oSIST prEN IEC 61439-3:2022

SLOVENSKI STANDARD
oSIST prEN IEC 61439-3:2022
01-oktober-2022
Sestavi nizkonapetostnih stikalnih in krmilnih naprav - 3. del: Električni
razdelilniki, s katerimi lahko ravnajo nestrokovnjaki (DBO)
Low-voltage switchgear and controlgear assemblies - Part 3: Distribution boards
intended to be operated by ordinary persons (DBO)
Niederspannungs-Schaltgerätekombinationen - Teil 3: Installationsverteiler für die
Bedienung durch Laien (DBO)
Ensembles d'appareillage à basse tension - Partie 3: Tableaux de répartition destinés à
être utilisés par des personnes ordinaires (DBO)
Ta slovenski standard je istoveten z: prEN IEC 61439-3:2022
ICS:
29.130.20 Nizkonapetostne stikalne in Low voltage switchgear and
krmilne naprave controlgear
oSIST prEN IEC 61439-3:2022 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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121B/159/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 61439-3 ED2
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2022-07-15 2022-10-07
SUPERSEDES DOCUMENTS:
121B/139/CD, 121B/158/CC

IEC SC 121B : LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR ASSEMBLIES
SECRETARIAT: SECRETARY:
Germany Mr Jörg Hußmann
OF INTEREST TO THE FOLLOWING COMMITTEES: PROPOSED HORIZONTAL STANDARD:

TC 18,TC 44,TC 64,SC 121A
Other TC/SCs are requested to indicate their interest, if
any, in this CDV to the secretary.
FUNCTIONS CONCERNED:
EMC ENVIRONMENT QUALITY ASSURANCE SAFETY
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft
for Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.

This document is still under study and subject to change. It should not be used for reference purposes.
Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of
which they are aware and to provide supporting documentation.

TITLE:
Low-voltage switchgear and controlgear assemblies - Part 3: Distribution boards intended to
be operated by ordinary persons (DBO)

PROPOSED STABILITY DATE: 2026

NOTE FROM TC/SC OFFICERS:


Copyright © 2022 International Electrotechnical Commission, IEC. All rights reserved. It is permitted to
download this electronic file, to make a copy and to print out the content for the sole purpose of preparing National
Committee positions. You may not copy or "mirror" the file or printed version of the document, or any part of it, for
any other purpose without permission in writing from IEC.

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1 CONTENTS
2 FOREWORD . 4
3 1 Scope . 6
4 2 Normative references . 6
5 3 Terms and definitions . 7
6 3.1 General terms . 7
7 4 Symbols and abbreviations . 8
8 5 Interface characteristics . 8
9 5.1 General . 8
10 5.2.4 Rated impulse withstand voltage (U ) (of the assembly ). 8
imp
11 5.4 Rated diversity factor (RDF) . 8
12 6 Information . 8
13 6.1 Assembly designation marking . 8
14 6.2.2 Instructions for handling, installation, operation and maintenance . 9
15 6.3 Device and/or component identification . 9
16 7 Service conditions . 9
17 7.1.2 Pollution degree . 9
18 8 Constructional requirements . 9
19 8.1.3.2.2 Resistance of insulating materials to normal heat . 9
20 8.2.1 Protection against mechanical impact (IK code) . 9
21 8.2.2 Protection against contact with live parts, ingress of solid foreign bodies and
22 water (IP code) . 9
23 IP 2XC shall be maintained when operating devices e.g. switching and operating
24 test buttons in normal use. The degree of protection can be temporarily
25 reduced when permitted in a product standard for use by ordinary / unskilled
26 persons e.g. IEC 60269-3 for replacing a fuse-link, the degree of protection
27 may temporarily be reduced to IP1X. . 9
28 8.4.2.3 Barriers or enclosures . 9
29 8.5.3 Selection of switching devices and components . 10
30 8.6.1 Main circuits . 10
31 8.8 Terminals for external cables . 10
32 9 Performance requirements . 10
33 9.1.1 General . 10
34 10 Design verification . 10
35 10.2.2.2Severity test A . 10
36 10.2.2.4Results to be obtained . 11
37 10.2.3.2.1 Verification by test . 11
38 10.2.6 Verification of protection against mechanical impact (IK code) . 11
39 10.2.7.1 Verification by test . 12
40 10.10.2.2.3 Functional units . 12
41 10.10.2.3.1General . 13
42 10.10.2.3.6 Verification considering individual functional units
43 separately and the complete assembly . 13
44 10.10.2.3.7 Verification considering individual functional units and the
45 main and distribution busbars separately as well as the complete assembly . 13
46 10.10.3.2Assemblies . 14
47 10.10.4.2.3Results to be obtained . 14
48 10.10.4.3.2Results to be obtained . 14
49 10.11.5.3.3Incoming circuit and main busbars . 14
50 11 Routine verification . 15

