IEC TR 61439-0:2022
(Main)Low-voltage switchgear and controlgear assemblies- Part 0: Guidance to specifying assemblies
Low-voltage switchgear and controlgear assemblies- Part 0: Guidance to specifying assemblies
IEC TR 61439-0:2022 standards for low-voltage switchgear and controlgear assemblies, there are system and application details that are specified by the specifier to enable the manufacturer to produce an assembly that meets the needs and expectations of the specifier.
IEC/TR 61439-0:2022, identifies from the specifier’s perspective those functions and characteristics that are defined when specifying assemblies. It provides:
an explanation of the assembly characteristics and options within the IEC 61439 series;
a guidance on how to select the appropriate options and define characteristics so as to meet specific application needs; and
an assistance in the specification of assemblies. References within this document to the interface characteristics of an assembly and the requirements with which they will comply assume that the assembly is designed, manufactured, and verified in accordance with the relevant part of the IEC 61439 series.
This third edition cancels and replaces the second edition published in 2013. It constitutes a technical revision.
This third edition includes the following significant technical changes with respect to the previous edition:
alignment with IEC 61439-1:2020;
addition of new content in Clause 13 regarding current ratings;
addition of a new subclause 12.8.1 detailing the fundamentals of the forms of internal separation;
alignment of Annex B with Annex AA of 61439-2:2020;
removal of the annexes detailing items subject to agreement between specifier and manufacturer for all product parts as not all of them can always be up to date
Ensembles d'appareillage à basse tension - Partie 0: Recommandations pour la spécification d’ensembles
IEC TR 61439-0:2022 la série de normes IEC 61439 couvrant les ensembles d’appareillage à basse tension, certains détails de système et d’application sont spécifiés par le prescripteur afin de permettre au constructeur de produire un ensemble qui satisfait aux besoins et aux attentes du prescripteur.
L’IEC 61439-0:2022, identifie du point de vue du prescripteur les fonctions et les caractéristiques qui sont définies lors de la spécification des ensembles. Elle fournit:
une explication des caractéristiques et des options contenues dans la série IEC 61439;
des recommandations relatives à la manière de choisir les options appropriées et de définir des caractéristiques de manière à satisfaire aux besoins spécifiques de l’application; et
une aide à la spécification des ensembles. Les références faites dans le présent document aux caractéristiques d’interface d’un ensemble et aux exigences auxquelles elles sont conformes partent du principe que l’ensemble est conçu, construit et vérifié conformément à la partie pertinente de la série IEC 61439.
Cette troisième édition annule et remplace la deuxième édition parue en 2013. Cette édition constitue une révision technique.
Cette troisième édition inclut les modifications techniques majeures suivantes par rapport à l’édition précédente:
alignement sur l’IEC 61439-1:2020;
ajout d’un nouveau contenu à l’Article 13 concernant les caractéristiques assignées de courant;
ajout d’un nouveau paragraphe 12.8.1 décrivant les principes fondamentaux des formes de séparation interne;
alignement de l’Annexe B sur l’Annexe AA de l’IEC 61439-2:2020;
suppression des annexes décrivant les sujets soumis à accord entre le prescripteur et le constructeur pour toutes les parties de produit, car elles ne peuvent pas toutes être toujours à jour.
Sestavi nizkonapetostnih stikalnih in krmilnih naprav - 0. del: Navodila za specificiranje sestavov
V standardih IEC TR 61439-0:2022 za sestave nizkonapetostnih stikalnih in krmilnih naprav določevalec določi podrobnosti glede sistema in uporabe, na podlagi česar lahko proizvajalec izdela sestav, ki ustreza potrebam in pričakovanjem določevalca.
Standard IEC/TR 61439-0:2022 opredeljuje funkcije in lastnosti, ki se določijo pri specificiranju sestavov z vidika določevalca. Standard vključuje:
pojasnilo lastnosti sestava in možnosti v okviru skupine standardov IEC 61439;
smernice za izbiro ustreznih možnosti in določitev lastnosti, da bodo ustrezale posameznim potrebam glede uporabe; in
pomoč pri specificiranju sestavov. Sklici na vmesniške lastnosti sestava v tem dokumentu in zahteve, ki jih morajo te lastnosti izpolnjevati, predpostavljajo, da je sestav zasnovan, proizveden in preverjen v skladu z ustreznim delom skupine standardov IEC 61439.
Tretja izdaja razveljavlja in nadomešča drugo izdajo, objavljeno leta 2013. Ta izdaja je tehnično popravljena izdaja.
