IEC 60947-6-1:2021
(Main)Low-voltage switchgear and controlgear - Part 6-1: Multiple function equipment - Transfer switching equipment
Low-voltage switchgear and controlgear - Part 6-1: Multiple function equipment - Transfer switching equipment
IEC 60947-6-1:2021 applies to transfer switching equipment (TSE), to be used in power systems for ensuring the continuity of the supply and allowing the energy management of the installation, by transferring a load between power supply sources, the rated voltage of which does not exceed 1 000 V AC or 1 500 V DC.
This third edition cancels and replaces the second edition published in 2005, and its Amendment 1:2013. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
– clarification of scope and object;
– clarification of terms and definitions;
– removal of unnecessary definitions;
– modification of characteristics;
– modification of utilization categories definitions;
– introduction of new markings requirements;
– addition of new requirements for clearances and creepage distances;
– addition of new requirements and tests for mechanical and electrical interlocks;
– clarification of transfer sequences;
– modification of requirements for rated short-time withstand currents;
– modification of new requirements for electromagnetic compatibility;
– clarification of performance requirements for CB type TSE, in alignment with requirements stated in IEC 60947-2;
– addition of new test sequence V: Critical load current performance of equipment with DC ratings.
Appareillage à basse tension - Partie 6-1: Matériels à fonctions multiples - Equipement de transfert de source
L'IEC 60947-6-1:2021 s’applique aux équipements de transfert de source (TSE) destinés à des installations qui assurent la continuité de l’alimentation et permettent la gestion de l’énergie de l’installation, en transférant une charge entre des sources d’alimentation dont la tension assignée ne dépasse pas 1 000 V en courant alternatif ou 1 500 V en courant continu.
Cette troisième édition annule et remplace la deuxième édition parue en 2005, et l'Amendement 1:2013. Cette édition constitue une révision technique.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
– clarification du domaine d’application et de l’objet;
– clarification des termes et définitions;
– retrait des définitions non nécessaires;
– modification des caractéristiques;
– modification des définitions de catégorie d’emploi;
– introduction de nouvelles exigences de marquage;
– ajout de nouvelles exigences relatives aux distances d’isolement et lignes de fuite;
– ajout de nouvelles exigences et de nouveaux essais relatifs aux interverrouillages mécaniques et électriques;
– clarification des séquences de transfert;
– modification des exigences relatives aux courants assignés de courte durée admissibles;
– modification des nouvelles exigences relatives à la compatibilité électromagnétique;
– clarification des exigences relatives aux performances d’un TSE de type CB, en conformité avec les exigences contenues dans l’IEC 60947-2;
– ajout d’une nouvelle séquence d’essais V: fonctionnement au courant critique du matériel ayant des caractéristiques en courant continu.
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Standards Content (Sample)
IEC 60947-6-1 ®
Edition 3.0 2021-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage switchgear and controlgear –
Part 6-1: Multiple function equipment – Transfer switching equipment
Appareillage à basse tension –
Partie 6-1: Matériels à fonctions multiples – Equipement de transfert de source
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IEC 60947-6-1 ®
Edition 3.0 2021-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage switchgear and controlgear –
Part 6-1: Multiple function equipment – Transfer switching equipment
Appareillage à basse tension –
Partie 6-1: Matériels à fonctions multiples – Equipement de transfert de source
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.120.40; 29.130.20 ISBN 978-2-8322-9448-2
– 2 – IEC 60947-6-1:2021 IEC 2021
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 9
3 Terms and definitions . 9
3.1 General . 9
3.2 Alphabetical index of terms . 10
3.3 Transfer switching devices . 10
3.4 Operation of TSE . 12
3.5 Main contact positions . 13
3.6 Symbols and abbreviated terms . 14
4 Classification . 14
5 Characteristics . 15
5.1 Summary of characteristics . 15
5.2 Type and characteristics of equipment . 15
5.3 Rated and limiting values for the main circuit . 16
5.3.1 General . 16
5.3.2 Rated voltages . 16
