IEC 60352-7:2020

IEC 60352-7 ®
Edition 2.0 2020-12
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Solderless connections –
Part 7: Spring clamp connections – General requirements, test methods and

practical guidance
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.220.10 ISBN 978-2-8322-9214-3

– 2 – IEC 60352-7:2020 RLV © IEC:2020
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope and object . 8
2 Normative references . 8
3 Terms and definitions . 9
4 Requirements . 12
4.1 Workmanship . 12
4.2 Tools . 12
5 Pre-requisites for basic test schedule . 12
5.1 Spring clamp terminations . 12
5.1.1 Materials . 12
5.1.2 Surface finishes . 13
5.1.3 Design features . 13
5.1.4 Dimensions . 13
5.2 Wires . 13
5.2.1 General . 13
5.2.2 Materials . 13
5.2.3 Dimensions . 13
5.2.4 Surface finishes . 13
5.2.5 Wire insulation . 13
5.3 Spring clamp connections . 14
6 Tests Testing . 14
6.1 General . 14
Test methods and test requirements .
6.2 Standard conditions for testing . 14
6.3 Preconditioning . 14
6.4 Recovery . 14
6.5 Mounting of specimen . 14
7 Tests . 15
7.1 General examination . 15
7.2 Mechanical tests . 15
7.2.1 Tensile strength . 15
7.2.2 Wire deflection. 16
7.2.3 Vibration . 19
7.2.4 Repeated connections and disconnections . 20
7.3 Electrical tests . 21
7.3.1 Contact resistance . 21
7.3.2 Electrical load and temperature . 22
7.4 Climatic tests . 23
7.4.1 General . 23
7.4.2 Rapid change of temperature . 23
7.4.3 Climatic sequence . 23
7.4.4 Flowing mixed gas corrosion test . 23
8 Test schedules . 23
8.1 General . 23

8.2 Basic test schedule . 24
8.2.1 General . 24
8.2.2 Initial examination . 24
8.2.3 Testing of spring clamp connections with spring clamp terminations with
and without a specified wire range . 24
8.3 Full test schedule . 25
8.3.1 General . 25
8.3.2 Initial examination . 25
8.3.3 Testing of spring clamp connections with and without a specified wire
range . 25
8.4 Flow charts . 27
Annex A (informative) Practical guidance . 32
A.1 Current-carrying capacity . 32
A.2 Tool information . 32
A.3 Termination information . 32
A.3.1 General . 32
A.3.2 Design features . 32
A.3.3 Materials . 33
A.3.4 Surface finishes . 33
A.4 Wire information. 33
A.4.1 General . 33
A.4.2 Materials . 34
A.4.3 Surface finishes . 34
A.4.4 Stripping information . 34
A.5 Connection information . 35
Bibliography . 36

Figure 1 – Examples of spring clamp connections . 11
Figure 2 – Example of a spring clamp terminal . 12
Figure 3 – Information for the wire deflection test. 19
Figure 4 – Test arrangement, vibration . 20
Figure 5 – Test arrangement, current method . 21
Figure 6 – Basic test schedule (see 8.2) . 29
Figure 7 – Full test schedule (see 8.3) . 31
Figure A.1 – Correctly stripped wire . 34
Figure A.2 – Examples of stripping faults . 35

Table 1 – Values of tensile strength . 16
Table 2 – Values of force for wire deflection test . 18
Table 3 – Vibration, test severities . 20
Table 4 – Rated current of the wires, initial and final contact resistance . 22
Table 5 – Number of specimens required . 24
Table 6 – Test group P1 . 25
Table 7 – Test group P2 . 25
Table 8 – Test group A . 26
Table 9 – Test group B . 26
Table 10 – Test group C . 26

– 4 – IEC 60352-7:2020 RLV © IEC:2020
Table 11 – Test group D . 27

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SOLDERLESS CONNECTIONS –
Part 7: Spring clamp connections – General requirements,
test methods and practical guidance

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.
This redline version of the official IEC Standard allows the user to identify the changes
made to the previous edition. A vertical bar appears in the margin wherever a change
has been made. Additions are in green text, deletions are in strikethrough red text.

– 6 – IEC 60352-7:2020 RLV © IEC:2020
International Standard IEC 60352-7 has been prepared by subcommittee SC 48B: Electrical
connectors, of IEC technical committee 48: Electrical connectors and mechanical structures
for electrical and electronic equipment.
This second edition cancels and replaces the first edition of IEC 60352-7, published in 2002.
This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) correction of the two flow charts in Figure 6 and Figure 7,
b) split the content into more clauses for better separation between full test schedule and
basic test schedule,
c) relocating the content of former Clause 6 Practical guidance into an informative Annex A,
as now common in the IEC 60352 series for solderless connections,
d) clarification on conductor types with reference to classes defined in IEC 60228.
The text of this International Standard is based on the following documents:
FDIS Report on voting
48B/2823/CDV 48B/2851/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
This document was drafted in accordance with ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60352 series, published under the general title Solderless
connections, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates that it
contains colours which are considered to be useful for the correct understanding of its
contents. Users should therefore print this document using a colour printer.