Ta tretja izdaja vključuje naslednje znatne tehnične spremembe glede na prejšnjo izdajo:
uskladitev s standardom IEC 61439-1:2020;
dodana nova vsebina v točki 13 glede trenutnih nazivnih tokov;
dodana je nova podtočka 12.8.1, ki podrobno določa temelje oblik notranjega ločevanja;
uskladitev dodatka B z dodatkom AA standarda 61439-2:2020;
odstranjeni so dodatki, ki podrobno določajo elemente, ki so predmet dogovora med določevalcem in proizvajalcem, za vse dele izdelkov, saj vsi ne morejo biti ažurirani.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2023
Sestavi nizkonapetostnih stikalnih in krmilnih naprav - 0. del: Navodila za
specificiranje sestavov
Low-voltage switchgear and controlgear assemblies- Part 0: Guidance to specifying
assemblies
Ensembles d'appareillage à basse tension - Partie 0: Recommandations pour la
spécification d’ensembles
Ta slovenski standard je istoveten z: IEC TR 61439-0:2022
ICS:
29.130.20 Nizkonapetostne stikalne in Low voltage switchgear and
krmilne naprave controlgear
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
IEC TR 61439-0 ®
Edition 3.0 2022-07
TECHNICAL
REPORT
RAPPORT
TECHNIQUE
Low-voltage switchgear and controlgear assemblies –
Part 0: Guidance to specifying assemblies
Ensembles d’appareillage à basse tension –
Partie 0: Recommandations pour la spécification d’ensembles
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.130.20 ISBN 978-2-8322-4027-4
– 2 – IEC TR 61439-0:2022 © IEC 2022
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 10
2 Normative references . 10
3 Terms and definitions . 11
4 Application of assemblies within the IEC 61439 series . 11
4.1 General . 11
4.2 Assembly design and verification . 11
4.3 Service conditions and interface characteristics . 13
4.4 Application design . 13
5 Electrical system . 13
5.1 General . 13
5.2 Earthing system . 13
5.3 Nominal voltage . 14
5.4 Transient overvoltages . 14
5.5 Unusual voltage transients, temporary overvoltages . 16
5.6 Rated frequency f (Hz) . 16
n
5.7 Additional on-site testing requirements: wiring, operational performance and
function . 17
6 Short-circuit withstand capability . 17
6.1 General . 17
6.2 Prospective short-circuit current at supply terminals I (kA) . 18
cp
6.3 Prospective short-circuit current in the neutral . 19
6.4 Prospective short-circuit current in the protective circuit . 19
6.5 Short-circuit protective device (SCPD) . 19
6.6 Coordination of short-circuit protective devices including external short-
circuit protective device details . 20
6.7 Data associated with loads likely to contribute to the short-circuit current . 21
6.8 Multiple supplies . 21
7 Protection of persons against electric shock . 21
7.1 General . 21
7.2 Basic protection (protection against direct contact) . 21
7.2.1 General . 21
7.2.2 Basic insulation provided by insulating material . 22
7.2.3 Basic insulation by barriers or enclosures . 22
7.3 Fault protection (protection against indirect contact) . 22
7.3.1 General . 22
7.3.2 Requirements for the protective conductor to facilitate automatic
disconnection of the supply . 23
7.3.3 Electrical separation . 24
7.3.4 Class II protection (double or reinforced insulation) . 24
8 Installation environment . 24
8.1 General . 24
8.2 Location type . 24
8.3 Protection against access to hazardous parts, ingress of solid foreign bodies
and ingress of water (IP code) . 25
8.4 External mechanical impact (IK code) . 28
8.5 Resistance to radiation . 29
8.5.1 General . 29
8.5.2 Solar irradiance . 29
8.5.3 Ultraviolet (UV) radiation . 29
8.6 Resistance to corrosion . 29
8.7 Ambient air temperature . 30
8.8 Maximum relative humidity . 30
8.9 Pollution degree . 31
8.10 Altitude . 32
8.11 Electromagnetic compatibility (EMC) . 32
8.12 Special service conditions . 33
8.12.1 General . 33
8.12.2 Climatic conditions . 34
8.12.3 Protection against ingress of solid foreign bodies and ingress of water
(IP code) . 34
8.12.4 Shock, vibration, seismic occurrence and external mechanical impact
(IK code) . 34
8.12.5 Fire and explosion hazards . 34
8.12.6 Exceptional overvoltages . 34
8.12.7 Polluted atmospheres . 35
8.12.8 EMC environment . 35
9 Installation method . 35
9.1 General . 35
9.2 Assembly type . 35
9.3 Portability . 36
9.4 Maximum overall dimensions and weight . 36
9.5 External conductor type(s) . 36
9.6 Direction(s) of external conductors . 37
9.7 External conductor material . 37
9.8 External line conductor, cross sections, and terminations . 37
9.9 External PE, N, PEN, PEM, PEL conductors’ cross sections, and
terminations . 37
9.10 Special terminal identification requirements . 38
10 Storage and handling. 38
10.1 General . 38
10.2 Maximum dimensions and weight of transport units . 38
10.3 Methods of transport (e.g. forklift, crane) . 38
10.4 Environmental conditions different from the service conditions . 39
10.5 Packing details . 39
11 Operating arrangements . 39
11.1 General . 39
11.2 Access to manually operated devices . 39
12 Maintenance and upgrade capabilities . 40
12.1 General . 40
12.2 Requirements related to accessibility for inspection and similar operations . 40
12.3 Requirements related to accessibility for maintenance in service by
authorized persons . 41
12.4 Requirements related to extension under voltage . 41
– 4 – IEC TR 61439-0:2022 © IEC 2022
12.5 Protection against direct contact with hazardous live internal parts during
maintenance or upgrade . 41
12.6 Method of functional unit connection . 42
12.7 Operating and maintenance gangways within an assembly . 42
12.8 Internal separation (only relevant for assemblies in accordance with
IEC 61439-2) . 42
12.8.1 Fundamentals of separation . 42
12.8.2 Considerations when determining a form of separation . 43
12.8.3 Selecting the most appropriate form of separation . 44
13 Current carrying capability . 46
13.1 General . 46
13.2 Rated current of the assembly I (A) (maximum current allowable) . 46
nA
13.3 Loading of outgoing circuits within an assembly . 47
13.4 Ratio of cross section of the neutral conductor to line conductors . 48
13.4.1 General . 48
13.4.2 Line conductors up to and including 16 mm . 48
13.4.3 Line conductors above 16 mm . 48
14 Assembly design and routine verification processes . 49
14.1 Design verification . 49
14.1.1 Object . 49
14.1.2 Methods . 49
14.1.3 Records . 50
14.2 Routine verification . 50
14.2.1 General . 50
14.2.2 Records . 50
Annex A (informative) Cross section of copper cables suitable for connection to
terminals for external cables . 51
Annex B (informative) Forms of internal separation (see 12.8) . 52
Annex C (informative) Specification template for assemblies . 58
Annex D (informative) Optional information . 62
D.1 General . 62
D.2 Electrical conditions . 63
D.2.1 Internal arc-fault considerations . 63
D.2.2 Insulated busbars . 64
Annex E (informative) List of notes concerning certain countries . 65
Bibliography . 66
Figure 1 – Required rated impulse withstand voltage . 16
Figure 2 – Examples of separation included in IEC 61439-2 . 45
Figure B.1 – Symbols used in Figure B.2, Figure B.3 and Figure B.4 . 53
Figure B.2 – Form 1 and Form 2 . 55
Figure B.3 – Form 3 . 56
Figure B.4 – Form 4 . 57
Table 1 – IP codes, first numeral . 26
Table 2 – IP codes, second numeral . 27
Table 3 – IP codes, additional letter (optional) . 28
Table 4 – Assemblies and application ratings . 48
Table A.1 – Cross section of copper cables suitable for connection to terminals for
external cables . 51
Table B.1 – Forms of internal separation. 52
Table C.1 – Example of items typically subject to agreement between the assembly
manufacturer and the user . 58
Table D.1 – Examples of optional items subject to agreement between the assembly
manufacturer and the specifier . 62
– 6 – IEC TR 61439-0:2022 © IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR ASSEMBLIES –
Part 0: Guidance to specifying assemblies
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.
