IEC TS 60947-7-5:2021

Low-voltage switchgear and controlgear - Part 7-5: Ancillary equipment - Terminal blocks for aluminium conductors

IEC TS 60947-7-5:2021 specifies requirements for terminal blocks with screw-type or screwless-type clamping units primarily intended for industrial or similar use and to be fixed to a support to provide electrical and mechanical connection. This document can be used for terminal blocks for connection between aluminium conductors or aluminium to copper conductors. It applies to terminal blocks intended to connect round conductors, with or without special preparation, having a cross-section between 2,5 mm2 and 300 mm2 (AWG 12 to 600 kcmil), intended to be used in circuits of a rated voltage not exceeding 1 000 V AC (up to 1 000 Hz) or 1 500 V DC.

Appareillage à basse tension - Partie 7-5: Matériels accessoires - Blocs de jonction pour conducteurs en aluminium

L'IEC TS 60947-7-5:2021 spécifie les exigences relatives aux blocs de jonction avec organes de serrage du type à vis ou du type sans vis essentiellement destinés à un usage industriel ou analogue, et à être fixés sur un support afin d'assurer la connexion électrique et mécanique. Le présent document peut être utilisé pour les blocs de jonction qui assurent le raccordement entre des conducteurs en aluminium ou entre des conducteurs en aluminium et en cuivre. Il s'applique aux blocs de jonction destinés à raccorder les conducteurs ronds, avec ou sans préparation particulière, dont la section est comprise entre 2,5 mm2 et 300 mm2 (AWG 12 à 600 kcmil) et destinés à être utilisés dans des circuits présentant une tension assignée maximale de 1 000 V en courant alternatif (jusqu'à 1 000 Hz) ou de 1 500 V en courant continu.

General Information

• Status: Published
• Publication Date: 21-Nov-2021
• ICS: 29.130.20 - Low voltage switchgear and controlgear
• Technical Committee: SC 121A - Low-voltage switchgear and controlgear
• Drafting Committee: PT 60947-7-5 - TC 121/SC 121A/PT 60947-7-5
• Current Stage: PPUB - Publication issued
• Start Date: 22-Nov-2021
• Completion Date: 25-Nov-2021

Standards Content (Sample)

IEC TS 60947-7-5 ®
Edition 1.0 2021-11
TECHNICAL
SPECIFICATION
SPECIFICATION
TECHNIQUE
colour
inside
Low-voltage switchgear and controlgear –
Part 7-5: Ancillary equipment – Terminal blocks for aluminium conductors

Appareillage à basse tension –
Partie 7-5: Matériels accessoires – Blocs de jonction pour conducteurs en
aluminium
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IEC TS 60947-7-5 ®
Edition 1.0 2021-11
TECHNICAL
SPECIFICATION
SPECIFICATION
TECHNIQUE
colour
inside
Low-voltage switchgear and controlgear –

Part 7-5: Ancillary equipment – Terminal blocks for aluminium conductors

Appareillage à basse tension –

Partie 7-5: Matériels accessoires – Blocs de jonction pour conducteurs en

aluminium
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.130.20 ISBN 978-2-8322-1041-9

– 2 – IEC TS 60947-7-5:2021 © IEC 2021
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 8
3 Terms and definitions . 8
4 Classification . 9
5 Characteristics . 10
5.1 Summary of characteristics . 10
5.2 Type of terminal block . 10
5.3 Rated and limiting values . 10
5.3.1 Rated voltage . 10
5.3.2 Short-time withstand current . 10
5.3.3 Standard cross-sections . 10
5.3.4 Nominal cross-section . 11
5.3.5 Nominal connecting capacity . 11
5.3.6 Nominal current . 11
6 Product information . 12
6.1 Marking . 12
6.2 Additional information . 12
7 Normal service, mounting and transport conditions . 13
8 Constructional and performance requirements . 13
8.1 Constructional requirements . 13
8.1.1 Clamping units . 13
8.1.2 Mounting . 13
8.1.3 Clearances and creepage distances . 13
8.1.4 Terminal identification and marking . 14
8.1.5 Resistance to abnormal heat and fire . 14
8.1.6 Nominal cross-section and nominal connection capacity . 14
8.2 Performance requirements . 15
8.2.1 General . 15
8.2.2 Temperature-rise . 16
8.2.3 Dielectric properties . 16
8.2.4 Short-time withstand current . 17
8.2.5 Voltage drop . 17
8.2.6 Electrical performance after ageing (for screwless-type terminal blocks
only) . 17
8.2.7 Current-cycle ageing test . 17
8.3 Electromagnetic compatibility . 17
9 Tests . 17
9.1 Kinds of test . 17
9.2 General . 17
9.3 Verification of mechanical characteristics . 18
9.3.1 General . 18
9.3.2 Attachment of the terminal block on its support . 18
9.3.3 Mechanical properties of clamping units . 20
9.4 Verification of electrical characteristics . 21