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51 Annexes. 18
52 Annex AA (informative) Items subject to agreement between the DBO manufacturer
53 and the user . 19
54 Annex BB (informative) Effects upon a DBO design and related ratings, instructions
55 etc when used in a prosumer’s electrical installation (PEI) . 25
56 Annex CC (informative) . 26
57 Annex DD (informative) List of notes concerning certain countries . 27
58 Bibliography . 40
59
60 UK Figure 101 – Example of temperature rise verification by test of a complete
61 split-load DBO as in 10.10.2.3.6 . 31
62
63 Table 101 – Values of assumed loading . 16
64 Table 102 – Tightening torque values for the verification of mechanical strength . 17
65 Table AA.1 – Items subject to agreement between the DBO manufacturer and the user . 19
66
67

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68 INTERNATIONAL ELECTROTECHNICAL COMMISSION
69 ____________
70
71 LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR ASSEMBLIES –
72
73 Part 3: Distribution boards intended to be operated
74 by ordinary persons (DBO)
75
76 FOREWORD
77 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
78 all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
79 co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
80 in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
81 Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their
82 preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
83 may participate in this preparatory work. International, governmental and non-governmental organizations liaising
84 with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
85 Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
86 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
87 consensus of opinion on the relevant subjects since each technical committee has representation from all
88 interested IEC National Committees.
89 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
90 Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
91 Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
92 misinterpretation by any end user.
93 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
94 transparently to the maximum extent possible in their national and regional publications. Any divergence between
95 any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
96 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
97 assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
98 services carried out by independent certification bodies.
99 6) All users should ensure that they have the latest edition of this publication.
100 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
101 members of its technical committees and IEC National Committees for any personal injury, property damage or
102 other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
103 expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
104 Publications.
105 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
106 indispensable for the correct application of this publication.
107 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
108 rights. IEC shall not be held responsible for identifying any or all such patent rights.
109 International Standard IEC 61439-3 has been prepared by subcommittee 121B: Low-voltage
110 switchgear and controlgear assemblies, of IEC technical committee 121: Switchgear and
111 controlgear and their assemblies for low voltage.
112 This second edition cancels and replaces the first edition published in 2012, corrigendum 1
113 (2013) and corrigendum 2 (2019). It constitutes a technical revision.
114 This edition includes the following significant technical changes with respect to the previous
115 edition:
116 a) XX
117 b) XX
118 c) alignment with the structure of IEC 61439-1, 2020;
119 d) general editorial review.
120 The text of this standard is based on the following documents:
FDIS Report on voting
121B/XXX/FDIS 121B/XXX/RVD

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121
122 Full information on the voting for the approval of this standard can be found in the report on
123 voting indicated in the above table.
124 This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
125 This standard is to be read in conjunction with IEC 61439-1:2020. The provisions of the general
126 rules dealt with in IEC 61439-1 are only applicable to this standard insofar they are specifically
127 cited. When this standard states “addition” “modification” or “replacement”, the relevant text in
128 IEC 61439-1:2020 is to be adapted accordingly.
129 Subclauses that are numbered with a 101 (102, 103, etc.) suffix are additional to the same
130 subclause in Part 1.
131 Tables and figures in this document that are new are numbered starting with 101.
132 New annexes in this document are lettered AA, BB, etc.
133 The reader’s attention is drawn to the fact that Annex DD lists all of the “in some-country”
134 clauses on differing practices of a less permanent nature relating to the subject of this standard.
135 A list of all parts of the IEC 61439 series, under the general title Low-voltage switchgear and
136 controlgear assemblies can be found on the IEC website.
137 The committee has decided that the contents of this publication will remain unchanged until the
138 stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to
139 the specific publication. At this date, the publication will be
140 • reconfirmed,
141 • withdrawn,
142 • replaced by a revised edition, or
143 • amended.
144
145