IEC TR 61439-0 has been prepared by subcommittee 121B: Low-voltage switchgear and
controlgear assemblies, of IEC technical committee 121: Switchgear and controlgear and their
assemblies for low voltage. It is a Technical Report.
This third edition cancels and replaces the second edition published in 2013. It constitutes a
technical revision.
This third edition includes the following significant technical changes with respect to the
previous edition:
a) alignment with IEC 61439-1:2020;
b) addition of new content in Clause 13 regarding current ratings;
c) addition of a new subclause 12.8.1 detailing the fundamentals of the forms of internal
separation;
d) alignment of Annex B with Annex AA of 61439-2:2020;
e) removal of the annexes detailing items subject to agreement between specifier and
manufacturer for all product parts as not all of them can always be up to date
The text of this Technical Report is based on the following documents:
Draft Report on voting
121B/126/DTR 121B/152/RVDTR
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Technical Report is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
The reader’s attention is drawn to the fact that Annex E lists all of the “in-some-country” clauses
on differing practices of a less permanent nature relating to the subject of this document.
A list of all parts of the IEC 61439 series, under the general title Low-voltage switchgear and
controlgear assemblies, can be found on the IEC web site.
The committee has decided that the contents of this publication will remain unchanged until the
stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to
the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 8 – IEC TR 61439-0:2022 © IEC 2022
INTRODUCTION
Low-voltage assemblies form an integral part of most electrical distribution networks. In their
application they have two prime functions:
– to safely control and distribute electrical energy; and
– to safely isolate sections of faulted networks.
Whilst these two functions place very different demands on the assembly, an assembly has to
be capable of performing both these functions throughout its expected service life. Controlling
and distributing electrical energy is the assembly’s routine ongoing duty. The second function,
fault management, is a very rare occurrence within a well-managed and maintained system.
Some assemblies will never be called upon to manage a fault, but if a fault does occur, it can
place immense thermal and mechanical stresses on the assembly in an instant. Any ageing or
deterioration of the assembly should be limited such that its safety function is not impaired.
Due to the nature of the application, if there are weaknesses in the design or application of an
assembly, it is possible they will not be identified until years after the assembly was installed.
In order to avoid latent issues, and to ensure that assemblies are suitable for their application,
they will be designed and verified to meet the exacting requirements defined in the IEC 61439
series of standards. However, as the IEC 61439 series covers a wide range of applications, and
some applications can be partially outside the scope of the standard, it is equally important that
assemblies are correctly specified. Where options are given in the IEC 61439 series, the most
suitable for the application will be selected; where the requirements are outside the scope of
the standards, detailed requirements will be agreed between the specifier and manufacturer.
This document identifies the significance of each characteristic to be considered when
specifying an assembly and provides the specifier with guidance on defining a suitable
assembly for their application.
For the purposes of this document, the specifier is the party who specifies or selects the
assembly characteristics. The specifier may be the same party as the one who will use and
operate the assembly, or someone acting on their behalf. The aim of this document is to provide
the specifier with guidance on the specification that should be provided in order to obtain an
assembly with the required performance and at optimised costs.
Throughout this document, the term “assembly” is used for a low-voltage switchgear and
controlgear assembly. The term “manufacturer” refers to the assembly manufacturer unless
specifically indicated otherwise.
The term “line conductor” is used in many places throughout this document. Previously the
terminology was phase conductors.
This document is focussed on the specifier, that is, the person or organization providing the
specification for the assembly. It is assumed the specifier is acting on behalf of the user.
The purpose of the IEC 61439 series of standards is to harmonize, as far as practicable, all the
general rules and requirements that apply to assemblies. The series further seeks, in order to
obtain uniformity of requirements for assemblies, consistency in the verification of assemblies
and to avoid the need for verification to other standards.
All the requirements for the various assemblies that can be considered as general, together
with specific subjects dedicated to performances and application, for example temperature rise,
short-circuit, dielectric properties, have therefore been gathered in IEC 61439-1 as general
rules. For each type of assembly only two main standards are necessary to determine all
requirements and the corresponding methods of verification:
1) the standard giving the general rules designated “IEC 61439-1”, and
2) the specific product part of the IEC 61439 series, hereinafter referred to as the relevant
product part of the IEC 61439 series.
The IEC 61439 series of standards encompasses assemblies for a wide variety of uses, some
of which have specific needs as imposed by their particular application. In order to clearly define
these specific needs, relevant product parts of the IEC 61439 series focussed on a particular
type of application have been (or are being) developed. These are identified as IEC 61439-2,
IEC 61439-3, and so on (for a list of all parts of the IEC 61439 series, refer to the IEC web site).
Each relevant product part of the IEC 61439 series with reference to IEC 61439-1, the general
rules, as appropriate, specifies the characteristics and performance required by an assembly
within its defined scope of application. Each relevant product part of the IEC 61439 series
includes, as an annex, a template for “items subject to agreement between the assembly
manufacturer and the specifier” to facilitate the specifying of an assembly.
General characteristics of all types of assemblies are considered in this document. Details
which are applicable to each type of assembly can be determined by reference to the
specification schedule in the relevant product part of the IEC 61439 series.
Within this document, reference to IEC 61439 means the current edition of the IEC 61439 series
of standards, including:
• IEC 61439-1, Low-voltage switchgear and controlgear assemblies – Part 1: General rules
• IEC 61439-2, Low-voltage switchgear and controlgear assemblies – Part 2: Power
switchgear and controlgear assemblies
• IEC 61439-3, Low-voltage switchgear and controlgear assemblies – Part 3: Distribution
boards intended to be operated by ordinary persons (DBO)
• IEC 61439-4, Low-voltage switchgear and controlgear assemblies – Part 4: Particular
requirements for assemblies for construction sites (ACS)
• IEC 61439-5, Low-voltage switchgear and controlgear assemblies – Part 5: Assemblies for
power distribution in public networks
• IEC 61439-6, Low-voltage switchgear and controlgear assemblies – Part 6: Busbar trunking
systems (busways)
• IEC 61439-7, Low-voltage switchgear and controlgear assemblies – Part 7: Assemblies for
specific applications such as marinas, camping sites, market squares, electric vehicles
charging stations
Refer to the IEC web site for the latest edition of each product part of the IEC 61439 series and
additional product part of the IEC 61439 series published for other specific applications.