9.4.1 General . 21
9.4.2 Verification of clearances and creepage distances . 21
9.4.3 Dielectric tests . 22
9.4.4 Verification of the voltage drop . 22
9.4.5 Temperature-rise test . 23
9.4.6 Short-time withstand current test . 24
9.4.7 Ageing test (for screwless-type terminal blocks only) . 24
9.4.8 Current-cycle ageing test . 24
9.5 Verification of thermal characteristics . 28
9.6 Verification of EMC characteristics . 30
9.6.1 Immunity . 30
9.6.2 Emission . 30
9.7 Items subject to agreement between manufacturer and user . 30
Bibliography . 31

Figure 1 – Arrangement for test according to 9.3.2 . 19
Figure 2 – Arrangement for test according to 9.4.5 and for the verification of voltage drop . 23
Figure 3 – Three-step test for AC/ DC . 25
Figure 4 – Arrangement for current-cycle ageing test according to 9.4.8 . 26
Figure 5 – Schematic of conductor preparation (cross-section greater than 25 mm ) . 27
Figure 6 – Current-cycle ageing test procedure . 28
Figure 7 – Arrangement for test according to 9.5 . 29
Figure 8 – Point of test flame contact . 30

Table 1 – Standard cross-section of conductors . 11
Table 2 – Range for the nominal current for metric wire sizes . 15
Table 3 – Range for the nominal current for AWG or kcmil wire sizes . 16
Table 4 – Attachment test parameters . 19

– 4 – IEC TS 60947-7-5:2021 © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 7-5: Ancillary equipment –
Terminal blocks for aluminium 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
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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
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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.
IEC TS 60947-7-5 has been prepared by subcommittee 121A: Low-voltage switchgear and
controlgear, of IEC technical committee 121: Switchgear and controlgear and their assemblies
for low voltage. It is a Technical Specification.
This publication shall be read in conjunction with the sixth edition of IEC 60947-1:2020 and the
third edition of IEC 60947-7-1:2009. The provisions of the general rules dealt with in
IEC 60947-1:2020 and the requirements for terminal blocks of IEC 60947-7-1:2009 are
applicable to this publication, where specifically called for. Clauses and subclauses, tables,
figures and annexes thus applicable are identified by reference to IEC 60947-1:2020 or
IEC 60947-7-1:2009.
The text of this Technical Specification is based on the following documents:
Draft Report on voting
121A/418/DTS 121A/428A/RVDTS
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Technical Specification is English.
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.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under 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 document 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.

– 6 – IEC TS 60947-7-5:2021 © IEC 2021
INTRODUCTION
The connection of aluminium conductors, as defined in IEC 60228, and suitable terminations
for such conductors has been deemed relevant such that a specific test program for aluminium-
suited terminals and the development of a new publication under the scope of IEC SC121A are
appropriate.
Additional tests were deemed necessary due to experience showing that reliable electrical
connections for aluminium conductors require more consideration than those with copper mainly
due to different oxidative behaviour and mechanical characteristics of the materials.
It is well known that when two different metals come into contact; galvanic corrosion is likely to
occur. This is an electrochemical process where electrons will flow from the less noble metal to
the more noble metal. This effect will be sped up by additional DC current flow and the presence
of an electrolyte. In an electrical contact situation this process shall be considered, as it may
result in contamination of the contact area with corrosion products and reduction of contact
pressure and contact area when the termination is affected.
This document is based on the well-known test program for copper conductors as defined in
IEC 60947-7-1. However, further tests have been modified and added to those for copper
conductors. These additional tests were derived from those already defined in IEC 61545,
IEC 60269-2, IEC 60947-7-1 and IEC 60947-1.
There is a new current-cycling ageing test which includes pre-conditioning of the specimens by
storage in a cold environment followed by dry heat with AC for AC terminal blocks or damp heat
with DC for AC and/or DC terminal blocks, inspired by tests of Annex Q of IEC 60947-1:2020.
The current-cycling ageing test comprises a total of 768 on-off cycles. For testing the reference
value I is established from Table 2 becoming the base test current with an additional safety
al
margin of 1,25. The manufacturer is required to provide the I value to the user in his
al
documentation.
Therefore, in contrast to IEC 60947-7-1, it was necessary to introduce additional marking, which
is similar that of IEC 61545.
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 7-5: Ancillary equipment –
Terminal blocks for aluminium conductors