5.3.3 Rated operational current (I ) . 16
e
5.3.4 Rated frequency . 16
5.3.5 Rated making and breaking capacities . 16
5.3.6 Short-circuit characteristics . 17
5.4 Utilization category . 17
5.5 Control circuits . 18
5.5.1 General . 18
5.5.2 Electro-mechanical devices operating the main circuit . 18
5.5.3 ATS controller. 18
5.6 Auxiliary circuits . 18
6 Product information . 18
6.1 Nature of information . 18
6.2 Marking . 18
6.3 Instructions for installation, operation and maintenance, decommissioning
and dismantling. 20
6.4 Environmental information . 21
7 Normal service, mounting and transport conditions . 22
8 Constructional and performance requirements . 22
8.1 Constructional requirements . 22
8.1.1 General . 22
8.1.2 Materials . 22
8.1.3 Indication of the switching position . 23
8.1.4 Equipment suitable for isolation . 23
8.1.5 Opening and closing of main contacts . 23
8.1.6 Clearances and creepage distances . 23
8.1.7 Provision for protective earthing . 23
8.1.8 Stored charge energy circuit . 23
8.1.9 Stored energy closing . 24
8.1.10 Dedicated enclosures for TSE . 24
8.2 Performance requirements . 24
8.2.1 Operating conditions . 24
8.2.2 Temperature-rise . 25
8.2.3 Dielectric properties . 25
8.2.4 Ability to make, carry, and break under no-load, normal load and
overload conditions . 25
8.2.5 Ability to make and break under short-circuit conditions . 27
8.2.6 Critical load current performance (DC equipment) . 29
8.3 Electromagnetic compatibility (EMC) . 29
8.3.1 General . 29
8.3.2 Immunity . 29
8.3.3 Emission . 30
9 Tests . 30
9.1 Kinds of tests . 30
9.2 Type tests . 30
9.2.1 General test conditions . 30
9.2.2 Test sequences . 30
9.2.3 Test sequence I – General performance characteristics . 33
9.2.4 Test sequence II – Operational performance capability . 39
9.2.5 Test sequence III – Short-circuit performance capability . 44
9.2.6 Test sequence IV – Conditional short-circuit current . 47
9.2.7 Test sequence V – critical load current performance of equipment with a
DC rating . 48
9.2.8 Test sequence VI – EMC tests . 51
9.3 Routine tests. 53
9.4 Environmental tests . 55
Annex A (normative) Assignment of utilization categories based on results of tests . 57
Annex B (informative) Items subject to agreement between manufacturer and user . 58
Bibliography . 59
Figure 1 – Example of operating sequences for TSE with three positions . 21
Figure 2 – Test circuit for connection to source I and source II supplies . 54
Figure 3 – Test circuit for the verification of making and breaking capacities . 55
Table 1 – Utilization categories . 18
Table 2 – Product information . 19
Table 3 – Verification of making and breaking capacity – Conditions for making and
breaking corresponding to the utilization categories . 26
Table 4 – Verification of operational performance – Conditions for making and breaking
corresponding to the utilization categories . 27
Table 5 – Value of the test current for the verification of the ability to operate under
short-circuit conditions . 28
Table 6 – Value of the test current for the verification of the ability to operate under
short-circuit conditions (harmonized table) . 29
Table 7 – Acceptance criteria of immunity test . 30
Table 8 – List of type tests (overall scheme of test sequences) . 31
– 4 – IEC 60947-6-1:2021 IEC 2021
Table 9 – List of type tests to which a derived TSE shall be submitted . 32
Table 10 – Number and duration of operating cycles for the making and breaking
capacity test . 41
Table 11 – Number and rate of operating cycles for the electrical and mechanical
operational performance tests for type A utilization categories . 42
Table 12 – Number and rate of operating cycles for the electrical and mechanical
operational performance tests for type B utilization categories . 42
Table 13 – Temperature-rise limits for terminals and accessible parts . 43
Table 14 – Number of operating cycles corresponding to the critical load current . 50
Table 15 – Test circuit parameters for Table 14 . 50
Table 16 – Test sequence V: Critical load current performance of equipment with a DC
rating . 51
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –
Part 6-1: Multiple function equipment –
Transfer switching equipment
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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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 60947-6-1 has been prepared by sub-committee 121A: Low-
voltage switchgear and controlgear, of IEC technical committee 121: Switchgear and
controlgear and their assemblies for low voltage.