NOTE Each product part of the IEC 61439 series is related to the appropriate edition of IEC 61439-1, as listed in
the product part, and the corresponding edition of IEC TR 61439-0.
A reference to “general rules” means a reference to IEC 61439-1:2020.
A reference to “product standard” means the relevant part or parts of the IEC standard for the
components used in the assembly (e.g. IEC 60947-2 for circuit-breakers).
– 10 – IEC TR 61439-0:2022 © IEC 2022
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR ASSEMBLIES –
Part 0: Guidance to specifying assemblies
1 Scope
Within the IEC 61439 series of standards for low-voltage switchgear and controlgear
assemblies, there are system and application details that are specified by the specifier to enable
the manufacturer to produce an assembly that meets the needs and expectations of the specifier.
This part of IEC 61439, which is a technical report, identifies from the specifier’s perspective
those functions and characteristics that are defined when specifying assemblies. It provides:
– an explanation of the assembly characteristics and options within the IEC 61439 series;
– a guidance on how to select the appropriate options and define characteristics so as to meet
specific application needs; and
– an assistance in the specification of assemblies.
References within this document to the interface characteristics of an assembly and the
requirements with which they will comply assume that the assembly is designed, manufactured,
and verified in accordance with the relevant part of the IEC 61439 series.
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 61439 (all parts), Low-voltage switchgear and controlgear assemblies
IEC 61439-1:2020, Low-voltage switchgear and controlgear assemblies – Part 1: General rules
IEC 61439-2:2020, Low-voltage switchgear and controlgear assemblies – Part 2: Power
switchgear and controlgear assemblies
IEC 61439-3, Low-voltage switchgear and controlgear assemblies – Part 3: Distribution boards
intended to be operated by ordinary persons (DBO)
IEC 61439-4, Low-voltage switchgear and controlgear assemblies – Part 4: Particular
requirements for assemblies for construction sites (ACS)
IEC 61439-5, Low-voltage switchgear and controlgear assemblies – Part 5: Assemblies for
power distribution in public networks
IEC 61439-6, Low-voltage switchgear and controlgear assemblies – Part 6: Busbar trunking
systems (busways)
IEC 61439-7, Low-voltage switchgear and controlgear assemblies – Part 7: Assemblies for
specific applications such as marinas, camping sites, market squares, electric vehicle charging
stations
3 Terms and definitions
For the purposes of this document, the terms and definitions given in the IEC 61439 series
apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
4 Application of assemblies within the IEC 61439 series
4.1 General
Assemblies manufactured in accordance with the relevant product part of the IEC 61439 series
are suitable for installation in the majority of operating environments. Many of the
characteristics of assemblies are fully defined within the standard and do not require further
consideration by the specifier. In some instances, there can be a default condition specified
within the standard and a range of other identified alternative options, from which the specifier
can choose to suit the application. For other characteristics, the specifier can be required to
choose from a list of options within the standard.
Specifiers are cautioned against over-specifying their requirements; it may not lead to a more
appropriate assembly for their application. More onerous requirements for one criterion usually
have a negative impact on others. For example, an outdoor assembly being specified to comply
with IP66 of IEC 60529, when a lower IP degree, for example IP33, will suffice, can:
– increase temperatures within the assembly due to the lack of ventilation with the effect that
the insulation ages more quickly;
– increase the risk of condensation causing tracking due to there being no ventilation and
therefore no air exchange with the environment outside of the assembly; and
– make the assembly larger and more expensive due to the need to manage the lack of
ventilation.
If special and exceptionally onerous conditions are likely to exist, these conditions should be
identified by the specifier. Examples of these onerous conditions include high ultraviolet (UV)
radiation applications, conditions of high particulates/pollutants, more stringent short-circuit
conditions, special fault protection, special protection due to risk of fire, internal arc-faults,
explosions, burns, etc.
In some instances, the specifier can wish to seek the advice of experts in order to identify their
requirements correctly, for example the cross section of the neutral conductor considering the
system harmonics.
Annex C is typical of the items to be agreed between the specifier and manufacturer when
specifying an assembly. The equivalent annex for each product can be found in the relevant
part of the IEC 61439 series. The specifier should complete the appropriate annex when
defining the interface characteristics for the assembly for their particular application. An
explanation of each interface characteristic is given in Clause 5 to Clause 14 inclusive.
Annex D provides guidance on optional information that a specifier may require for their specific
application.
4.2 Assembly design and verification
An assembly is intended to be used within an electrical installation of defined characteristics.
The assembly can be designed and verified with a specific set of application criteria, to suit a
– 12 – IEC TR 61439-0:2022 © IEC 2022
particular use, or more usually, it can be designed and verified to meet typical application
criteria that make it usable in a range of common applications.
The configuration for a particular specifier application of an assembly usually requires four main
steps:
a) Specification of the requirements and functions particular to the application. The specifier
should complete the table given in Annex C of the relevant product part of the IEC 61439
series.
b) The manufacturer derives the necessary interface characteristics and design of the
assembly to meet the specification. The design will generally be based on the
manufacturer’s previously developed assembly arrangements, characteristics and
functions.
c) For assemblies or parts of assemblies where the design is not previously proven, design
verification is carried out by the manufacturer.
d) Routine verification, carried out on each assembly by the manufacturer.
It is essential that the specifier always insists upon assemblies that are fully verified in
accordance with the appropriate product part of the IEC 61439 series. The nature of the
application is such that deficiencies in an assembly design may not be initially apparent or
readily identified from a cursory examination. For example:
1) The complex thermal effects within an assembly cannot be determined without formal
verification (test, comparison or assessment). Operating components, particularly
insulation, within an assembly at temperatures higher than intended may not cause an
immediate failure but accelerated ageing of insulation can cause a premature failure.
2) Short-circuit protective devices operate rarely during the lifetime of the assembly to interrupt
a fault. When some types of short-circuit protective devices interrupt a fault, they emit a hot
ionized gas which can bridge clearances and/or reduce creepage distances and cause a
flashover within the assembly. There can also be sudden build-up of gas pressure within
the assembly that forces doors and covers to open, possibly endangering anyone in close
proximity.
