IEC 60364-5-55:2001/AMD2:2008

Amendment 2 - Electrical installations of buildings - Part 5-55: Selection and erection of electrical equipment - Other equipment

Amendement 2 - Installations électriques des bâtiments - Partie 5-55: Choix et mise en oeuvre des matériels électriques - Autres matériels

General Information

• Status: Published
• Publication Date: 12-Aug-2008
• ICS: 91.140.50 - Electricity supply systems
• Technical Committee: TC 64 - Electrical installations and protection against electric shock
• Drafting Committee: MT 9 - TC 64/MT 9
• Current Stage: DELPUB - Deleted Publication
• Start Date: 14-Dec-2011
• Completion Date: 26-Oct-2025

Relations

• Amends: IEC 60364-5-55:2001 - Electrical installations of buildings - Part 5-55: Selection and erection of electrical equipment - Other equipment
• Effective Date: 05-Sep-2023
• Revised: IEC 60364-5-55:2011 - Electrical installations of buildings - Part 5-55: Selection and erection of electrical equipment - Other equipment
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 60364-5-55
Edition 1.0 2008-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
AMENDMENT 2
AMENDEMENT 2
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 oeuvre des matériels électriques – Autres matériels

IEC 60364-5-55:2001/A2:2008
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IEC 60364-5-55
Edition 1.0 2008-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
AMENDMENT 2
AMENDEMENT 2
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 oeuvre des matériels électriques – Autres matériels

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
L
CODE PRIX
ICS 91.140.50 ISBN 2-8318-9943-5
– 2 – 60364-5-55 Amend. 2 © IEC:2008
FOREWORD
This amendment has been prepared by IEC technical committee 64: Electrical installations
and protection against electric shock.
The text of this amendment is based on the following documents:
CDV Report on voting
64/1591/CDV 64/1627RVC
Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The committee has decided that the contents of this amendment and the base publication will
remain unchanged until the maintenance result 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.
_____________
Page 3
CONTENTS
Replace the title of Annex A by the following new title:
List of notes concerning certain countries

Page 7
550 Introduction
Replace the existing text of 550.1 and 550.2 by the following new text:
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
60364-5-55 Amend. 2 © IEC:2008 – 3 –
IEC 60050(826), International Electrotechnical Vocabulary – Part 826: Electrical installations
of buildings
IEC 60079 (all parts), Electrical apparatus for explosive gas atmospheres
IEC 60245-3, Rubber insulated cables – Rated voltages up to and including 450/750 V –
Part 3: Heat resistant silicone insulated cables
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, Electrical installations of buildings – Part 4-42: Protection for safety –
Protection against thermal effects
IEC 60364-4-43, Electrical installations of buildings – Part 4-43: Protection for safety –
Protection against overcurrent
IEC 60364-5-53, 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, Electrical installations of buildings – Part 7-717: Requirements for special
installations or locations – Mobile or transportable units
IEC 60417 (all parts), Graphical symbols for use on equipment
IEC 60598 (all parts), Luminaires
IEC 61140, Protection against electric shock – Common aspects for installation and
equipment
Page 9
551 Low-voltage generating sets
Replace the existing text of Clause 551 by the following new text:
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;
– 4 – 60364-5-55 Amend. 2 © IEC:2008
– 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;
– 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.

60364-5-55 Amend. 2 © IEC:2008 – 5 –
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.
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 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 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 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).
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
– 6 – 60364-5-55 Amend. 2 © IEC:2008
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 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.
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, 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.
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;

60364-5-55 Amend. 2 © IEC:2008 – 7 –
– 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.
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.
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 protective devices for the final circuits of the installation.
551.7.2 A generating set used as an additional source of supply in parallel with another
source shall be installed:
– on the supply side of all the protective devices for the final circuits of the installation, or
– on the load side of all the protective devices for a final circuit of the installation, but in this
case all the following additional requirement shall be fulfilled:
i) the conductors of the final circuit shall meet the following requirement:

– 8 – 60364-5-55 Amend. 2 © IEC:2008
I ≥ I + I
z n g
where
I is the current-carrying capacity of the final circuit conductors;
z
I is the rated current of the protective device of the final circuit;
n
I is the rated output current of the generating set; and
g
ii) a generating set shall not be connected to a final circuit by means of a plug and
socket; and
iii) a residual current device providing protection of the final circuit in accordance with
Clause 411 or Clause 415 of IEC 60364-4-41 shall disconnect all live conductors
including the neutral conductor; and
iv) the line and neutral conductors of the final circuit and of the generating set shall not be
connected to earth downstream of the protective device of the final circuit.
NOTE Where the generating set is installed in a final circuit on the load side of all the protective devices for that
final circuit, except where the protective devices for the final circuit disconnect the line and the neutral conductors,
the disconnection time in accordance with 411.3.2 of IEC 60364-4-41 is the combination of the disconnection time
of the protective device for the final circuit and the time taken for the output voltage of the generating set to be
reduced to less than 50 V.
551.7.3 In selecting and using a generating set to run in parallel with another source,
including the system for distribution of electricity to the public, care shall be taken to avoid
adverse effects to that system and to other installations in respect of power factor, voltage
changes, harmonic distortion, d.c. current injection, unbalance, starting, synchronizing or
voltage fluctuation effects. In the case of a system for distribution of electricity to the public,
the distributor shall be consulted in respect of particular requirements. Where synchronization
is necessary, the use of automatic synchronizing systems which consider frequency, phase
and voltage is to be preferred.
551.7.4 Where a generating set is intended to run in parallel with the system for distribution
of electricity to the public, means of automatic switching shall be provided to disconnect the
generating set from the system for distribution of electricity to the public in the event of loss of
that supply or deviation of the voltage or frequency at the supply terminals from values
declared for normal supply.
The type of protection and the sensitivity and operating times depend upon the protection of
the system for distribution of electricity to the public and the number of generating sets
connected and shall be agreed by the distributor.
In case of presence of static converters, the means of switching shall be provided on the load
side of this static converter.
551.7.5 Where a generating set is intended to run in parallel with the system for distribution
of electricity to the public, means shall be provided to prevent the connection of a generating
set to the system for distribution of electricity to the public in the event of loss of that supply
or deviation of the voltage or frequency at the supply terminals from values declared for
normal supply.
551.7.6 Where a generating set is intended to run in parallel with the system for distribution
of electricity to the public, means shall be provided to enable the generating set to be isolated
from the system for distribution of electricity to the public. The accessibility of this means of
isolation shall comply with national rules and distribution system operator requirements.
551.7.7 Where a generating set may also operate as switched alternative to the distribution
system, the installation shall also comply with Clause 551.6.

60364-5-55 Amend. 2 © IEC:2008 – 9 –
551.8 Requirements for installations incorporating stationary batteries
551.8.1 Stationary batteries shall be installed so that they are accessible only to skilled or
instructed persons.
NOTE This generally requires the battery to be installed in a secure location, or, for smaller batteries, a secure
enclosu
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