This third edition cancels and replaces the second edition published in 2005, and its
Amendment 1:2013. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
– clarification of scope and object;
– clarification of terms and definitions;
– removal of unnecessary definitions;
– modification of characteristics;
– 6 – IEC 60947-6-1:2021 IEC 2021
– modification of utilization categories definitions;
– introduction of new markings requirements;
– addition of new requirements for clearances and creepage distances;
– addition of new requirements and tests for mechanical and electrical interlocks;
– clarification of transfer sequences;
– modification of requirements for rated short-time withstand currents;
– modification of new requirements for electromagnetic compatibility;
– clarification of performance requirements for CB type TSE, in alignment with requirements
stated in IEC 60947-2;
– addition of new test sequence V: Critical load current performance of equipment with DC
ratings.
The text of this document is based on the following documents:
FDIS Report on voting
121A/403/FDIS 121A/411/RVD
Full information on the voting for the approval of this document 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 the parts in the IEC 60947 series, published under the general title Low-voltage
switchgear and controlgear, can be found on the IEC website.
This document shall be read in conjunction with IEC 60947-1:2020, Low voltage switchgear
and controlgear – Part 1: General rules.
The provisions of the general rules are applicable to IEC 60947-1 where specifically called
for. General rules clauses and subclauses thus applicable as well as tables, figures and
appendices are identified by reference to IEC 60947-1:2020, for example, 1.2.3, Table 4, or
Annex A of IEC 60947-1:2020.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.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates
considered to be useful for the correct
that it contains colours which are
understanding of its contents. Users should therefore print this document using a
colour printer.
INTRODUCTION
The availability of power in low voltage electrical installations is playing an ever increasing
role in modern society. In actual fact, this requirement is a fundamental characteristic for the
creation of economically and functionally efficient installations. A system able to switch a load
from one source to another safely and with minimum disturbance to the load reduces
problems caused by faulty conditions in the normal supply to the minimum.
All these operations, commonly known as “transfer switching”, control the installations and
can be done automatically, remotely or manually.
Therefore, an installation with installed “transfer switching” capability:
– ensures the continuity of production processes;
– provides a backup source of power if the main network is out of service;
– reduces the effect caused by network faults on parts of the installation;
– achieves a good compromise between reliability, simplicity and cost-effectiveness;
– provides the facility manager and managing system with a power source able to supply all
or part of the installation.
Key factors motivating customers to use Transfer Switch Equipment (TSE) include:
– the continuous world growth population, the increasing number of electronic devices and
the new demands of electric vehicles;
– the mediated pressure on climate change with a resulting increase in the cost of energy;
– the evolution of the electricity market with a greater number of alternate energy sources;
– the user’s expectations of better grid reliability, better economic performance, and a desire
to manage their energy.
Stakeholders involved in the management of electricity also have new expectations:
– customers want to reduce the cost of their energy and to have a quality energy supply;
– suppliers want to reinforce confidence to their customers;
– producers expect to optimize their investments;
– governments and regulators are willing to create a competitive and sustainable energy
market.
Today, the performance of Transfer Switching Equipment is defined by TSE manufacturers
and also by this document. Consultants, integrators, facility managers and end users rely on
this document for their power availability needs.
Transfer switching are often realised by implementing a transfer function within the electrical
installation, but this critical function can be inappropriately designed. Using a TSE following
the requirements of this document ensures the safety and the performance of the transfer
function which are necessary for reaching the objectives listed above.
– 8 – IEC 60947-6-1:2021 IEC 2021
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –
Part 6-1: Multiple function equipment –
Transfer switching equipment
1 Scope
This document applies to transfer switching equipment (TSE), to be used in power systems
for ensuring the continuity of the supply and allowing the energy management of the
installation, by transferring a load between power supply sources, the rated voltage of which
does not exceed 1 000 V AC or 1 500 V DC.
It covers:
– manually operated transfer switching equipment (MTSE);
– remotely operated transfer switching equipment (RTSE);
– automatic transfer switching equipment (ATSE), including the controller.