INTRODUCTION
This part of IEC 60352 covers spring clamp connections and includes requirements, tests and
practical guidance information.
Two test schedules are provided.
a) The basic test schedule applies to spring clamp connections which conform to all
requirements of Clause 5. These requirements are derived from experience with
successful applications of such spring clamp connections.
b) The full test schedule applies to spring clamp connections which do not fully conform to all
requirements of Clause 5, for example which are manufactured using materials or finishes
not included in Clause 5.
This approach permits cost and time effective performance verification using a limited basic
test schedule for established spring clamp connections and an expanded full test schedule for
spring clamp connections requiring more extensive performance validation.
The values given in this document are minimum values, which are harmonized with other IEC
documents. Other standards may specify other values.

– 8 – IEC 60352-7:2020 RLV © IEC:2020
SOLDERLESS CONNECTIONS –
Part 7: Spring clamp connections – General requirements,
test methods and practical guidance

1 Scope and object
This part of IEC 60352 is applicable to spring clamp connections made with stripped wire
without further preparation:
2 2
– solid conductors of 0,32 mm to 3,7 mm nominal diameter (0,08 mm to 10 mm
cross‑section), or
2 2
– stranded conductors of 0,08 mm to 10 mm cross-section, or
2 2
– flexible conductors of 0,08 mm to 10 mm cross-section,
according to IEC 60228 or IEC 60189-3 for use in telecommunication electrical and electronic
equipment and in electronic devices employing similar techniques components.
Information on materials and data from industrial experience is included in addition to the test
procedures to provide electrically stable connections under prescribed environmental conditions.
The object of this document is to determine the suitability of spring clamp connections under
specified mechanical, electrical and atmospheric conditions.
NOTE IEC Guide 109 advocates the need to minimize the impact of a product on the natural environment
throughout the product life cycle. It is understood that some of the materials permitted in this document may can
have a negative environmental impact. As technological advances lead to acceptable alternatives for these
materials, they will be eliminated from this document.
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 60050(581):1978, International Electrotechnical Vocabulary (IEV) – Chapter 581: Electro-
mechanical components for electronic equipment
Amendment 1 (1998)
IEC 60068-1:19882013, Environmental testing – Part 1: General and guidance
Amendment 1 (1992)
IEC 60189-3:19882007, Low-frequency cables and wires with PVC insulation and PVC sheath
– Part 3: Equipment wires with solid or stranded conductor wires, PVC insulated, in singles,
pairs and triples
IEC 60228:19782004, Conductors of insulated cables
Amendment 1 (1993)
IEC 60512 (all parts), Connectors for electronic equipment – Tests and measurements
IEC 60512-1-100, Connectors for electronic equipment – Tests and measurements – Part 1-100:
General – Applicable publications

IEC 60512-1, Connectors for electrical and electronic equipment – Tests and measurements –
Part 1: Generic specification
IEC 60512-1-1, Connectors for electronic equipment – Tests and measurements – Part 1-1:
General examination – Test 1a: Visual examination
IEC 60512-1-2, Connectors for electronic equipment – Tests and measurements – Part 1-2:
General examination – Test 1b: Examination of dimension and mass
IEC 60512-2-1, Connectors for electronic equipment – Tests and measurements – Part 2-1:
Electrical continuity and contact resistance tests – Test 2a: Contact resistance – Millivolt level
method
IEC 60512-2-2, Connectors for electronic equipment – Tests and measurements – Part 2-2:
Electrical continuity and contact resistance tests – Test 2b: Contact resistance – Specified
test current method
IEC 60512-2-5, Connectors for electronic equipment – Tests and measurements – Part 2-5:
Electrical continuity and contact resistance tests – Test 2e: Contact disturbance
IEC 60512-6-4, Connectors for electronic equipment – Tests and measurements – Part 6-4:
Dynamic stress tests – Test 6d: Vibration (sinusoidal)
IEC 60512-9-2, Connectors for electronic equipment – Tests and measurements – Part 9-2:
Endurance tests – Test 9b: Electrical load and temperature
IEC 60512-11-1, Connectors for electrical and electronic equipment – Tests and
measurements – Part 11-1: Climatic tests – Test 11a – Climatic sequence
IEC 60512-11-4, Connectors for electronic equipment – Tests and measurements – Part 11-4:
Climatic tests – Test 11d: Rapid change of temperature
IEC 60512-11-7, Connectors for electronic equipment – Tests and measurements – Part 11-7:
Climatic tests – Test 11g: Flowing mixed gas corrosion test
IEC 60512-16-20, Electromechanical components for electronic equipment – Basic testing
procedures and measuring methods – Part 16: Mechanical tests on contacts and terminations
– Section 20: Test 16t: Mechanical strength (wired termination of solderless connections)
IEC 60884-1:1994, Plug and socket-outlets for household and similar purposes – Part 1:
General requirements
3 Terms and definitions
For the purpose of this part of IEC 60352, the terms and definitions of IEC 60050(581) and
IEC 60512-1 and the following additional terms and definitions apply:
For the purposes of this document, the following terms and definitions 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

