IEC 60947-7-4:2013

IEC 60947-7-4


®


Edition 1.0 2013-08



INTERNATIONAL



STANDARD



NORME
INTERNATIONALE
colour
inside


Low-voltage switchgear and controlgear –
Part 7-4: Ancillary equipment – PCB terminal blocks for copper conductors

Appareillage à basse tension –
Partie 7-4: Matériels accessoires – Blocs de jonction pour cartes de circuits
imprimés pour conducteurs en cuivre


IEC 60947-7-4:2013

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IEC 60947-7-4



®



Edition 1.0 2013-08







INTERNATIONAL





STANDARD







NORME



INTERNATIONALE
colour

inside










Low-voltage switchgear and controlgear –

Part 7-4: Ancillary equipment – PCB terminal blocks for copper conductors




Appareillage à basse tension –

Partie 7-4: Matériels accessoires – Blocs de jonction pour cartes de circuits

imprimés pour conducteurs en cuivre
















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE

PRICE CODE
INTERNATIONALE

CODE PRIX U


ICS 29.130.20 ISBN 978-2-8322-1029-1



Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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– 2 – 60947-7-4 © IEC:2013


CONTENTS


FOREWORD . 4

INTRODUCTION . 6


1 General . 7

1.1 Scope . 7

1.2 Normative references . 7

2 Terms and definitions . 9

3 Classification . 10

4 Characteristics . 10
4.1 Summary of characteristics . 10
4.2 Type of PCB terminal block . 10
4.3 Rated and limiting values . 10
4.3.1 Rated voltages . 10
4.3.2 Rated current . 10
4.3.3 Standard cross-sections . 10
4.3.4 Maximum cross-section . 11
4.3.5 Connecting capacity . 11
5 Product information . 12
5.1 Marking . 12
5.2 Additional information . 13
6 Normal service, mounting and transport conditions . 13
7 Constructional and performance requirements . 13
7.1 Constructional requirements . 13
7.1.1 Clamping units . 13
7.1.2 Mounting and installation . 14
7.1.3 Clearances and creepage distances . 14
7.1.4 Terminal identification and marking . 14
7.1.5 Resistance to abnormal heat and fire . 15
7.1.6 Maximum cross-section and connecting capacity . 15
7.2 Performance requirements . 15
7.2.1 Temperature rise . 15
7.2.2 Dielectric properties . 15
7.2.3 Short-time withstand current . 15

7.2.4 Contact resistance . 16
7.2.5 Ageing test (climatic sequence and corrosion test) . 16
7.3 Electromagnetic compatibility (EMC) . 16
8 Tests . 16
8.1 Kinds of test . 16
8.2 General . 16
8.3 Verification of mechanical characteristics . 17
8.3.1 General . 17
8.3.2 Attachment of the PCB terminal block on its support . 17
8.3.3 Vacant . 17
8.3.4 Verification of the maximum cross-section and connecting capacity . 17
8.3.5 Verification of maximum cross-section (special test with gauges) . 17
8.4 Verification of electrical characteristics . 17
8.4.1 General . 17

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60947-7-4 © IEC:2013 – 3 –


8.4.2 Verification of clearances and creepage distances. 18

8.4.3 Dielectric tests . 18

8.4.4 Verification of contact resistance . 19

8.4.5 Temperature rise test . 20

8.4.6 Short-time withstand current test . 22

8.4.7 Ageing test (climatic sequence and corrosion test) . 23

8.5 Verification of thermal characteristics . 24

8.6 Verification of EMC characteristics . 25

8.6.1 General . 25

8.6.2 Immunity. 25

8.6.3 Emission. 25
Annex A (informative) Structure of a PCB terminal block . 26
Annex B (informative) Additional Information to be specified between manufacturer
and user . 27
Annex C (informative) Examples of PCBs and PCB terminal blocks for high current
application . 28
Bibliography . 30

Figure 1 – Test assembly for the measurement of contact resistance and temperature
rise . 20
Figure 2 – Example of wiring structure of a multi-tier PCB terminal block . 21
Figure 3 – Test assembly for the measurement of short-time withstand current . 23
Figure 4 – Test sequence . 24
Figure A.1 – Structure of a PCB terminal block . 26
Figure C.1 – Structure of a high current PCB . 28
Figure C.2 – PCB terminal block with soldered connection to the PCB . 28
Figure C.3 – PCB terminal block with screwed connection to the PCB . 29