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146 LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR ASSEMBLIES –
147
148 Part 3: Distribution boards intended to be operated
149 by ordinary persons (DBO)
150
151 1 Scope
152 Clause 1 of IEC 61439-1:2020 is applicable except as follows.
153 Replacement:
154 This part of IEC 61439 defines the specific requirements for distribution boards intended to be
155 operated by ordinary persons (abbreviated DBO throughout this document see 3.1.101) as
156 follows:
157 – assemblies intended to be operated by ordinary persons (e.g. switching operations and
158 replacing fuse-links), e.g. in domestic (household) applications;
159 – assemblies containing outgoing circuits with protective devices intended to be
160 operated by ordinary persons, complying e.g. with IEC 60898-1, IEC 61008,
161 IEC 61009, IEC 62606, IEC 62423 and IEC 60269-3;
162 – assemblies for applications where the nominal voltage to earth does not exceed
163 300 V AC (see table G.1 of Annex G of IEC 61439-1 :2020);
164 – assemblies with a rated current (Inc) of the outgoing circuits not exceeding 125 A and
165 the rated current (I ) not exceeding 250 A;
nA
166 – assemblies intended for use in connection with the generation, transmission,
167 distribution and conversion of electrical energy, and for the control of equipment
168 consuming electrical energy and for associated data processing;
169 – enclosed, stationary assemblies;
170 – assemblies for indoor or outdoor use.
171 DBOs can contain only: protection devices, control / signalling devices, or a combination of
172 devices .e.g. circuit-breakers, WI/Fi router, load shedding relay, energy management,
173 communication devices, lighting control.
174 This standard does not apply to an empty enclosure nor to individual devices and self-contained
175 components, such as circuit-breakers, fuse switches, electronic equipment, etc. which comply
176 with the relevant product standards, it describes the integration of devices and / or self-
177 contained components into a DBO or into an empty enclosure forming a DBO.
178 This standard applies to DBOs designed, manufactured and verified on a one-off basis or fully
179 standardised and manufactured in quantity.
180 DBOs may be assembled outside the factory of the original manufacturer. DBOs may be
181 assembled by the original manufacturer or by an assembly manufacturer.
182 This standard does not apply to the specific types of assemblies covered by other parts of
183 IEC 61439.
184 NOTE Enclosures for electrical accessories for household and similar fixed electrical installations are covered in IEC
185 60670-24
186 2 Normative references
187 The following documents are referred to in the text in such a way that some or all of their content
188 constitutes requirements of this document. For dated references, only the edition cited applies.
189 For undated references, the latest edition of the referenced document (including any
190 amendments) applies.
191 Clause 2 of IEC 61439-1:2020 is applicable in addition to the following.