IEC 60352-7 ®
Edition 2.0 2020-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Solderless connections –
Part 7: Spring clamp connections – General requirements, test methods and
practical guidance
Connexions sans soudure –
Partie 7: Connexions à ressort – Règles générales, méthodes d’essai et guide
pratique
– 2 – IEC 60352-7:2020 © IEC:2020
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Requirements . 10
4.1 Workmanship . 10
4.2 Tools . 10
5 Pre-requisites for basic test schedule . 10
5.1 Spring clamp terminations . 10
5.1.1 Materials . 10
5.1.2 Surface finishes . 11
5.1.3 Design features . 11
5.1.4 Dimensions . 11
5.2 Wires . 11
5.2.1 General . 11
5.2.2 Materials . 11
5.2.3 Dimensions . 11
5.2.4 Surface finishes . 11
5.2.5 Wire insulation . 12
5.3 Spring clamp connections . 12
6 Testing . 12
6.1 General . 12
6.2 Standard conditions for testing . 12
6.3 Preconditioning . 12
6.4 Recovery . 12
6.5 Mounting of specimen . 12
7 Tests . 13
7.1 General examination . 13
7.2 Mechanical tests . 13
7.2.1 Tensile strength . 13
7.2.2 Wire deflection. 13
7.2.3 Vibration . 16
7.2.4 Repeated connections and disconnections . 17
7.3 Electrical tests . 18
7.3.1 Contact resistance . 18
7.3.2 Electrical load and temperature . 19
7.4 Climatic tests . 19
7.4.1 General . 19
7.4.2 Rapid change of temperature . 19
7.4.3 Climatic sequence . 19
7.4.4 Flowing mixed gas corrosion test . 20
8 Test schedules . 20
8.1 General . 20
8.2 Basic test schedule . 21

8.2.1 General . 21
8.2.2 Initial examination . 21
8.2.3 Testing of spring clamp connections with spring clamp terminations with
and without a specified wire range . 21
8.3 Full test schedule . 22
8.3.1 General . 22
8.3.2 Initial examination . 22
8.3.3 Testing of spring clamp connections with and without a specified wire
range . 22
8.4 Flow charts . 23
Annex A (informative)  Practical guidance . 26
A.1 Current-carrying capacity . 26
A.2 Tool information . 26
A.3 Termination information . 26
A.3.1 General . 26
A.3.2 Design features . 26
A.3.3 Materials . 27
A.3.4 Surface finishes . 27
A.4 Wire information. 27
A.4.1 General . 27
A.4.2 Materials . 28
A.4.3 Surface finishes . 28
A.4.4 Stripping information . 28
A.5 Connection information . 29
Bibliography . 30

Figure 1 – Examples of spring clamp connections . 9
Figure 2 – Example of a spring clamp terminal . 10
Figure 3 – Information for the wire deflection test. 16
Figure 4 – Test arrangement, vibration . 17
Figure 5 – Test arrangement, current method . 18
Figure 6 – Basic test schedule (see 8.2) . 24
Figure 7 – Full test schedule (see 8.3) . 25
Figure A.1 – Correctly stripped wire . 28
Figure A.2 – Examples of stripping faults . 29

Table 1 – Values of tensile strength . 13
Table 2 – Value of force for wire deflection test . 15
Table 3 – Vibration, test severities . 17
Table 4 – Rated current of the wires, initial and final contact resistance . 19
Table 5 – Number of specimens required . 21
Table 6 – Test group P1 . 21
Table 7 – Test group P2 . 22
Table 8 – Test group A . 22
Table 9 – Test group B . 23
Table 10 – Test group C . 23
Table 11 – Test group D . 23

– 4 – IEC 60352-7:2020 © IEC:2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SOLDERLESS CONNECTIONS –
Part 7: Spring clamp connections – General requirements,
test methods and practical guidance

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.
International Standard IEC 60352-7 has been prepared by subcommittee SC 48B: Electrical
connectors, of IEC technical committee 48: Electrical connectors and mechanical structures
for electrical and electronic equipment.
This second edition cancels and replaces the first edition of IEC 60352-7, published in 2002.
This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) correction of the two flow charts in Figure 6 and Figure 7,
b) split the content into more clauses for better separation between full test schedule and
basic test schedule,
c) relocating the content of former Clause 6 Practical guidance into an informative Annex A,
as now common in the IEC 60352 series for solderless connections,

d) clarification on conductor types with reference to classes defined in IEC 60228.
The text of this International Standard is based on the following documents:
FDIS Report on voting
48B/2823/CDV 48B/2851/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
This document was drafted in accordance with ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60352 series, published under the general title Solderless
connections, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – IEC 60352-7:2020 © IEC:2020
INTRODUCTION
This part of IEC 60352 covers spring clamp connections and includes requirements, tests and
practical guidance information.
Two test schedules are provided.
a) The basic test schedule applies to spring clamp connections which conform to all
requirements of Clause 5. These requirements are derived from experience with
successful applications of such spring clamp connections.
b) The full test schedule applies to spring clamp connections which do not fully conform to all
requirements of Clause 5, for example which are manufactured using materials or finishes
not included in Clause 5.
This approach permits cost and time effective performance verification using a limited basic
test schedule for established spring clamp connections and an expanded full test schedule for
spring clamp connections requiring more extensive performance validation.
The values given in this document are minimum values, which are harmonized with other IEC
documents. Other standards may specify other values.

