IEC 62873-3-3:2016

IEC 62873-3-3 ®
Edition 1.0 2016-09
INTERNATIONAL
STANDARD
Residual current operated circuit-breakers for household and similar use –
Part 3-3: Specific requirements for RCDs with screw-type terminals for external
untreated aluminium conductors and with aluminium screw-type terminals for
use with copper or with aluminium conductors
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IEC 62873-3-3 ®
Edition 1.0 2016-09
INTERNATIONAL
STANDARD
Residual current operated circuit-breakers for household and similar use –

Part 3-3: Specific requirements for RCDs with screw-type terminals for external

untreated aluminium conductors and with aluminium screw-type terminals for

use with copper or with aluminium conductors

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.120.50 ISBN 978-2-8322-3615-4

– 2 – IEC 62873-3-3:2016 © IEC 2016
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references. 6
3 Terms and definitions . 6
4 Classification . 7
5 Characteristics of RCDs . 7
6 Marking and other product information . 7
7 Standard conditions for operation in service and for installation . 8
8 Requirements for construction and operation . 8
9 Tests . 9
9.1 General . 9
9.2 Test conditions . 10
9.3 Current cycling test . 10
9.3.1 General . 10
9.3.2 Preparation . 11
9.3.3 Test arrangement . 11
9.3.4 Temperature measurement . 12
9.3.5 Test method and acceptance criteria . 12
Bibliography . 17

Figure 1 – General arrangement for the test . 14
Figure 2 – Test specimen example 1 . 15
Figure 3 – Test specimen example 2 . 16
Figure 4 – Test specimen example 3 . 16
Figure 5 – Test specimen example 4 . 16
Figure 6 – Test specimen example 5 . 16

Table 1 – Marking for terminals . 8
Table 2 – Connectable cross-sections of aluminium conductors for screw-type
terminals . 8
Table 3 – List of tests according to the material of conductors and terminals . 9
Table 4 – Connectable conductors and their theoretical diameters . 10
Table 5 – Cross-sections (S) of aluminium test conductors corresponding to the rated
currents . 10
Table 6 – Test conductor length . 11
Table 7 – Equalizer and busbar dimensions . 12
Table 8 – Test current as a function of rated current . 13
Table 9 – Example of calculation for determining the average temperature deviation D . 14

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
RESIDUAL CURRENT OPERATED CIRCUIT-BREAKERS
FOR HOUSEHOLD AND SIMILAR USE –

Part 3-3: Specific requirements for RCDs with screw-type terminals for
external untreated aluminium conductors and with aluminium screw-type
terminals for use with copper or with aluminium conductors

FOREWORD
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International Standard IEC 62873-3-3 has been prepared by subcommittee 23E: Circuit
breakers and similar equipment for household use, of IEC technical committee 23: Electrical
accessories.
The text of this standard is based on the following documents:
FDIS Report on voting
23E/966/FDIS 23E/984/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 publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 4 – IEC 62873-3-3:2016 © IEC 2016
A list of all parts of the IEC 62873 series published under the general title Residual current
operated circuit-breakers for household and similar use can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC website under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

INTRODUCTION
This document is part of the series described in the outline document IEC 62873-1.

– 6 – IEC 62873-3-3:2016 © IEC 2016
RESIDUAL CURRENT OPERATED CIRCUIT-BREAKERS
FOR HOUSEHOLD AND SIMILAR USE –

Part 3-3: Specific requirements for RCDs with screw-type terminals for
external untreated aluminium conductors and with aluminium screw-type
terminals for use with copper or with aluminium conductors

1 Scope
This part of IEC 62873 applies to RCDs equipped with screw-type terminals of copper – or of
alloys containing at least 58 % of copper (if worked cold) or at least 50 % of copper (if worked
otherwise), or of other metal or suitably coated metal, no less resistant to corrosion than
copper and having mechanical properties no less suitable – for use with untreated aluminium
conductors, or with screw-type terminals of aluminium material for use with copper or
aluminium conductors.
This part of IEC 62873 cannot be used alone but it is intended to be applied together with an
RCD product standard (IEC 61008-1 or IEC 61009-1) if an RCD is equipped with screw-type
terminals for external untreated aluminium conductors and with aluminium screw-type
terminals for use with copper or with aluminium conductors.
In this part of IEC 62873, copper-clad and nickel-clad aluminium conductors are considered
as aluminium conductors.
NOTE In AT, AU and DE, the use of aluminium screw-type terminals for use with copper conductors is not
allowed.
– In AT and DE, terminals for aluminium conductors only are not allowed;
– In ES, the use of aluminium conductors is not allowed for final circuits in household and similar installations
e.g. offices, shops;
– In DK, the minimum cross-sectional area for aluminium conductors is 16 mm .
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 61008-1, Residual current operated circuit-breakers without integral overcurrent
protection for household and similar uses (RCCBs) – Part 1: General rules
IEC 61009-1, Residual current operated circuit-breakers with integral overcurrent protection
for household and similar uses (RCBOs) – Part 1: General rules
IEC 62873-2, Residual current operated circuit-breakers for household and similar use –
Part 2: Residual current devices (RCDs) – Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62873-2 and the
following apply.
3.1
treated conductor
contact area of a conductor that has had its oxide layer on the outside strands scraped away
and/or has had a compound added to improve connectability and/or prevent corrosion
3.2
untreated conductor
unprepared conductor
conductor which has been cut and the insulation of which has been removed for insertion into
a terminal
Note 1 to entry: A conductor, the shape of which is arranged for introduction into a terminal or the strands of
which are twisted to consolidate the end, is considered to be an unprepared conductor.
[SOURCE: IEC 60050-442:1998, 442-01-26]
3.3
equalizer
arrangement used in the test loop to ensure an equipotentiality point and uniform current
density in a stranded conductor, without adversely affecting the temperature of the
conductor(s)
3.4
reference conductor
continuous length of the same type and size conductor as that used in the terminal unit under
test and connected in the same series circuit, which enables the reference temperature and,
if required, reference resistance to be determined
3.5
stability factor
Sf
measure of temperature stability of a terminal unit during the current cycling test
4 Classification
Clause 4 of the RCD product standard applies.
5 Characteristics of RCDs
Clause 5 of the RCD product standard applies.
6 Marking and other product information
In addition to Clause 6 of the RCD product standard, the following requirements apply.
The terminal marking defined in Table 1 shall be marked on the RCD, near the terminals.
The other information concerning the number of conductors, the screw torque values (if
different from Table 11 of the RCD product standard) and the cross-sections
...