Table 1 – Standard cross-sections of copper conductors . 11
Table 2 – Relationship between maximum cross-section and connecting capacity of
PCB terminal blocks. 12
Table 3 – Standards for clamping units and connecting methods . 14
Table 4 – Impulse withstand test voltages . 19

Table 5 – Dielectric test voltages corresponding to the rated insulation voltage . 19
Table 6 – Length of connectable conductors and conductor loops . 21
Table 7 – Examples of cross-sectional distribution of interconnections on printed
circuit boards . 22

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– 4 – 60947-7-4 © IEC:2013


INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________



LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –



Part 7-4: Ancillary equipment –

PCB terminal blocks for copper conductors



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
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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 60947-7-4 has been prepared by subcommittee 17B: Low-voltage

switchgear and controlgear, of IEC technical committee 17: Switchgear and controlgear.
The text of this standard is based on the following documents:
FDIS Report on voting
17B/1822/FDIS 17B/1827/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.
A list of all parts in the IEC 60947 series, published under the general title Low-voltage
switchgear and controlgear, can be found on the IEC website.

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60947-7-4 © IEC:2013 – 5 –


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.





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.

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– 6 – 60947-7-4 © IEC:2013


INTRODUCTION


This standard IEC 60947-7-4 for PCB terminal blocks covers not only the terminal block

requirements according to IEC 60947-7 series but also takes into account the specifications of

connectors according to IEC 61984 as the requirements for both components are highly

similar due to equivalent applications.

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60947-7-4 © IEC:2013 – 7 –


LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –



Part 7-4: Ancillary equipment –

PCB terminal blocks for copper conductors








1 General


1.1 Scope
This part of IEC 60947 specifies requirements for PCB terminal blocks primarily intended for
industrial or similar use.
Mounting and fixing on the printed circuit board is made by soldering, press-in or equivalent
methods to provide electrical and mechanical connection between copper conductors and the
printed circuit board.
This standard applies to PCB terminal blocks intended to connect copper conductors, with or
2 2
without special preparation, having a cross-section between 0,05 mm and 300 mm (AWG
30/600 kcmil), intended to be used in circuits of a rated voltage not exceeding 1 000 V a.c. up
to 1 000 Hz or 1 500 V d.c.
NOTE 1 Large cross section terminal blocks are dedicated to specific design of high current PCBs. The range up
to 300 mm² is kept to cover any possible application. Examples of high current PCBs and PCB terminal blocks are
shown in Annex C.
NOTE 2 AWG is the abbreviation of “American Wire Gage” (Gage (US) = Gauge (UK));
kcmil = 1 000 cmil;
1 cmil = 1 circular mil = surface of a circle having a diameter of 1 mil;
1 mil = 1/1 000 inch.
This standard may be used as a guide for special types of PCB terminal blocks with
components, such as disconnect units, integrated cartridge fuse-links and the like.
If applicable, in this standard the term “clamping unit” is used instead of “terminal”. This is
taken into account in case of references to IEC 60947-1.
1.2 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 60068-2-20, Environmental testing – Part 2-20: Tests – Test T: Test methods for
solderability and resistance to soldering heat of devices with leads
IEC 60352-1, Solderless connections – Part 1: Wrapped connections – General requirements,
test methods and practical guidance
IEC 60352-2, Solderless connections – Part 2: Crimped connections – General requirements,
test methods and practical guidance
IEC 60352-3, Solderless connections – Part 3: Solderless accessible insulation displacement
connections – General requirements, test methods and practical guidance

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IEC 60352-4, Solderless connections – Part 4: Solderless non-accessible insulation

displacement connections – General requirements, test methods and practical guidance


IEC 60352-5, Solderless connections – Part 5: Press-in connections – General requirements,

test methods and practical guidance


IEC 60352-6, Solderless connections – Part 6: Insulation piercing connections – General

requirements, test methods and practical guidance


IEC 60352-7, Solderless connections – Part 7: Spring clamp connections – General

requirements, test methods and practical guidance

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 60512-4-1, Connectors for electronic equipment – Tests and measurements – Part 4-1:
Voltage stress tests – Test 4a: Voltage proof
IEC 60512-5-2, Connectors for electronic equipment – Tests and measurements – Part 5-2:
Current-carrying capacity tests – Test 5b: Current-temperature derating
IEC 60512-11-7, Connectors for electronic equipment – Tests and measurements – Part 11-7:
Climatic tests – Test 11g: Flowing mixed gas corrosion test
IEC 60512-11-9, Connectors for electronic equipment – Tests and measurements – Part 11-9:
Climatic tests – Test 11i: Dry heat
IEC 60512-11-10, Connectors for electronic equipment – Tests and measurements – Part 11-
10: Climatic tests – Test 11j: Cold
IEC 60695-2-11, Fire hazard testing – Part 2-11: Glowing/hot-wire based test methods –
Glow-wire flammability test method for end-products
IEC 60695-2-12, Fire hazard testing - Part 2-12: Glowing/hot-wire based test methods - Glow-
wire flammability index (GWFI) test method for materials
IEC 60695-2-13, Fire hazard testing – Part 2-13: Glowing/hot-wire based test methods –
Glow-wire ignition temperature (GWIT) test method for materials