It does not cover:
1) TSE configurations that are either not manufacturer tested and/or not marked according
to this document as a complete transfer switch;
2) auxiliary contacts (for guidance, see IEC 60947-5-1);
3) transfer switches used in explosive atmospheres (for guidance, see IEC 60079 (all
parts));
4) embedded software design (for guidance, see IEC TR 63201);
5) cybersecurity aspects (for guidance, see IEC TS 63208);
6) TSE rated for direct-on-line starting asynchronous motor of design NE and HE, according
to IEC 60034-12:2016 (for guidance, see AC-3e utilisation category according IEC 60947-
4-1:2018);
7) other types of TSE under consideration including closed transition TSE, overlapping
neutral TSE, multi-source TSE (i.e. TSE with more than two sources of supply), stand-
alone ATS controllers, bypass isolation TSE, TSE with load-shedding functions and bus-
tie TSE.
NOTE TSE used for safety services and for emergency escape lighting systems as described in IEC 60364-5-56
are subject to specific rules and/or legal requirements.
The object of this document is to state:
1) the characteristics of the equipment;
2) the conditions of the equipment with respect to:
a) operation for which the equipment is intended;
b) operation and behaviour in case of specified abnormal conditions, for example, short-
circuit;
c) dielectric properties;
3) the tests intended to confirm that these conditions have been met and the methods for
performing these tests;
4) the product information to be provided by the manufacturer.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 60068-2-2:2007, Environmental testing – Part 2-2: Tests – Test B: Dry heat
IEC 60417, Graphical symbols for use on equipment (available at http://www.graphical-
symbols.info/equipment)
IEC 60715:2017, Dimensions of low-voltage switchgear and controlgear – Standardized
mounting on rails for mechanical support of switchgear, controlgear and accessories
IEC 60812, Failure modes and effects analysis (FMEA and FMECA)
IEC 60947 (all parts), Low-voltage switchgear and controlgear
IEC 60947-1:2020, Low-voltage switchgear and controlgear – Part 1: General rules
IEC 60947-2:2016, Low-voltage switchgear and controlgear – Part 2: Circuit-breakers
IEC 60947-2:2016/AMD1:2019
IEC 60947-3:2020, Low-voltage switchgear and controlgear – Part 3: Switches, disconnectors,
switch-disconnectors and fuse-combination units
IEC 60947-4-1:2018, Low-voltage switchgear and controlgear – Part 4-1: Contactors and
motor-starters – Electromechanical contactors and motor-starters
IEC 61000-4-13:2002, Electromagnetic compatibility (EMC) – Part 4-13: Testing and
measurement techniques – Harmonics and interharmonics including mains signalling at a.c.
power port, low frequency immunity tests
IEC 61000-4-13:2002/AMD1:2009
IEC 61000-4-13:2002/AMD2:2015
CISPR 11:2015, Industrial, scientific and medical equipment – Radio-frequency disturbance
characteristics – Limits and methods of measurement
CISPR 11:2015/AMD1:2016
3 Terms and definitions
3.1 General
For the purposes of this document, the terms and definitions given in Clause 3 of IEC 60947-
1:2020, and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• ISO Online browsing platform: available at http://www.iso.org/obp
• IEC Electropedia: available at http://www.electropedia.org/
– 10 – IEC 60947-6-1:2021 IEC 2021
3.2 Alphabetical index of terms
Reference
A
ATS controller . 3.3.9
Automatic transfer switching equipment (ATSE) . 3.3.4
C
Contact transfer time . 3.4.5
Class CB TSE . 3.3.7
Class CC TSE . 3.3.8
Class PC TSE . 3.3.6
Closed transition . 3.4.9
D
Derived transfer switching equipment (derived TSE) . 3.3.5
Dedicated wiring accessories . 3.3.10
F
Frequency supply deviation . 3.4.4
I
Interlocking . 3.4.10
In-phase transfer . 3.4.8
M
Manually operated transfer switching equipment (MTSE) . 3.3.2
Monitored supply deviation . 3.4.2
O
OFF position . 3.5.4
Open transition . 3.4.7
Operating sequence . 3.4.1
Operating transfer time . 3.4.6
P
Position I…………………………………………………………………………………………. 3.5.2
Position II ………………………………………………………………………………… . 3.5.3
R
Remotely operated transfer switching equipment (RTSE) . 3.3.3
S
Switching position . 3.5.1
T
Transfer switching equipment (TSE) . 3.3.1
V
Voltage supply deviation . 3.4.3
3.3 Transfer switching devices
3.3.1
transfer switching equipment
TSE
equipment containing one or more switching devices and associated operating mechanism for
disconnecting load circuits from one supply and connecting to another supply
3.3.2
manually operated transfer switching equipment
MTSE
transfer switching equipment operated manually and non-electrically
3.3.3
remotely operated transfer switching equipment
RTSE
transfer switching equipment that is electrically operated and not self-acting
Note 1 to entry: RTSE can have a feature for local and/or manual operation.