SOLDERLESS CONNECTIONS –
Part 7: Spring clamp connections – General requirements,
test methods and practical guidance

1 Scope
This part of IEC 60352 is applicable to spring clamp connections made with stripped wire
without further preparation:
2 2
– solid conductors of 0,32 mm to 3,7 mm nominal diameter (0,08 mm to 10 mm
cross‑section), or
2 2
– stranded conductors of 0,08 mm to 10 mm cross-section, or
2 2
– flexible conductors of 0,08 mm to 10 mm cross-section,
according to IEC 60228 or IEC 60189-3 for use in electrical and electronic equipment and
components.
Information on materials and data from industrial experience is included in addition to the test
procedures to provide electrically stable connections under prescribed environmental conditions.
The object of this document is to determine the suitability of spring clamp connections under
specified mechanical, electrical and atmospheric conditions.
NOTE IEC Guide 109 advocates the need to minimize the impact of a product on the natural environment
throughout the product life cycle. It is understood that some of the materials permitted in this document can have a
negative environmental impact. As technological advances lead to acceptable alternatives for these materials, they
will be eliminated from this document.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 60068-1:2013, Environmental testing – Part 1: General and guidance
IEC 60189-3:2007, Low-frequency cables and wires with PVC insulation and PVC sheath –
Part 3: Equipment wires with solid or stranded conductor wires, PVC insulated, in singles,
pairs and triples
IEC 60228:2004, Conductors of insulated cables
IEC 60512-1, Connectors for electrical and electronic equipment – Tests and measurements –
Part 1: Generic specification
IEC 60512-1-1, Connectors for electronic equipment – Tests and measurements – Part 1-1:
General examination – Test 1a: Visual examination
IEC 60512-1-2, Connectors for electronic equipment – Tests and measurements – Part 1-2:
General examination – Test 1b: Examination of dimension and mass

– 8 – IEC 60352-7:2020 ©
...

IEC 60352-7 ®
Edition 2.0 2020-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Solderless connections –
Part 7: Spring clamp connections – General requirements, test methods and
practical guidance
Connexions sans soudure –
Partie 7: Connexions à ressort – Règles générales, méthodes d’essai et guide
pratique
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IEC 60352-7 ®
Edition 2.0 2020-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Solderless connections –
Part 7: Spring clamp connections – General requirements, test methods and

practical guidance
Connexions sans soudure –
Partie 7: Connexions à ressort – Règles générales, méthodes d’essai et guide

pratique
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.220.10 ISBN 978-2-8322-9957-9

– 2 – IEC 60352-7:2020 © IEC:2020
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Requirements . 10
4.1 Workmanship . 10
4.2 Tools . 10
5 Pre-requisites for basic test schedule . 10
5.1 Spring clamp terminations . 10
5.1.1 Materials . 10
5.1.2 Surface finishes . 11
5.1.3 Design features . 11
5.1.4 Dimensions . 11
5.2 Wires . 11
5.2.1 General . 11
5.2.2 Materials . 11
5.2.3 Dimensions . 11
5.2.4 Surface finishes . 11
5.2.5 Wire insulation . 12
5.3 Spring clamp connections . 12
6 Testing . 12
6.1 General . 12
6.2 Standard conditions for testing . 12
6.3 Preconditioning . 12
6.4 Recovery . 12
6.5 Mounting of specimen . 12
7 Tests . 13
7.1 General examination . 13
7.2 Mechanical tests . 13
7.2.1 Tensile strength . 13
7.2.2 Wire deflection. 13
7.2.3 Vibration . 16
7.2.4 Repeated connections and disconnections . 17
7.3 Electrical tests . 18
7.3.1 Contact resistance . 18
7.3.2 Electrical load and temperature . 19
7.4 Climatic tests . 19
7.4.1 General . 19
7.4.2 Rapid change of temperature . 19
7.4.3 Climatic sequence . 19
7.4.4 Flowing mixed gas corrosion test . 20
8 Test schedules . 20
8.1 General . 20
8.2 Basic test schedule . 21

8.2.1 General . 21
8.2.2 Initial examination . 21
8.2.3 Testing of spring clamp connections with spring clamp terminations with
and without a specified wire range . 21
8.3 Full test schedule . 22
8.3.1 General . 22
8.3.2 Initial examination . 22
8.3.3 Testing of spring clamp connections with and without a specified wire
range . 22
8.4 Flow charts . 23
Annex A (informative)  Practical guidance . 26
A.1 Current-carrying capacity . 26
A.2 Tool information . 26
A.3 Termination information . 26
A.3.1 General . 26
A.3.2 Design features . 26
A.3.3 Materials . 27
A.3.4 Surface finishes . 27
A.4 Wire information. 27
A.4.1 General . 27
A.4.2 Materials . 28
A.4.3 Surface finishes . 28
A.4.4 Stripping information . 28
A.5 Connection information . 29
Bibliography . 30