3) On the rare occasions that a short-circuit occurs, there are complex magnetic effects
associated with high short-circuit currents. These impose substantial mechanical loads on
conductor supports. The forces on the supports are affected by the shape of the conductors,
bends in the conductors, proximity of conductors to each other and ferrous metalwork, phase
relationships between the current in different conductors, and transient effects. All these
effects are very complex and therefore difficult to determine. If not correctly addressed,
conductors can pull together and create an internal arc-fault, or earthed steel housings or
structural supports can be pulled onto live busbar or connections, resulting in assembly
failure.
4) Voltage surges can occur due to switching, lightning and similar. Particularly those
associated with lightning are random occurrences. If and when they do occur, the assembly
has to offer sufficient tolerance (impulse voltage withstand) to the transient overvoltages or
a flashover will occur.
NOTE Surge protective devices can also be required to limit voltage surges. See installation rules for further
details.
5) Corrosion takes time, possibly years. If sufficient protection is not offered, particularly
corrosion protection of parts made of ferrous material, the life of the assembly can be
reduced, and safety compromised, by, for example, reduced mechanical properties of
mounting plates and/or busbar support systems, and reduced earth continuity between
different constructional parts.
6) The ageing of insulating materials is mainly a function of temperature and time, but different
insulating materials age at dramatically different rates for given operating conditions. When
insulating materials age their mechanical, and in some instances electrical properties,
degrade and can cause failures.
The issues listed above, and others, are avoided by using completely verified assemblies. In
some instances, with suitable design margins, the IEC 61439 series permits the verification to
be undertaken by assessment or comparison to a reference design. Where the performance is
less predictable the standard insists on testing as the means of design verification.
For further information on the design and routine verification carried out by the manufacturer,
see Clause 14.
4.3 Service conditions and interface characteristics
The characteristics of the assembly should be compatible with the ratings of the circuits to
which it is connected and the installation conditions.
Where no specification is provided, information given in the manufacturer's documentation may
take the place of an agreement between the manufacturer and the specifier.
It is assumed that the specifier will provide an electrical single line diagram, or equivalent, to
define the incoming and outgoing circuit arrangements, prospective short-circuit current at the
incoming terminals, loads, external conductors, and selected interface characteristics that are
required for the application of a specific assembly.
4.4 Application design
Once the requirements and functions particular to the application have been specified, the
manufacturer is responsible for the design of the assembly, so that it complies with the relevant
product part of the IEC 61439 series. From the information provided by the specifier, the
manufacturer will derive additional assembly characteristics necessary to provide an assembly
that fulfils the application requirements stated. Where the specifier does not indicate particular
requirements, the manufacturer may adopt their usual arrangement or the default arrangement
as given in the relevant product part of the IEC 61439 series.
5 Electrical system
5.1 General
The electrical system determines the electrical characteristics (capabilities, e.g. short-circuit
withstand) an assembly should have in order to perform its required duty safely for the
installation. The characteristics of the assembly should at all times be at least equal to the
requirements of the application and, where essential, they may exceed those offered in the
standard options detailed in the IEC 61439 series.
The specifier should provide an electrical single line diagram and/or any other information
necessary to define their req
...
IEC TR 61439-0 ®
Edition 3.0 2022-07
TECHNICAL
REPORT
RAPPORT
TECHNIQUE
Low-voltage switchgear and controlgear assemblies –
Part 0: Guidance to specifying assemblies
Ensembles d’appareillage à basse tension –
Partie 0: Recommandations pour la spécification d’ensembles
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.
Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.
IEC Secretariat Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.
About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.
IEC publications search - webstore.iec.ch/advsearchform IEC Products & Services Portal - products.iec.ch
The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the
variety of criteria (reference number, text, technical publications previews. With a subscription you will always
committee, …). It also gives information on projects, replaced have access to up to date content tailored to your needs.
and withdrawn publications.
Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished
The world's leading online dictionary on electrotechnology,
Stay up to date on all new IEC publications. Just Published
containing more than 22 300 terminological entries in English
details all new publications released. Available online and
and French, with equivalent terms in 19 additional languages.
once a month by email.
Also known as the International Electrotechnical Vocabulary
(IEV) online.
IEC Customer Service Centre - webstore.iec.ch/csc
If you wish to give us your feedback on this publication or
need further assistance, please contact the Customer Service
Centre: sales@iec.ch.
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.
A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.
Recherche de publications IEC - IEC Products & Services Portal - products.iec.ch
webstore.iec.ch/advsearchform Découvrez notre puissant moteur de recherche et consultez
La recherche avancée permet de trouver des publications IEC gratuitement tous les aperçus des publications. Avec un
en utilisant différents critères (numéro de référence, texte, abonnement, vous aurez toujours accès à un contenu à jour
comité d’études, …). Elle donne aussi des informations sur adapté à vos besoins.
les projets et les publications remplacées ou retirées.
Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished
Le premier dictionnaire d'électrotechnologie en ligne au
Restez informé sur les nouvelles publications IEC. Just
monde, avec plus de 22 300 articles terminologiques en
Published détaille les nouvelles publications parues.
anglais et en français, ainsi que les termes équivalents dans
Disponible en ligne et une fois par mois par email.
19 langues additionnelles. Egalement appelé Vocabulaire
Electrotechnique International (IEV) en ligne.
Service Clients - webstore.iec.ch/csc
Si vous désirez nous donner des commentaires sur cette
publication ou si vous avez des questions contactez-nous:
sales@iec.ch.