3.3.4
automatic transfer switching equipment
ATSE
self-acting transfer switching equipment, including all necessary sensing inputs, monitoring,
and control logic for transferring operations
Note 1 to entry: ATSE can have a feature for local and/or remote and/or manual operation.
3.3.5
derived transfer switching equipment
derived TSE
TSE based on switching devices that have certain tests required for compliance with
IEC 60947-6-1 as defined in Table 9, covered by IEC 60947-3 for Class PC, IEC 60947-2 or
IEC 60947-6-2 for Class CB, or IEC 60947-4-1 for Class CC
Note 1 to entry: It is not necessary to repeat tests fully covered in the switching devices product standards.
3.3.6
Class PC TSE
transfer switch equipment based on mechanical switching devices, that do not need electrical
power to hold the main contacts open or closed and capable of making, carrying, and
breaking currents under normal circuit conditions including operating overload conditions, and
making and withstanding short-circuit currents
Note 1 to entry: For the purposes of this document, a fuse-combination unit is considered a Class PC device
capable of breaking short-circuit current.
Note 2 to entry: Class PC TSE are also capable of withstanding conditional short-circuit currents.
3.3.7
Class CB TSE
transfer switch equipment based on mechanical switching devices and capable of making,
carrying and breaking currents under normal circuit conditions including operating overload
conditions, and making and breaking short-circuit currents
Note 1 to entry: Class CB TSE for which the manufacturer has assigned a short-time withstand current are also
capable of withstanding short-circuit currents.
3.3.8
Class CC TSE
transfer switch equipment based on mechanical switching devices having only one position of
rest, operating otherwise than by hand, and capable of making, carrying and breaking
currents under normal circuit conditions including operating overload conditions
Note 1 to entry: Class CC TSE are not capable of making or breaking short-circuit currents. They are only
capable of withstanding conditional short-circuit currents.
Note 2 to entry: Class CC TSE is not suitable for isolation.
– 12 – IEC 60947-6-1:2021 IEC 2021
3.3.9
ATS controller
device intended for sensing and monitoring the power supply sources, and controlling the
automatic transfer sequence
Note 1 to entry: ATS controller can be either integral to the ATSE or stand-alone to be associated with an RTSE.
3.3.10
dedicated wiring accessory
prefabricated connection wiring system specifically intended for identified switchgear or
controlgear
Note 1 to entry: A dedicated wiring accessory can be integrated in the switchgear or controlgear or delivered
separately.
Note 2 to entry: A typical dedicated wiring accessory is for example a connection link.
3.4 Operation of TSE
3.4.1
operating sequence
automatic transfer of a load from one supply to another in the event of a monitored supply
deviation and/or other predefined conditions
Note 1 to entry: This definition applies only for ATSE.
3.4.2
monitored supply deviation
variation in the measured power supply characteristics that exceeds predetermined limits
EXAMPLE Abnormal changes in voltage or frequency of the supply are supply deviations.
Note 1 to entry: This definition applies only for ATSE.
3.4.3
voltage supply deviation
change in voltage level from the nominal voltage of the monitored supply
3.4.4
frequency supply deviation
change in frequency from the nominal operating frequency of the monitored supply
3.4.5
contact transfer time
time measured from the mechanical opening of all poles from one set of main contacts of one
power supply to the mechanical closing of any pole of a second set of main contacts on
another power supply, with any adjustable time-delay set to the minimum value
Note 1 to entry: Contact transfer time does not apply to three-position MTSE.
3.4.6
operating transfer time
time measured from the instant when the transfer conditions are fulfilled to the closing of the
main contacts on the other source, with any adjustable time delay set to the minimum value,
transfer condition being typically supply deviations and programmed conditions for ATSE or
remote control commands for RTSE
Note 1 to entry: Operating transfer times from source I to source II and from source II to source I can be
different, and can vary depending on the monitored supply deviation.