Figure 1 – Examples of spring clamp connections . 9
Figure 2 – Example of a spring clamp terminal . 10
Figure 3 – Information for the wire deflection test. 16
Figure 4 – Test arrangement, vibration . 17
Figure 5 – Test arrangement, current method . 18
Figure 6 – Basic test schedule (see 8.2) . 24
Figure 7 – Full test schedule (see 8.3) . 25
Figure A.1 – Correctly stripped wire . 28
Figure A.2 – Examples of stripping faults . 29

Table 1 – Values of tensile strength . 13
Table 2 – Value of force for wire deflection test . 15
Table 3 – Vibration, test severities . 17
Table 4 – Rated current of the wires, initial and final contact resistance . 19
Table 5 – Number of specimens required . 21
Table 6 – Test group P1 . 21
Table 7 – Test group P2 . 22
Table 8 – Test group A . 22
Table 9 – Test group B . 23
Table 10 – Test group C . 23
Table 11 – Test group D . 23

– 4 – IEC 60352-7:2020 © IEC:2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SOLDERLESS CONNECTIONS –
Part 7: Spring clamp connections – General requirements,
test methods and practical guidance

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.
International Standard IEC 60352-7 has been prepared by subcommittee SC 48B: Electrical
connectors, of IEC technical committee 48: Electrical connectors and mechanical structures
for electrical and electronic equipment.
This second edition cancels and replaces the first edition of IEC 60352-7, published in 2002.
This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) correction of the two flow charts in Figure 6 and Figure 7,
b) split the content into more clauses for better separation between full test schedule and
basic test schedule,
c) relocating the content of former Clause 6 Practical guidance into an informative Annex A,
as now common in the IEC 60352 series for solderless connections,

d) clarification on conductor types with reference to classes defined in IEC 60228.
The text of this International Standard is based on the following documents:
FDIS Report on voting
48B/2823/CDV 48B/2851/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
This document was drafted in accordance with ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60352 series, published under the general title Solderless
connections, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – IEC 60352-7:2020 © IEC:2020
INTRODUCTION
This part of IEC 60352 covers spring clamp connections and includes requirements, tests and
practical guidance information.
Two test schedules are provided.
a) The basic test schedule applies to spring clamp connections which conform to all
requirements of Clause 5. These requirements are derived from experience with
successful applications of such spring clamp connections.
b) The full test schedule applies to spring clamp connections which do not fully conform to all
requirements of Clause 5, for example which are manufactured using materials or finishes
not included in Clause 5.
This approach permits cost and time effective performance verification using a limited basic
test schedule for established spring clamp connections and an expanded full test schedule for
spring clamp connections requiring more extensive performance validation.
The values given in this document are minimum values, which are harmonized with other IEC
documents. Other standards may specify other values.

SOLDERLESS CONNECTIONS –
Part 7: Spring clamp connections – General requirements,
test methods and practical guidance

1 Scope
This part of IEC 60352 is applicable to spring clamp connections made with stripped wire
without further preparation:
2 2
– solid conductors of 0,32 mm to 3,7 mm nominal diameter (0,08 mm to 10 mm
cross‑section), or
2 2
– stranded conductors of 0,08 mm to 10 mm cross-section, or
2 2
– flexible conductors of 0,08 mm to 10 mm cross-section,
according to IEC 60228 or IEC 60189-3 for use in electrical and electronic equipment and
components.
Information on materials and data from industrial experience is included in addition to the test
procedures to provide electrically stable connections under prescribed environmental conditions.
The object of this document is to determine the suitability of spring clamp connections under
specified mechanical, electrical and atmospheric conditions.
NOTE IEC Guide 109 advocates the need to minimize the impact of a product on the natural environment
throughout the product life cycle. It is understood that some of the materials permitted in this document can have a
negative environmental impact. As technological advances lead to acceptable alternatives for these materials, they
will be eliminated from this document.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 60068-1:2013, Environmental testing – Part 1: General and guidance
IEC 60189-3:2007, Low-frequency cables and wires with PVC insulation and PVC sheath –
Part 3: Equipment wires with solid or stranded conductor wires, PVC insulated, in singles,
pairs and triples
IEC 60228:2004, Conductors of insulated cables
IEC 60512-1, Connectors for electrical and electronic equipment – Tests and measurements –
Part 1: Generic specification
IEC 60512-1-1, Connectors for electronic equipment – Tests and measurements – Part 1-1:
General examination – Test 1a: Visual examination
IEC 60512-1-2, Connectors for electronic equipment – Tests and measurements – Part 1-2:
General examination – Test 1b: Examination of dimension and mass