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192 Addition:
193 IEC 60068-2-75, Environmental testing – Part 2: Tests – Test Eh: Hammer tests
194 IEC 60269-3, Low-voltage fuses – Part 3: Supplementary requirements for fuses for use by
195 unskilled persons (fuses mainly for household and similar applications) – Examples of
196 standardized systems of fuses A to F
197 IEC 60364-8-2, Low-voltage electrical installations - Part 8-2: Prosumer's low-voltage electrical
198 installations
199 IEC 60898-1, Electrical accessories – Circuit-breakers for overcurrent protection for household
200 and similar installations – Part 1: Circuit-breakers for a.c. operation
201 IEC 60669-2-4, Switches for household and similar fixed electrical installations - Part 2-4:
202 Particular requirements - Isolating switches
203 IEC 60947-3, Low-voltage switchgear and controlgear - Part 3: Switches, disconnectors, switch-
204 disconnectors and fuse-combination units
205 IEC 61008 (all parts), Residual current operated circuit-breakers without integral overcurrent
206 protection for household and similar uses (RCCBs)
207 IEC 61009 (all parts), Residual current operated circuit-breakers with integral overcurrent
208 protection for household and similar uses (RCBOs)
209 IEC 61439-1:2020, Low-voltage switchgear and controlgear assemblies – Part 1: General rules
210 IEC 62423:2009, Type F and type B residual current operated circuit-breakers with and without
211 integral overcurrent protection for household and similar uses
212 IEC 62262, Degrees of protection provided by enclosures for electrical equipment against
213 external mechanical impacts (IK code)
214 IEC 62606:2017, General requirements for arc fault detection devices
215 3 Terms and definitions
216 For the purposes of this document, the terms and definitions given in IEC 61439-1:2020 and
217 the following apply.
218 ISO and IEC maintain terminological databases for use in standardization at the following
219 addresses:
220 • IEC Electropedia: available at http://www.electropedia.org/
221 • ISO Online browsing platform: available at http://www.iso.org/obp
222
223 Clause 3 of IEC 61439-1:2020 is applicable except as follows.
224 3.1 General terms
225 Additional terms and definitions:
226 3.1.101
227 distribution board intended to be operated by ordinary persons
228 DBO
229 assembly used to distribute and control electrical energy for all types of electrical supplies and
230 loads, intended for operation by ordinary persons (see 8.4.6.1 IEC 61439-1:2020)
231 Note 1 to entry: Switching operations and replacing fuse-links are examples of operations intended to be carried out
232 by ordinary persons.

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233 Note 2 to entry: This does not preclude the DBO being operated by skilled / instructed persons and also being used
234 in non-domestic installations.
235 4 Symbols and abbreviations
236 Clause 4 of IEC 61439-1:2020 is applicable.
237 5 Interface characteristics
238 Clause 5 of IEC 61439-1:2020 is applicable except as follows.
239 5.1 General
240 Addition:
241 This objective can be achieved through one of two typical processes; the user will either select
242 a catalogue product, the characteristics of which meet the required user needs, or make a
243 specific agreement with the manufacturer.
244 In both cases, the specification schedule according to Annex AA is intended to help the user to
245 provide all data necessary to specify, and to help the manufacturer to characterize the actual
246 DBO. In some cases information declared by the DBO manufacturer may take the place of an
247 agreement.
248 5.2.4 Rated impulse withstand voltage (U ) (of the assembly )
imp
249 Replacement:
250 The rated impulse withstand voltage of the assembly shall be equal to or higher than the values
251 stated for the transient overvoltage’s occurring in the electrical system(s) to which the circuit is
252 designed to be connected.
253 DBO’s shall comply with a minimum overvoltage category III (see IEC 60364-4-44) according
254 to Table G.1 of Annex G of IEC 61439-1:2020.
255 5.3.1 Rated current of an assembly (InA)
256 Addition:
257 See Annex CC.1 for when a generator e.g. photovoltaic systems, wind turbines, batteries is used as
258 an additional source of supply in parallel with another source that is connected to the DBO. .
259 5.4 Rated diversity factor (RDF)
260 Addition:
261 In the absence of an agreement between the DBO manufacturer and user concerning the actual
262 load currents, the type of load, the assumed loading of the outgoing circuits of the DBO or group
263 of outgoing circuits may be based on the values in Table 101.
264 The assumed load current is the rated current of the protective device, I , as required by the user,
n
265 multiplied with the loading factor of Table 101.
266 6 Information
267 Clause 6 of IEC 61439-1:2020 is applicable except as follows.
268 6.1 Assembly designation marking
269 Addition to first paragraph:
270 The test of 10.2.7.1 only applies to DBOs intended for outdoor installation.
271 Addition of the following new items:
272 h) degree of protection if greater than IP 2XC.