1 Scope
This part of IEC 60947 specifies requirements for terminal blocks with screw-type or screwless-
type clamping units primarily intended for industrial or similar use and to be fixed to a support
to provide electrical and mechanical connection. This document can be used for terminal blocks
for connection between aluminium conductors or aluminium to copper conductors. It applies to
terminal blocks intended to connect round conductors, with or without special preparation,
2 2
having a cross-section between 2,5 mm and 300 mm (AWG 12 to 600 kcmil), intended to be
used in circuits of a rated voltage not exceeding 1 000 V AC (up to 1 000 Hz) or 1 500 V DC.
This document can be used as a guide to qualify terminal blocks for conductors out of aluminium
not complying with IEC 60228 (e.g. smaller than 10 mm , flexible or other materials). This
document can also be used as a guide to qualify other types of terminal blocks for conductors
out of aluminium other than feed through terminal blocks (e.g. partially insulated terminal
blocks).
NOTE 1 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 document does not apply to clamping units:
– dedicated to any other types of switchgear and controlgear;
– for connection by crimping, brazing, soldering or welding;
– for data and signalling circuits;
– for flat quick-connect terminations, insulation-piercing connecting devices and twist-on
connecting devices, for which separate parts are under consideration.
NOTE 2 In case of use of special types of conductors (e.g. cladded conductors) which require a special preparation,
this document can be used as a guide.
NOTE 3 In some countries, national regulation for installation rules can allow different cross-sections. For internal
wiring (inside enclosures), other rules or product standards can be applicable.
NOTE 4 For connections to copper conductors only, IEC 60947-7-1:2009 is applicable.
NOTE 5 In USA, UL 1059 applies and in Canada, CSA C22.2 No. 158 applies.
Where applicable in this document, the term “clamping unit” is used instead of the term
“terminal”. This is taken into account in case of reference to IEC 60947-1:2020.

– 8 – IEC TS 60947-7-5:2021 © IEC 2021
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 60068-2-1:2007, Environmental testing – Part 2-1: Tests – Test A: Cold
IEC 60068-2-2:2007, Environmental testing – Part 2-2: Tests – Test B: Dry heat
IEC 60068-2-78:2012, Environmental testing – Part 2-78: Tests – Test Cab: Damp heat, steady
state
IEC 60228, Conductors of insulated cables
IEC 60364-5-52:2009, Low-voltage electrical installations – Part 5-52: Selection and erection
of electrical equipment – Wiring systems
IEC 60695-11-5:2016, Fire hazard testing – Part 11-5: Test flames – Needle-flame test method
– Apparatus, confirmatory test arrangement and guidance
IEC 60947-1:2020, Low-voltage switchgear and controlgear – Part 1: General rules
IEC 60947-7-1:2009, Low-voltage switchgear and controlgear – Part 7-1: Ancillary equipment
– Terminal blocks for copper conductors
ISO 4046-4:2016, Paper, board, pulps and related terms − Vocabulary – Part 4: Paper and
board grades and converted products
3 Terms and definitions
Clause 2 of IEC 60947-7-1:2009 applies with the following additions.
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
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
Note 1 to entry: In the USA and Canada, treatment of the specimens and conductors to be tested is not acceptable.
[SOURCE: IEC 61545:1996, 3.13, modified – Insertion of Note 1 to entry.]
3.2
prefilled clamping unit
clamping unit of a terminal block that is prefilled by the manufacturer with an
oxide-inhibiting compound
3.3
nominal cross-section for aluminium conductors
value of cross-section for a given type of conductor, solid, rigid stranded or flexible, stated by
the manufacturer, and to which certain thermal, mechanical and electrical requirements are
referred
Note 1 to entry: Terminal blocks may have several nominal cross-sections depending on the type of conductor.
3.4
nominal connection capacity for aluminium conductors
range of cross-sections, types of conductors and, if applicable, the number of connectable
conductors, for which the terminal block is designed
3.5
corresponding copper conductors
cross-section value of the connectable types of conductors, rigid (solid and stranded) and
flexible, stated by the manufacturer, and to which certain thermal, mechanical and electrical
requirements are referred
3.6
nominal connection capacity for copper conductors
range of cross-sections and, if applicable, the number of connectable conductors, for which the
terminal block is designed
3.7
nominal current
I
al
current, as declared by the manufacturer, based
on the nominal cross-section of the aluminium conductors
4 Classification
Distinction is made between various type of terminal blocks as follows:
– method of fixing the terminal block to the support;
– number of poles;
– type of clamping units: screw-type clamping units or screwless-type clamping units;
– ability to receive different types of conductors, e.g, solid, rigid stranded or flexible
conductors;
– ability to receive different types of conductors based on their treatment; treated, untreated,
either treated or untreated;
– ability to receive either aluminium conductors or both aluminium and copper conductors;
– ability to receive prepared conductors (see 3.5.28 of IEC 60947-1:2020);
– terminal assemblies with identical or dissimilar clamping units;
– number of clamping units on each terminal assembly;
– service conditions;
– treatment of clamping units: filled (either prefilled or filled on site), unfilled;
– suitability for AC current and/or DC current.