– 8 – IEC 60352-7:2020 © IEC:2020
IEC 60512-2-1, Connectors for electronic equipment – Tests and measurements – Part 2-1:
Electrical continuity and contact resistance tests – Test 2a: Contact resistance – Millivolt level
method
IEC 60512-2-2, Connectors for electronic equipment – Tests and measurements – Part 2-2:
Electrical continuity and contact resistance tests – Test 2b: Contact resistance – Specified
test current method
IEC 60512-2-5, Connectors for electronic equipment – Tests and measurements – Part 2-5:
Electrical continuity and contact resistance tests – Test 2e: Contact disturbance
IEC 60512-6-4, Connectors for electronic equipment – Tests and measurements – Part 6-4:
Dynamic stress tests – Test 6d: Vibration (sinusoidal)
IEC 60512-9-2, Connectors for electronic equipment – Tests and measurements – Part 9-2:
Endurance tests – Test 9b: Electrical load and temperature
IEC 60512-11-1, Connectors for electrical and electronic equipment – Tests and
measurements – Part 11-1: Climatic tests – Test 11a – Climatic sequence
IEC 60512-11-4, Connectors for electronic equipment – Tests and measurements – Part 11-4:
Climatic tests – Test 11d: Rapid change of temperature
IEC 60512-11-7, Connectors for electronic equipment – Tests and measurements – Part 11-7:
Climatic tests – Test 11g: Flowing mixed gas corrosion test
IEC 60512-16-20, Electromechanical components for electronic equipment – Basic testing
procedures and measuring methods – Part 16: Mechanical tests on contacts and terminations
– Section 20: Test 16t: Mechanical strength (wired termination of solderless connections)
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
3.1
spring clamp termination
part of the contact or terminal to which one single conductor only is connected by means of a
spring
3.1.1
universal spring clamp termination
spring clamp termination intended to accept solid, stranded and flexible unprepared
conductors
Note 1 to entry: For the meaning of solid, stranded and flexible, see IEC 60228 where conductors are classified
as class 1 (solid conductors), class 2 (stranded conductors), class 5 (flexible conductors) and class 6 (flexible
conductors which are more flexible than class 5).

3.1.2
non-universal spring clamp termination
spring clamp termination intended to accept conductors of one class only, for example solid
conductors only, or conductors of two classes only, for example solid and stranded but not
flexible
Note 1 to entry: For the meaning of solid, stranded and flexible, see IEC 60228 where conductors are classified
as class 1 (solid conductors), class 2 (stranded conductors), class 5 (flexible conductors) and class 6 (flexible
conductors which are more flexible than class 5).
3.1.3
push-in spring clamp termination
non-universal spring clamp termination in which the connection is made by pushing in a solid
or stranded conductor without the aid of a tool or of an actuating element
Note 1 to entry: For the meaning of solid and stranded, see IEC 60228 where solid conductors are classified as
class 1, stranded conductors are classified as class 2.
3.2
spring clamp connection
solderless connection achieved by clamping a conductor with a spring clamp termination
SEE: Figure 1
Figure 1a – Spring clamp connection, operated without a tool

Figure 1b – Spring clamp connection, operated with a tool

Figure 1c – Spring clamp connection, operated with an actuating element

Figure 1d – Spring clamp connections, with a push-in spring clamp termination, with solid wires
Figure 1 – Examples of spring clamp connections

– 10 – IEC 60352-7:2020 © IEC:2020
3.3
spring clamp terminal
terminal designed to accept a conductor for the purpose of establishing a spring clamp
connection
SEE: Figure 2
Figure 2 – Example of a spring clamp terminal
3.4
spring clamp connecting device
device for the electrical connection of one or more conductors comprising one or more spring
clamp terminations and, if necessary, insulation and/or auxiliary parts
3.5
actuating element
part of a spring clamp termination or terminal to which an external force is to be applied, and
the resulting movement of which provides a means for activating or deactivating the spring
4 Requirements
4.1 Workmanship
The connection shall be processed in a careful and workmanlike manner, in accordance with
good current practice. Annex A (informative) provides practical guidance and may constitute a
benchmark for the assessment of workmanship.
NOTE Some industry sectors (e.g. automotive, aerospace, marine, nuclear, military) use workmanship standards
which can be considered upon agreement between manufacturer and user.
4.2 Tools
Tools, if necessary, shall be used and inspected according to the instructions given by the
manufacturer.
5 Pre-requisites for basic test schedule
5.1 Spring clamp terminations
5.1.1 Materials
– Materials for the current-carrying parts:
suitable grades of copper or copper alloy shall be used.