IEC 60947-1:2007, Low-voltage switchgear and controlgear – Part 1: General rules
Amendment 1: 2010
IEC 60998-2-3, Connecting devices for low-voltage circuits for household and similar
purposes – Part 2-3: Particular requirements for connecting devices as separate entities with
insulation-piercing clamping units
IEC 60999-1, Connecting devices – Electrical copper conductors – Safety requirements for
screw-type and screwless-type clamping units – Part 1: General requirements and particular
2 2
requirements for clamping units for conductors from 0,2 mm up to 35 mm (included)
IEC 60999-2, Connecting devices – Electrical copper conductors – Safety requirements for
screw-type and screwless-type clamping units – Part 2: Particular requirements for clamping
2 2
units for conductors above 35 mm up to 300 mm (included)

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60947-7-4 © IEC:2013 – 9 –


IEC 61210, Connecting devices – Flat quick-connect terminations for electrical copper

conductors – Safety requirements


ISO 6988, Metallic and other non-organic coatings – Sulfur dioxide test with general

condensation of moisture



2 Terms and definitions


For the purposes of this document, the terms and definitions given in IEC 60947-1, as well as

the following, apply.

2.1
printed circuit board
PCB
piece of insulating material with fixed metal traces to connect electronic components
Note 1 to entry: Printed circuit boards are typically subdivided according to:
– their structure (e.g. single- and double-sided, multilayers);
– the nature of the base material (e.g. rigid, flexible).
2.2
PCB terminal block
part intended to be mounted on a printed circuit board and carrying one or more mutually
insulated contact units and which provides an electrical and mechanical connection between
copper conductor and printed circuit board
2.3
rated current
current value assigned by the manufacturer which the PCB terminal block can carry
continuously (without interruption) and simultaneously through all its poles connected with the
maximum cross-section, preferably at an ambient temperature of 40 °C, without the upper
limiting temperature being exceeded
2.4
contact unit
conductive part establishing the connection between printed circuit board and connectable
conductor(s)
Note 1 to entry: See Annex A.
2.5

upper limiting temperature
ULT
maximum temperature in the PCB terminal block as outcome (sum) of the ambient
temperature and the temperature rise due to current flow, at which the PCB terminal block is
intended to be still operable
Note 1 to entry: At ambient temperature = ULT the available temperature rise due to current flow is zero, thus the
current carrying capacity of the PCB terminal block is zero.
2.6
lower limiting temperature
LLT
minimum temperature of a PCB terminal block assigned by the manufacturer, at which a PCB
terminal block is intended to operate

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3 Classification


A distinction is made between various types of PCB terminal blocks, if applicable, as follows:


a) type of clamping unit (see 7.1.1);

b) ability to accept prepared conductors (see 2.3.28 of IEC 60947-1:2007,

Amendment 1 (2010));


c) type of electrical contact to the printed circuit board;

d) type of mechanical fastening to the printed circuit board;

e) number of poles;

f) pitch (center to center pin spacing);
g) contact unit with identical or dissimilar clamping units;
h) number of clamping units on each contact unit;
i) service conditions.
4 Characteristics
4.1 Summary of characteristics
The characteristics of a PCB terminal block are as follows:
– type of PCB terminal block (see 4.2);
– rated and limiting values (see 4.3).
4.2 Type of PCB terminal block
The following shall be stated:
– type of clamping units (see 7.1.1);
– type of contacting on the printed circuit board;
– number of clamping units.
4.3 Rated and limiting values
4.3.1 Rated voltages
Subclauses 4.3.1.2 and 4.3.1.3 of IEC 60947-1:2007 apply.
4.3.2 Rated current

Verification of the rated current specified by the manufacturer is made according to 8.4.5.
If an ambient temperature other than 40 °C is used for the definition of the rated current, the
manufacturer should state, in the technical documentation, the ambient temperature on which
the rating is based, with reference, if appropriate, to the derating curve defined in
IEC 60512-5-2, Test 5b.
The derating curv
...