Note 2 to entry: Operating transfer time does not apply to MTSE.
3.4.7
open transition
a break before make transfer operation that intentionally breaks the load current from one
source for a period of time prior to making it to the other source
3.4.8
in-phase transfer
control function of an ATSE to only allow an open transition transfer when the two sources are
considered in phase, at the same voltage and frequency
3.4.9
closed transition
a make before break transfer operation that intentionally makes the load current of a second
synchronized source for a short period of time before breaking it from the first source
3.4.10
interlocking
feature(s) that make(s) the state of two mechanisms mutually exclusive, preventing
any of the phases of source I and source II from being connected together
Note 1 to entry: Interlocking prevents the closed position of switching devices to be simultaneously achieved
under all conditions. The state of two mechanisms mutually dependent prevents the change of position of operation
of one mechanism depending on the position of operation of the other.
3.5 Main contact positions
3.5.1
switching position
position of the main contacts defining whether the load terminals are connected to source I or
source II terminals, or not connected
3.5.2
position I
contact position of the equipment when the load terminals are connected to source I terminals
3.5.3
position II
contact position of the equipment when the load terminals are connected to source II
terminals
3.5.4
OFF position
stable contact position of rest of the equipment when the load terminals are connected to
neither source I nor source II terminals
Note 1 to entry: The OFF position may also be marked as the O position.
– 14 – IEC 60947-6-1:2021 IEC 2021
3.6 Symbols and abbreviated terms
EMC Electromagnetic compatibility
FMEA Failure mode effects analysis 9.2.3.2.4
I Current made and broken Table 3
c
I Rated short-circuit making capacity 5.3.6.3
cm
I Rated short-circuit breaking capacity 5.3.6.4
cn
I Rated short-time withstand current 5.3.6.2
cw
I Rated operational current 5.3.3
e
I I Rated conditional short-circuit current 5.3.6.5
q or cc
SCPD Short-circuit protective device
U Rated operational voltage 5.3.2.1
e
U Rated insulation voltage 5.3.2.2
i
U Rated impulse withstand voltage 5.3.2.3
imp
U Power frequency or DC steady-state recovery Table 3
r
voltage
4 Classification
Transfer switching equipment is classified according to:
a) their characteristics:
• Class PC;
• Class CB;
• Class CC;
b) the method of controlling the transfer:
• manually operated switching equipment (MTSE);
• remotely operated switching equipment (RTSE);
• automatic transfer switching equipment (ATSE);
c) the number of main contact positions:
• TSE with two positions (I –II);
• TSE with three positions (I – O –II);
d) their suitability for isolation:
• TSE suitable for isolation in the OFF position;
• TSE not suitable for isolation;
NOTE TSE having only two positions (I – II) and all Class CC TSE are not suitable for isolation.
e) the transition type:
• open transition;
• closed transition (under consideration).
5 Characteristics
5.1 Summary of characteristics
Wherever applicable, the characteristics of the TSE shall be stated as follows:
– type and characteristics of equipment (5.2);
– rated and limiting values for the main circuit (5.3);
– utilization category (5.4);
– control circuits (5.5);
– auxiliary circuits (5.6).
Where the TSE uses IEC 60947 products, the relevant characteristics from those standards
may also be additionally stated.
Specific characteristics subject to agreement between manufacturer and user are listed in
Annex B.
5.2 Type and characteristics of equipment
The following shall be stated:
a) class and transfer control method of the equipment (see Clause 4);
b) number of poles;
c) neutral pole terminal, if applicable, by the letter “N” (see 8.1.8.4 of IEC 60947-1:2020);
d) kind of current (alternating current or direct current or both);
e) in case of alternating current, the number of phases and the rated frequency;
f) number of main contact positions;
g) suitability for isolation;
h) transition type;
i) type of interlock (mechanical, electrical, or electrical-and-mechanical);
NOTE In Canada, Mexico and United States of America open transition transfer switching equipment is required
to use mechanical interlocking.
j) control functions (such as in-phase transfer);
k) contact transfer time;
...
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