– Materials for the spring clamp parts:
suitable (according to manufacturer's instructions) grades of copper alloy or steel shall
be used.
5.1.2 Surface finishes
The contact area of the current-carrying parts shall be plated with tin or tin-alloy.
The surface shall be free of detrimental contamination or corrosion.
5.1.3 Design features
Spring clamp terminations shall be designed so that the spring clamp parts establish a force
to connect the conductors which ensures that the necessary contact pressure is maintained.
In a spring clamp connecting device, each conductor shall be clamped individually.
The openings for use of a tool intended to assist the insertion or withdrawal of the conductor
shall be clearly distinguishable from the conductor's entry hole.
5.1.4 Dimensions
The suitability of a spring clamp connection depends on the dimensions of the termination
together with the characteristics of the materials used.
The dimensions of the termination shall be chosen so as to be suitable for (i.e. able to accept)
the cross-sectional area of the conductor or the range of conductors for which the termination
is designed.
The suitability is verified by applying the test schedules given in Clause 8.
5.2 Wires
5.2.1 General
Wires with solid, stranded and flexible conductors according to IEC 60228 or IEC 60189-3
shall be used depending on the type of spring clamp terminations.
5.2.2 Materials
The conductor used shall be made of annealed copper.
5.2.3 Dimensions
Wires with the following dimensions shall be used:
2 2
to 10 mm
– solid wires of 0,32 mm to 3,7 mm nominal diameter (0,08 mm
cross-section), or
2 2
– stranded wires of 0,08 mm to 10 mm cross-section, or
2 2
– flexible wires of 0,08 mm to 10 mm cross-section.
5.2.4 Surface finishes
The conductor shall be unplated or plated with tin or tin-alloy.
The conductor surface shall be free of contamination and corrosion which degrades
performance.
– 12 – IEC 60352-7:2020 © IEC:2020
5.2.5 Wire insulation
The insulation shall be capable of being readily stripped from the conductor without changing
the physical characteristics of the conductor or strands.
5.3 Spring clamp connections
a) The combination of conductor and spring clamp termination shall be compatible.
b) The wire shall be stripped to the correct length specified by the manufacturer. The
stripped part of the wire shall not be damaged and shall be clean and free from particles
of insulation.
c) The conductor shall be correctly located in the spring clamp termination at the correct
depth specified by the manufacturer.
All strands of the wire shall be within the spring clamp termination.
6 Testing
6.1 General
As explained in the introduction, there are two test schedules which shall be applied
according to the following condition:
a) spring clamp connections which conform to all the requirements of Clause 5 shall be
tested in accordance with and meet the requirements of the basic test schedule, see 8.2;
b) spring clamp connections which do not fully conform to all the requirements of Clause 5,
for example, those which are made with different wire types and/or termination sizes
and/or materials, shall be tested and meet the requirements of the full test schedule given
in 8.3.
6.2 Standard conditions for testing
Unless otherwise specified, all tests shall be carried out under standard conditions for testing
as specified in IEC 60512-1.
The ambient temperature and the relative humidity at which the measurements are made shall
be stated in the test report.
In case of dispute about test results, the test shall be repeated at one of the test conditions
for referee measurements and tests set out in IEC 60068-1.
6.3 Preconditioning
Where specified, the connections shall be preconditioned under standard conditions for
testing for a period of 24 h, in accordance with IEC 60512-1.
6.4 Recovery
Where specified, the specimen shall be allowed to recover under standard conditions for
testing for a period of 1 h to 2 h, after conditioning.
6.5 Mounting of specimen
a) When mounting is required in a test, the specimens shall be mounted using the normal
mounting method, unless otherwise specified.
b) Each test specimen shall consist of one spring clamp connection prepared as required in
the test schedules.
When more test specimens are required, they may be part of the same multipole spring
clamp connecting devices.
7 Tests
7.1 General examination
The examination shall be carried out in accordance with Test 1a of IEC 60512-1-1, and
Test 1b of IEC 60512-1-2. The visual examination test may be carried out with magnification
up to approximately five times.
All spring clamp terminations and wires shall be examined to ensure that the applicable
requirements of Clause 5 have been met.
7.2 Mechanical tests
7.2.1 Tensile strength
The test shall be carried out in accordance with Test 16t, method A, of IEC 60512-16-20.
Requirement:
The tensile strength of spring clamp connections shall be not less than specified in Table 1,
unless otherwise specified by the detail specification.
Table 1 – Values of tensile strength
Conductor cross- Values of tensile
section strength
mm N minimum
0,08 up to 0,22 4
(not included)
0,22 10
0,34 15
0,5 20
0,75 30
1,0 35
1,5 40
2,5 50
4,0 60
6,0 80
10,0 90
7.2.2 Wire deflection
NOTE This test method is similar to the deflection test method for screwless terminals described in IEC 60884-1.
Spring clamp terminations shall be so designed that the inserted solid conductor remains
clamped, even when the conductor has been deflected during normal installation, for
example, during mounting in a box, and the deflecting stress is transferred to the spring clamp
termination.
Compliance is checked by the following test which is made on specimens which have not
been used for any other test.
a) Test apparatus
The test apparatus, the principle of which is shown in Figure 3, shall be so constructed
that:
– 14 – IEC 60352-7:2020 © IEC:2020
– a specified conductor, properly inserted into a terminal, is allowed to be deflected in
any of the 12 directions differing from each other by 30°, with a tolerance referred to
each direction of ±5° and;
– the starting point can be varied by 10° and 20° from the original point.
A reference direction need not be specified.
The deflection of the conductor from its straight position to the testing positions shall be
effected by means of a suitable device applying a specified force to the conductor at
a certain distance from the terminal.
The deflecting device shall be so designed that:
– the force is applied in the direction perpendicular to the undeflected conductor;
– the deflection is attained without rotation or displacement of the conductor within the
clamping unit, and
– the force remains applied whilst the prescribed voltage drop measurement is made.
Provisions shall be made so that the voltage drop across the spring clamp termination
under test can be measured when the conductor is connected, as shown for example in
Figure 3.
b) Test method
The specimen is mounted on the fixed part of the test apparatus in such a way that the
specified conductor inserted into the spring clamp termination under test can be freely
deflected.
The surface of the test conductor shall be free of detrimental contamination or corrosion.
NOTE If necessary, the inserted conductor can be permanently bent around obstacles, so that these do not
influence the results of the test.
In some cases, with the exception of the case of guidance for the conductors, it may be
advisable to remove those parts of the specimen which do not allow the deflection of the
conductor corresponding to the force to be applied.
A spring clamp termination is fitted as for normal use with a solid copper conductor having
the smallest cross-sectional area as specified by the manufacturer and is submitted to a
first test sequence; unless the first test sequence has failed, the same spring clamp
termination is submitted to a second test sequence using the conductor having the largest
cross-sectional area.
The force for deflecting the conductor is specified in Table 2, the distance of 100 mm
being measured from the extremity of the terminal, including the guidance for the
conductor, if any, to the point of application of the force to the conductor.
The test is made with continuous current (i.e. the current is not switched on and off during
the test); a suitable power supply should be used so that the current variations are kept
within ±5 % during the test.
Table 2 – Value of force for wire deflection test
Cross-section of the test conductor Force for deflecting the test
conductors
mm N
0,5 up to 0,75 0,09
(not included)
0,75 0,16
1,0 0,25
1,5 0,5
2,5 1,0
4 2,0
6 3,5
10 7,0
The forces are chosen so that they stress the conductors close to the limit of
elasticity.
c) Test procedure
A tenth of the test current assigned to the wire according to Table 4 is passed through the
spring clamp connection under test. A force, according to Table 2, is applied to the test
conductor inserted in the spring clamp termination under test in the direction of one of the
12 directions shown in Figure 3 and the voltage drop across this spring clamp connection
is measured. The force is then removed.
The force is then applied successively in each of the remaining 11 directions shown in
Figure 3 following the same test procedure.
If at any of the 12 test directions the voltage drop is greater than 2,5 mV, the force is kept
applied in this direction until the voltage drop is reduced to a value below 2,5 mV, but for
not more than 1 min. After the voltage drop has reached a value lower than or equal to
2,5 mV, the force is kept applied in the same direction for a further period of 30 s during
which period the voltage drop shall not have increased.
The other specimens of the set are tested following the same test procedure, but moving
the 12 directions of the force so that they differ by approximately 10° for each specimen.
If one specimen of the set has failed at one of the directions of application of the test
force, the tests are repeated on another set of specimens, all of which shall comply with
the repeated tests.
– 16 – IEC 60352-7:2020 © IEC:2020