IEC TR 61439-0 ®
Edition 3.0 2022-07
TECHNICAL
REPORT
RAPPORT
TECHNIQUE
Low-voltage switchgear and controlgear assemblies –
Part 0: Guidance to specifying assemblies
Ensembles d’appareillage à basse tension –
Partie 0: Recommandations pour la spécification d’ensembles
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.130.20 ISBN 978-2-8322-4027-4
– 2 – IEC TR 61439-0:2022 © IEC 2022
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 10
2 Normative references . 10
3 Terms and definitions . 11
4 Application of assemblies within the IEC 61439 series . 11
4.1 General . 11
4.2 Assembly design and verification . 11
4.3 Service conditions and interface characteristics . 13
4.4 Application design . 13
5 Electrical system . 13
5.1 General . 13
5.2 Earthing system . 13
5.3 Nominal voltage . 14
5.4 Transient overvoltages . 14
5.5 Unusual voltage transients, temporary overvoltages . 16
5.6 Rated frequency f (Hz) . 16
n
5.7 Additional on-site testing requirements: wiring, operational performance and
function . 17
6 Short-circuit withstand capability . 17
6.1 General . 17
6.2 Prospective short-circuit current at supply terminals I (kA) . 18
cp
6.3 Prospective short-circuit current in the neutral . 19
6.4 Prospective short-circuit current in the protective circuit . 19
6.5 Short-circuit protective device (SCPD) . 19
6.6 Coordination of short-circuit protective devices including external short-
circuit protective device details . 20
6.7 Data associated with loads likely to contribute to the short-circuit current . 21
6.8 Multiple supplies . 21
7 Protection of persons against electric shock . 21
7.1 General . 21
7.2 Basic protection (protection against direct contact) . 21
7.2.1 General . 21
7.2.2 Basic insulation provided by insulating material . 22
7.2.3 Basic insulation by barriers or enclosures . 22
7.3 Fault protection (protection against indirect contact) . 22
7.3.1 General . 22
7.3.2 Requirements for the protective conductor to facilitate automatic
disconnection of the supply . 23
7.3.3 Electrical separation . 24
7.3.4 Class II protection (double or reinforced insulation) . 24
8 Installation environment . 24
8.1 General . 24
8.2 Location type . 24
8.3 Protection against access to hazardous parts, ingress of solid foreign bodies
and ingress of water (IP code) . 25
8.4 External mechanical impact (IK code) . 28
8.5 Resistance to radiation . 29
8.5.1 General . 29
8.5.2 Solar irradiance . 29
8.5.3 Ultraviolet (UV) radiation . 29
8.6 Resistance to corrosion . 29
8.7 Ambient air temperature . 30
8.8 Maximum relative humidity . 30
8.9 Pollution degree . 31
8.10 Altitude . 32
8.11 Electromagnetic compatibility (EMC) . 32
8.12 Special service conditions . 33
8.12.1 General . 33
8.12.2 Climatic conditions . 34
8.12.3 Protection against ingress of solid foreign bodies and ingress of water
(IP code) . 34
8.12.4 Shock, vibration, seismic occurrence and external mechanical impact
(IK code) . 34
8.12.5 Fire and explosion hazards . 34
8.12.6 Exceptional overvoltages . 34
8.12.7 Polluted atmospheres . 35
8.12.8 EMC environment . 35
9 Installation method . 35
9.1 General . 35
9.2 Assembly type . 35
9.3 Portability . 36
9.4 Maximum overall dimensions and weight . 36
9.5 External conductor type(s) . 36
9.6 Direction(s) of external conductors . 37
9.7 External conductor material . 37
9.8 External line conductor, cross sections, and terminations . 37
9.9 External PE, N, PEN, PEM, PEL conductors’ cross sections, and
terminations . 37
9.10 Special terminal identification requirements . 38
10 Storage and handling. 38
10.1 General . 38
10.2 Maximum dimensions and weight of transport units . 38
10.3 Methods of transport (e.g. forklift, crane) . 38
10.4 Environmental conditions different from the service conditions . 39
10.5 Packing details . 39
11 Operating arrangements . 39
11.1 General . 39
11.2 Access to manually operated devices . 39
12 Maintenance and upgrade capabilities . 40
12.1 General . 40
12.2 Requirements related to accessibility for inspection and similar operations . 40
12.3 Requirements related to accessibility for maintenance in service by
authorized persons . 41
12.4 Requirements related to extension under voltage . 41
– 4 – IEC TR 61439-0:2022 © IEC 2022
12.5 Protection against direct contact with hazardous live internal parts during
maintenance or upgrade . 41
12.6 Method of functional unit connection . 42
12.7 Operating and maintenance gangways within an assembly . 42
12.8 Internal separation (only relevant for assemblies in accordance with
IEC 61439-2) . 42
12.8.1 Fundamentals of separation . 42
12.8.2 Considerations when determining a form of separation . 43
12.8.3 Selecting the most appropriate form of separation . 44
13 Current carrying capability . 46
13.1 General . 46
13.2 Rated current of the assembly I (A) (maximum current allowable) . 46
nA
13.3 Loading of outgoing circuits within an assembly . 47
13.4 Ratio of cross section of the neutral conductor to line conductors . 48
13.4.1 General . 48
13.4.2 Line conductors up to and including 16 mm . 48
13.4.3 Line conductors above 16 mm . 48
14 Assembly design and routine verification processes . 49
14.1 Design verification . 49
14.1.1 Object . 49
14.1.2 Methods . 49
14.1.3 Records . 50
14.2 Routine verification . 50
14.2.1 General . 50
14.2.2 Records . 50
Annex A (informative) Cross section of copper cables suitable for connection to
terminals for external cables . 51
Annex B (informative) Forms of internal separation (see 12.8) . 52
Annex C (informative) Specification template for assemblies . 58
Annex D (informative) Optional information . 62
D.1 General . 62
D.2 Electrical conditions . 63
D.2.1 Internal arc-fault considerations . 63
D.2.2 Insulated busbars . 64
Annex E (informative) List of notes concerning certain countries . 65
Bibliography . 66
Figure 1 – Required rated impulse withstand voltage . 16
Figure 2 – Examples of separation included in IEC 61439-2 . 45
Figure B.1 – Symbols used in Figure B.2, Figure B.3 and Figure B.4 . 53
Figure B.2 – Form 1 and Form 2 . 55
Figure B.3 – Form 3 . 56
Figure B.4 – Form 4 . 57
Table 1 – IP codes, first numeral . 26
Table 2 – IP codes, second numeral . 27
Table 3 – IP codes, additional letter (optional) . 28
Table 4 – Assemblies and application ratings . 48
Table A.1 – Cross section of copper cables suitable for connection to terminals for
external cables . 51
Table B.1 – Forms of internal separation. 52
Table C.1 – Example of items typically subject to agreement between the assembly
manufacturer and the user . 58
Table D.1 – Examples of optional items subject to agreement between the assembly
manufacturer and the specifier . 62
– 6 – IEC TR 61439-0:2022 © IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR ASSEMBLIES –
Part 0: Guidance to specifying assemblies
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.
IEC TR 61439-0 has been prepared by subcommittee 121B: Low-voltage switchgear and
controlgear assemblies, of IEC technical committee 121: Switchgear and controlgear and their
assemblies for low voltage. It is a Technical Report.
