribution of electricity to the public, shall not be exceeded for any of the intended methods
of operation of the sources.
NOTE Attention should be given to the power factor specified for protective devices in the installation.
551.2.3 The capacity and operating characteristics of the generating set shall be such that
danger or damage to equipment does not arise after the connection or disconnection of any
intended load as a result of the deviation of the voltage or frequency from the intended
operating range. Means shall be provided to automatically disconnect such parts of the
installation as may be necessary if the capacity of the generating set is exceeded.
NOTE 1 Attention should be given to the size of individual loads as a proportion of the capacity of the generating
set and to motor starting currents.
NOTE 2 Attention should be given to the power factor specified for protective devices in the installation.
NOTE 3 The installation of a generating set within an existing building or installation may change the conditions
of external influence for the installation (see IEC 60364-1), for example by the introduction of moving parts, parts
at high temperature or by the presence of inflammable fluids and noxious gases, etc.
551.2.4 Provision for isolation shall meet the requirements of Clause 537 for each source or
combination of sources of supply.

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551.3 Protective measure: extra-low-voltage provided by SELV and PELV
551.3.1 Additional requirements for SELV and PELV where the installation
is supplied from more than one source
Where a SELV or PELV system may be supplied by more than one source, the requirements
of 414.3 of IEC 60364-4-41:2005 shall apply to each source. Where one or more of the
sources is earthed, the requirements for PELV systems in 414.4 of IEC 60364-4-41:2005 shall
apply.
If one or more of the sources does not meet the requirements of 414.3, the system shall be
treated as a FELV system and the requirements of 411.7 of IEC 60364-4-41:2005 shall apply.
551.3.2 Additional requirements where it is necessary to maintain the supply
to an extra-low voltage system
Where it is necessary to maintain the supply to an extra-low voltage system following the loss
of one or more sources of supply, each source of supply or combination of sources of supply
which can operate independently of other sources or combinations shall be capable of
supplying the intended load of the extra-low voltage system. Provisions shall be made so that
the loss of low-voltage supply to an extra-low voltage source does not lead to danger or
damage to other extra-low voltage equipment.
NOTE Such precautions may be necessary in supplies for safety services (see Clause 35 of IEC 60364-1:2005).
551.4 Fault protection (protection against indirect contact)
551.4.1 Fault protection shall be provided for the installation in respect of each source of
supply or combination of sources of supply that can operate independently of other sources or
combinations of sources.
The fault protective provisions shall be selected or precautions shall be taken to ensure that
where fault protective provisions are achieved in different ways within the same installation or
part of an installation according to the active sources of supply, no influence shall occur or
conditions arise that could impair the effectiveness of the fault protective provisions.
NOTE This might, for example, require the use of a transformer providing electrical separation between parts of
the installation using different earthing systems.
551.4.2 The generating set shall be connected so that any provision within the installation
for protection by residual current devices in accordance with IEC 60364-4-41 remains
effective for every intended combination of sources of supply.
NOTE Connection of live parts of the generator with earth may affect the protective measures.
551.4.3 Protection by automatic disconnection of supply
551.4.3.1 General
Where the protective measure automatic disconnection of supply is used for protection
against electric shock, the requirements of Clause 411 of IEC 60364-4-41:2005 apply, except
as modified for the particular cases given in 551.4.3.2 or 551.4.3.3.
551.4.3.2 Additional requirements for installations where the generating set provides
a supply as a switched alternative to the normal supply to the installation
Protection by automatic disconnection of supply shall not rely upon the connection to the
earthed point of the distribution system when the generator is operating as a switched
alternative. A suitable means of earthing shall be provided.

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551.4.3.3 Additional requirements for installations incorporating static converters
551.4.3.3.1 Where fault protection for parts of the installation supplied by the static
converter relies upon the automatic closure of the by-pass switch and the operation of
protective devices on the supply side of the by-pass switch is not within the time required
by Clause 411 of IEC 60364-4-41:2005, supplementary equipotential bonding shall be
provided between simultaneously accessible exposed-conductive-parts and extraneous-
conductive-parts on the load side of the static converter in accordance with 415.2 of
IEC 60364-4-41:2005.
The resistance of supplementary equipotential bonding conductors required between
simultaneously accessible conductive parts shall fulfill the following condition:
50 V
R≤
I
a
where
I is the maximum earth fault current which can be supplied by the static converter alone for
a
a period of up to 5 s.
NOTE Where such equipment is intended to operate in parallel with a system for distribution of electricity to the
public, the requirements of 551.7 also apply.
551.4.3.3.2 Precautions shall be taken or equipment shall be selected so that the correct
operation of protective devices is not impaired by d.c. currents generated by a static converter
or by the presence of filters.
551.4.3.3.3 A means of isolation shall be installed on both sides of a static converter.
This requirement does not apply on the power source side of a static converter which is
integrated in the same enclosure as the power source.
551.5 Protection against overcurrent
551.5.1 Where overcurrent protection of the generating set is required, it shall be located as
near as practicable to the generator terminals.
NOTE The contribution to the prospective short-circuit current by a generating set may be time-dependent and
may be much less than the contribution made by a system where the source is a mv/lv transformer.
551.5.2 Where a generating set is intended to operate in parallel with another source of
supply, including a supply from a system for distribution of electricity to the public, or where
two or more generating sets may operate in parallel, harmonic currents shall be limited so that
the thermal rating of conductors is not exceeded.
The effects of harmonic currents may be limited as follows:
– the selection of generating sets with compensated windings;
– the provision of a suitable impedance in the connection to generator star points;
– the provision of switches which interrupt the circuit but which are interlocked so that at all
times fault protection is not impaired;
– the provision of filtering equipment;
– other suitable means.
NOTE 1 Consideration should be given to the maximum voltage which may be produced across an impedance
connected to limit harmonics.
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NOTE 2 Monitoring equipment complying with IEC 61557-12 provides information on level of disturbances
resulting from the presence of harmonics.
551.6 Additional requirements for installations where the generating set provides
a supply as a switched alternative to the normal supply to the installation
551.6.1 Precautions complying with the relevant requirements of IEC 60364-5-53 for
isolation shall be taken, so that the generator cannot operate in parallel with the public supply
system for distribution of electricity to the public. Suitable precautions may include:
– an electrical, mechanical or electro-mechanical interlock between the operating
mechanisms or control circuits of the change-over switching devices;
– a system of locks with a single transferable key;
– a three-position, break-before-make, change-over switch;
– an automatic change-over switching device with a suitable interlock;
– other means providing equivalent security of operation.
NOTE Isolation should include supplies to the control circuits of the generator.
551.6.2 For TN-S systems where the neutral is not switched, any residual current device
shall be positioned to avoid incorrect operation due to the existence of any parallel neutral-
earth path.
NOTE 1 It may be desirable in TN systems to disconnect the neutral of the installation from the neutral or PEN of
the system for distribution of electricity to the public to avoid disturbances such as induced voltage surges caused
by lightning.
NOTE 2 See also 444.4.7 of IEC 60364-4-44:2007.
551.7 Additional requirements for installations where the generating set may
operate in parallel with other sources including systems for distribution of
electricity to the public
551.7.1 Where a generating set is used as an additional source of supply in parallel with
another source, protection against thermal effects in accordance with IEC 60364-4-42 and
protection against overcurrent in accordance with IEC 60364-4-43 shall remain effective in all
situations.
Except where an uninterruptible power supply is provided to supply specific items of current
using equipment within the final circuit to which it is connected, such a generating set shall be
installed on the supply side of all the
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