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273 6.2.2 Instructions for handling, installation, operation and maintenance
274 Addition to first paragraph:
275 If required, the original or assembly manufacturer shall provide in their documentation, any
276 routine verification required to be carried out by the installer for the DBO to conform to IEC
277 61439-3.
278 6.3 Device and/or component identification
279 Addition:
280 For RCDs supplying more than one final circuit, it shall be possible for ordinary persons to identify
281 which outgoing circuits the RCD supplies e.g. by providing labels for the installer to apply to the DBO
282 after installation. The identification means shall be visible without accessing live parts.
283 7 Service conditions
284 Clause 7 of IEC 61439-1:2020 is applicable except as follows.
285 7.1.2 Pollution degree
286 Addition:
287 A minimum pollution degree 2 applies.
288 8 Constructional requirements
289 Clause 8 of IEC 61439-1:2020 is applicable except as follows.
290 8.1.3.2.2 Resistance of insulating materials to normal heat
291 Addition:
292 Note This clause applies to covers and enclosures made of insulating materials.
293 8.2.1 Protection against mechanical impact (IK code)
294 Replacement:
295 The DBO shall comply with the following IK codes according to IEC 62262
296 – IK 05 for a DBO for indoor use.
297 – IK 07 for a DBO for outdoor use.
298 Compliance shall be verified according to 10.2.6.
299 8.2.2 Protection against contact with live parts, ingress of solid foreign bodies and water
300 (IP code)
301 Replacement of the second paragraph:
302 The degree of protection of a DBO shall be at least IP 2XC after installation in accordance with
303 the DBO manufacturer’s instructions.
304 IP 2XC shall be maintained when operating devices e.g. switching and operating test buttons
305 in normal use. The degree of protection can be temporarily reduced when permitted in a product
306 standard for use by ordinary / unskilled persons e.g. IEC 60269-3 for replacing a fuse-link, the
307 degree of protection may temporarily be reduced to IP1X.
308 Deletion of 5th and 6th paragraphs and the associated EXAMPLES
309 8.4.2.3 Barriers or enclosures
310 Replacement of first paragraph:
311 Air-insulated live parts shall be inside enclosures or behind barriers. The enclosures or barriers
312 shall provide a degree of protection of at least IPXXC.

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313 8.5.3 Selection of switching devices and components
314 Addition:
315 When a switch-disconnector, circuit-breaker without overcurrent protection or an isolating
316 switch is incorporated in the DBO, it shall conform to IEC 60947-3, IEC 60947-2 or IEC 60669-
317 2-4 as appropriate to the DBO ratings.
318 Outgoing circuits shall contain protective devices, intended to be operated by ordinary persons,
319 e.g. conforming to IEC 60898-1, IEC 61008, IEC 61009, IEC 62423, IEC 62606 and
320 IEC 60269-3.
321 An incoming protective device incorporated within the DBO not conforming to a product
322 standard intended to be operated by ordinary persons, shall require a key or tool for re-closing
323 after tripping and for the replacement of a fuse. Alternatively, a label shall be located in the
324 vicinity of the incoming protective device stating that re-closing of the tripped device and the
325 replacement of a fuse shall only be carried out by an instructed or skilled person.
326 Circuit-breakers shall be designed or installed in a way that it shall not be possible to modify
327 their settings or calibration without a deliberate act involving the use of a key or tool.
328 8.6.1 Main circuits
329 Replacement of second paragraph:
330 Each of the conductors between the incoming unit and outgoing unit as well as the components
331 included in these units may be rated on the basis of the reduced short-circuit stresses occurring
332 on the load side of the respective outgoing short-circuit protective device, provided that these
333 conductors are arranged so that under normal operation an internal short-circuit between
334 phases and/or between phases and earth is not to be expected (see 8.6.4 of IEC 61439-1:2020).
335 8.8 Terminals for external cables
336 Addition:
337 When a device or component in an out-going circuit does not incorporate a neutral terminal, the
338 number of neutral terminals of a DBO shall be not less than one outgoing terminal for each
339 outgoing circuit r
...