This third edition cancels and replaces the second edition published in 2013. It constitutes a
technical revision.
This third edition includes the following significant technical changes with respect to the
previous edition:
a) alignment with IEC 61439-1:2020;
b) addition of new content in Clause 13 regarding current ratings;
c) addition of a new subclause 12.8.1 detailing the fundamentals of the forms of internal
separation;
d) alignment of Annex B with Annex AA of 61439-2:2020;
e) removal of the annexes detailing items subject to agreement between specifier and
manufacturer for all product parts as not all of them can always be up to date
The text of this Technical Report is based on the following documents:
Draft Report on voting
121B/126/DTR 121B/152/RVDTR
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Technical Report is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
The reader’s attention is drawn to the fact that Annex E lists all of the “in-some-country” clauses
on differing practices of a less permanent nature relating to the subject of this document.
A list of all parts of the IEC 61439 series, under the general title Low-voltage switchgear and
controlgear assemblies, can be found on the IEC web site.
The committee has decided that the contents of this publication will remain unchanged until the
stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to
the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 8 – IEC TR 61439-0:2022 © IEC 2022
INTRODUCTION
Low-voltage assemblies form an integral part of most electrical distribution networks. In their
application they have two prime functions:
– to safely control and distribute electrical energy; and
– to safely isolate sections of faulted networks.
Whilst these two functions place very different demands on the assembly, an assembly has to
be capable of performing both these functions throughout its expected service life. Controlling
and distributing electrical energy is the assembly’s routine ongoing duty. The second function,
fault management, is a very rare occurrence within a well-managed and maintained system.
Some assemblies will never be called upon to manage a fault, but if a fault does occur, it can
place immense thermal and mechanical stresses on the assembly in an instant. Any ageing or
deterioration of the assembly should be limited such that its safety function is not impaired.
Due to the nature of the application, if there are weaknesses in the design or application of an
assembly, it is possible they will not be identified until years after the assembly was installed.
In order to avoid latent issues, and to ensure that assemblies are suitable for their application,
they will be designed and verified to meet the exacting requirements defined in the IEC 61439
series of standards. However, as the IEC 61439 series covers a wide range of applications, and
some applications can be partially outside the scope of the standard, it is equally important that
assemblies are correctly specified. Where options are given in the IEC 61439 series, the most
suitable for the application will be selected; where the requirements are outside the scope of
the standards, detailed requirements will be agreed between the specifier and manufacturer.
This document identifies the significance of each characteristic to be considered when
specifying an assembly and provides the specifier with guidance on defining a suitable
assembly for their application.
For the purposes of this document, the specifier is the party who specifies or selects the
assembly characteristics. The specifier may be the same party as the one who will use and
operate the assembly, or someone acting on their behalf. The aim of this document is to provide
the specifier with guidance on the specification that should be provided in order to obtain an
assembly with the required performance and at optimised costs.
Throughout this document, the term “assembly” is used for a low-voltage switchgear and
controlgear assembly. The term “manufacturer” refers to the assembly manufacturer unless
specifically indicated otherwise.
The term “line conductor” is used in many places throughout this document. Previously the
terminology was phase conductors.
This document is focussed on the specifier, that is, the person or organization providing the
specification for the assembly. It is assumed the specifier is acting on behalf of the user.
The purpose of the IEC 61439 series of standards is to harmonize, as far as practicable, all the
general rules and requirements that apply to assemblies. The series further seeks, in order to
obtain uniformity of requirements for assemblies, consistency in the verification of assemblies
and to avoid the need for verification to other standards.
All the requirements for the various assemblies that can be considered as general, together
with specific subjects dedicated to performances and application, for example temperature rise,
short-circuit, dielectric properties, have therefore been gathered in IEC 61439-1 as general
rules. For each type of assembly only two main standards are necessary to determine all
requirements and the corresponding methods of verification:
1) the standard giving the general rules designated “IEC 61439-1”, and
2) the specific product part of the IEC 61439 series, hereinafter referred to as the relevant
product part of the IEC 61439 series.
The IEC 61439 series of standards encompasses assemblies for a wide variety of uses, some
of which have specific needs as imposed by their particular application. In order to clearly define
these specific needs, relevant product parts of the IEC 61439 series focussed on a particular
type of application have been (or are being) developed. These are identified as IEC 61439-2,
IEC 61439-3, and so on (for a list of all parts of the IEC 61439 series, refer to the IEC web site).
Each relevant product part of the IEC 61439 series with reference to IEC 61439-1, the general
rules, as appropriate, specifies the characteristics and performance required by an assembly
within its defined scope of application. Each relevant product part of the IEC 61439 series
includes, as an annex, a template for “items subject to agreement between the assembly
manufacturer and the specifier” to facilitate the specifying of an assembly.
General characteristics of all types of assemblies are considered in this document. Details
which are applicable to each type of assembly can be determined by reference to the
specification schedule in the relevant product part of the IEC 61439 series.
Within this document, reference to IEC 61439 means the current edition of the IEC 61439 series
of standards, including:
• IEC 61439-1, Low-voltage switchgear and controlgear assemblies – Part 1: General rules
• IEC 61439-2, Low-voltage switchgear and controlgear assemblies – Part 2: Power
switchgear and controlgear assemblies
• IEC 61439-3, Low-voltage switchgear and controlgear assemblies – Part 3: Distribution
boards intended to be operated by ordinary persons (DBO)
• IEC 61439-4, Low-voltage switchgear and controlgear assemblies – Part 4: Particular
requirements for assemblies for construction sites (ACS)
• IEC 61439-5, Low-voltage switchgear and controlgear assemblies – Part 5: Assemblies for
power distribution in public networks
• IEC 61439-6, Low-voltage switchgear and controlgear assemblies – Part 6: Busbar trunking
systems (busways)
• IEC 61439-7, Low-voltage switchgear and controlgear assemblies – Part 7: Assemblies for
specific applications such as marinas, camping sites, market squares, electric vehicles
charging stations
Refer to the IEC web site for the latest edition of each product part of the IEC 61439 series and
additional product part of the IEC 61439 series published for other specific applications.
NOTE Each product part of the IEC 61439 series is related to the appropriate edition of IEC 61439-1, as listed in
the product part, and the corresponding edition of IEC TR 61439-0.