Figure 3 – Information for the wire deflection test
7.2.3 Vibration
The test shall be carried out in accordance with Test 6d of IEC 60512-6-4.
The component shall be firmly held on a vibration table.
An example of a suitable test arrangement for testing a component containing a spring clamp
connection is shown in Figure 4. Contact disturbance shall be monitored during the vibration
test in accordance with Test 2e of IEC 60512-2-5, see Table 3.
The limit of duration of contact disturbance shall be 1 µs unless otherwise specified by the
detail specification.
Figure 4 – Test arrangement, vibration
Table 3 – Vibration, test severities
Range of frequency, Hz 10 to 55 10 to 500 10 to 2 000
Overall duration, h 2,25 6 7,5
Displacement amplitude below the cross-over frequency, mm 0,35 0,35 1,5
Acceleration amplitude above the cross-over frequency, m/s
− 50 200
Directions 3 axes 3 axes 3 axes
Number of sweep cycles per direction 10 10 10

Unless otherwise specified, the test shall be carried out in the 10 Hz to 55 Hz range.
7.2.4 Repeated connections and disconnections
The object of this test is to assess the ability of a spring clamp termination with a wire range
specified by the manufacturer to withstand a specified number of connections
and disconnections.
If the termination is designed to accept a range of conductor sizes:
• for the smallest conductor
– all cycles but the last one shall be carried out with the largest conductor size specified.
The last cycle and the final measurement shall be carried out with the smallest
conductor size specified.
• for the largest conductor
– all cycles shall be carried out with the largest conductor size specified. The final
measurement shall be carried out with the largest conductor size specified.
A stripped wire of the largest size specified shall be inserted into the spring clamp termination
under test in the specified manner. After this, the conductor shall be extracted in the specified
manner. This shall be considered as one test cycle.
The last of the specified number of test cycles consists of only inserting the unprepared
stripped wire into the termination, so as to have a spring clamp connection at the end of the
specified number of test cycles.
The same spring clamp termination shall be submitte
...