IEC 61439-3:2012

IEC 61439-3 ®
Edition 1.0 2012-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Low-voltage switchgear and controlgear assemblies –
Part 3: Distribution boards intended to be operated by ordinary persons (DBO)

Ensembles d'appareillage à basse tension –
Partie 3: Tableaux de répartition destinés à être utilisés par des personnes
ordinaires (DBO)
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IEC 61439-3 ®
Edition 1.0 2012-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Low-voltage switchgear and controlgear assemblies –

Part 3: Distribution boards intended to be operated by ordinary persons (DBO)

Ensembles d'appareillage à basse tension –

Partie 3: Tableaux de répartition destinés à être utilisés par des personnes

ordinaires (DBO)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX R
ICS 29.130.20 ISBN 978-2-88912-922-5

– 2 – 61439-3 © IEC:2012
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Symbols and abbreviations . 6
5 Interface characteristics . 6
6 Information . 7
7 Service conditions . 7
8 Constructional requirements . 8
9 Performance requirements . 9
10 Design verification . 9
11 Routine verification . 12
Annexes . 15
Annex AA (informative) Items subject to agreement between the ASSEMBLY
manufacturer and the user . 16
Bibliography . 20

Figure 101 – Example of temperature rise verification by test of a complete DBO
as in 10.10.2.3.6 . 14

Table 101 – Values of assumed loading . 12
Table 102 – Tightening torque values for the verification of mechanical strength . 13
Table AA.1 – Items subject to agreement between the ASSEMBLY manufacturer and the
user . 16

61439-3 © IEC:2012 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR ASSEMBLIES –

Part 3: Distribution boards intended to be operated
by ordinary persons (DBO)
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
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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
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expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61439-3 has been prepared by subcommittee 17D: Low-voltage
switchgear and controlgear assemblies, of IEC technical committee 17: Switchgear and
controlgear.
This first edition cancels and replaces the first edition of IEC 60439-3 (1990), Amendment 1
(1993) and Amendment 2 (2001). It constitutes a technical revision.
This edition includes the following significant technical changes with respect to IEC 60439-3
(including the amendments):
– alignment with IEC 61439-1:2011.

– 4 – 61439-3 © IEC:2012
The text of this standard is based on the following documents:
FDIS Report on voting
17D/448/FDIS 17D/450/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This standard is to be read in conjunction with IEC 61439-1. The provisions of the general
rules dealt with in IEC 61439-1 (hereinafter referred to as Part 1) are applicable to this
standard where they are specifically cited. When this standard states “addition” “modification”
or “replacement”, the relevant text in Part 1 is to be adapted accordingly.
Subclauses that are numbered with a 101 (102, 103, etc.) suffix are additional to the same
subclause in Part 1.
Tables and figures in this Part 3 that are new are numbered starting with 101.
New annexes in this Part 3 are lettered AA, BB, etc.
The “in some countries” notes regarding differing national practices are contained in the
following subclauses:
3.1.102
6.1
8.2.1
8.5.3
8.6.1
8.8
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 website.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
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.
The contents of the corrigenda of September 2013 and March 2019 have been included in
this copy.
61439-3 © IEC:2012 – 5 –
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR ASSEMBLIES –

Part 3: Distribution boards intended to be operated
by ordinary persons (DBO)
1 Scope
This part of IEC 61439 defines the specific requirements for distribution boards intended to be
operated by ordinary persons (DBO).
DBOs have the following criteria:
– intended to be operated by ordinary persons (e.g. switching operations and replacing
fuse-links), e.g. in domestic (household) applications;
– outgoing circuits contain protective devices, intended to
...