A reference to “general rules” means a reference to IEC 61439-1:2020.
A reference to “product standard” means the relevant part or parts of the IEC standard for the
components used in the assembly (e.g. IEC 60947-2 for circuit-breakers).
– 10 – IEC TR 61439-0:2022 © IEC 2022
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR ASSEMBLIES –
Part 0: Guidance to specifying assemblies
1 Scope
Within the IEC 61439 series of standards for low-voltage switchgear and controlgear
assemblies, there are system and application details that are specified by the specifier to enable
the manufacturer to produce an assembly that meets the needs and expectations of the specifier.
This part of IEC 61439, which is a technical report, identifies from the specifier’s perspective
those functions and characteristics that are defined when specifying assemblies. It provides:
– an explanation of the assembly characteristics and options within the IEC 61439 series;
– a guidance on how to select the appropriate options and define characteristics so as to meet
specific application needs; and
– an assistance in the specification of assemblies.
References within this document to the interface characteristics of an assembly and the
requirements with which they will comply assume that the assembly is designed, manufactured,
and verified in accordance with the relevant part of the IEC 61439 series.
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 61439 (all parts), Low-voltage switchgear and controlgear assemblies
IEC 61439-1:2020, Low-voltage switchgear and controlgear assemblies – Part 1: General rules
IEC 61439-2:2020, Low-voltage switchgear and controlgear assemblies – Part 2: Power
switchgear and controlgear assemblies
IEC 61439-3, Low-voltage switchgear and controlgear assemblies – Part 3: Distribution boards
intended to be operated by ordinary persons (DBO)
IEC 61439-4, Low-voltage switchgear and controlgear assemblies – Part 4: Particular
requirements for assemblies for construction sites (ACS)
IEC 61439-5, Low-voltage switchgear and controlgear assemblies – Part 5: Assemblies for
power distribution in public networks
IEC 61439-6, Low-voltage switchgear and controlgear assemblies – Part 6: Busbar trunking
systems (busways)
IEC 61439-7, Low-voltage switchgear and controlgear assemblies – Part 7: Assemblies for
specific applications such as marinas, camping sites, market squares, electric vehicle charging
stations
3 Terms and definitions
For the purposes of this document, the terms and definitions given in the IEC 61439 series
apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
4 Application of assemblies within the IEC 61439 series
4.1 General
Assemblies manufactured in accordance with the relevant product part of the IEC 61439 series
are suitable for installation in the majority of operating environments. Many of the
characteristics of assemblies are fully defined within the standard and do not require further
consideration by the specifier. In some instances, there can be a default condition specified
within the standard and a range of other identified alternative options, from which the specifier
can choose to suit the application. For other characteristics, the specifier can be required to
choose from a list of options within the standard.
Specifiers are cautioned against over-specifying their requirements; it may not lead to a more
appropriate assembly for their application. More onerous requirements for one criterion usually
have a negative impact on others. For example, an outdoor assembly being specified to comply
with IP66 of IEC 60529, when a lower IP degree, for example IP33, will suffice, can:
– increase temperatures within the assembly due to the lack of ventilation with the effect that
the insulation ages more quickly;
– increase the risk of condensation causing tracking due to there being no ventilation and
therefore no air exchange with the environment outside of the assembly; and
– make the assembly larger and more expensive due to the need to manage the lack of
ventilation.
If special and exceptionally onerous conditions are likely to exist, these conditions should be
identified by the specifier. Examples of these onerous conditions include high ultraviolet (UV)
radiation applications, conditions of high particulates/pollutants, more stringent short-circuit
conditions, special fault protection, special protection due to risk of fire, internal arc-faults,
explosions, burns, etc.
In some instances, the specifier can wish to seek the advice of experts in order to identify their
requirements correctly, for example the cross section of the neutral conductor considering the
system harmonics.
Annex C is typical of the items to be agreed between the specifier and manufacturer when
specifying an assembly. The equivalent annex for each product can be found in the relevant
part of the IEC 61439 series. The specifier should complete the appropriate annex when
defining the interface characteristics for the assembly for their particular application. An
explanation of each interface characteristic is given in Clause 5 to Clause 14 inclusive.
Annex D provides guidance on optional information that a specifier may require for their specific
application.
4.2 Assembly design and verification
An assembly is intended to be used within an electrical installation of defined characteristics.
The assembly can be designed and verified with a specific set of application criteria, to suit a
– 12 – IEC TR 61439-0:2022 © IEC 2022
particular use, or more usually, it can be designed and verified to meet typical application
criteria that make it usable in a range of common applications.
The configuration for a particular specifier application of an assembly usually requires four main
steps:
a) Specification of the requirements and functions particular to the application. The specifier
should complete the table given in Annex C of the relevant product part of the IEC 61439
series.
b) The manufacturer derives the necessary interface characteristics and design of the
assembly to meet the specification. The design will generally be based on the
manufacturer’s previously developed assembly arrangements, characteristics and
functions.
c) For assemblies or parts of assemblies where the design is not previously proven, design
verification is carried out by the manufacturer.
d) Routine verification, carried out on each assembly by the manufacturer.
It is essential that the specifier always insists upon assemblies that are fully verified in
accordance with the appropriate product part of the IEC 61439 series. The nature of the
application is such that deficiencies in an assembly design may not be initially apparent or
readily identified from a cursory examination. For example:
1) The complex thermal effects within an assembly cannot be determined without formal
verification (test, comparison or assessment). Operating components, particularly
insulation, within an assembly at temperatures higher than intended may not cause an
immediate failure but accelerated ageing of insulation can cause a premature failure.
2) Short-circuit protective devices operate rarely during the lifetime of the assembly to interrupt
a fault. When some types of short-circuit protective devices interrupt a fault, they emit a hot
ionized gas which can bridge clearances and/or reduce creepage distances and cause a
flashover within the assembly. There can also be sudden build-up of gas pressure within
the assembly that forces doors and covers to open, possibly endangering anyone in close
proximity.
3) On the rare occasions that a short-circuit occurs, there are complex magnetic effects
associated with high short-circuit currents. These impose substantial mechanical loads on
conductor supports. The forces on the supports are affected by the shape of the conductors,
bends in the conductors, proximity of conductors to each other and ferrous metalwork, phase
relationships between the current in different conductors, and transient effects. All these
effects
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.
Loading comments...