– 10 – IEC TS 60947-7-5:2021 © IEC 2021
5 Characteristics
5.1 Summary of characteristics
The characteristics of a terminal block are as follows:
– type of terminal block (see 5.2);
– rated and limiting values (see 5.3).
5.2 Type of terminal block
The following shall be stated:
– type of clamping units (e.g. screw-type, screwless-type);
– number of clamping units;
– treatment of conductors;
– treatment of clamping unit.
5.3 Rated and limiting values
5.3.1 Rated voltage
Subclause 5.3.1.2 and 5.3.1.3 of IEC 60947-1:2020 apply.
5.3.2 Short-time withstand current
A specified RMS value of current which a terminal block shall be able to withstand during a
specified short-time under prescribed conditions of use and behaviour (see 8.2.4 and 9.4.6).
5.3.3 Standard cross-sections
The standard values of cross-sections of round aluminium conductors to be used are contained
in Table 1.
Table 1 – Standard cross-section of conductors
Comparison between AWG/kcmil
and metric size
Metric size ISO
Equivalent
Size
metric area
2 2
AWG/kcmil
mm mm
a a
0,2 24 0,205
a a
0,324
0,34 22
a a
0,5 20 0,519
a a
0,75 18 0,82
a
- -
a a
1,3
1,5 16
a
2,5 14 2,1
4 12 3,3
6 10 5,3
10 8 8,4
16 6 13,3
25 4 21,2
35 2 33,6
50 0 53,5
70 00 67,4
95 000 85
- 0000 107,2
120 250 kcmil 127
150 300 kcmil 152
185 350 kcmil 177
240 500 kcmil 253
300 600 kcmil 304
a
For copper conductors only.
5.3.4 Nominal cross-section
The nominal cross-section shall be selected from the standard cross-sections given in Table 1.
5.3.5 Nominal connecting capacity
The manufacturer shall state for each clamping unit the material, the types and the maximum
and minimum cross-sections of conductors that can be connected and, if applicable, the number
of conductors simultaneously connectable to each clamping unit, without intermixing of different
conductor materials in one clamping unit. The manufacturer shall also state any necessary
preparation of the end of the conductor.
5.3.6 Nominal current
The manufacturer shall state the nominal current for terminal blocks. This nominal current shall
be based on the size of the aluminium conductors according to Table 2 and Table 3 and applies
to the minimum corresponding copper conductor also, if any. To determine the corresponding
copper conductor, refer to IEC 60364-5-52:2009, Table B.52.4, installation method C.
Terminal blocks for use with combination of aluminium and copper conductors have a nominal
current based on the current for aluminium conductors.

– 12 – IEC TS 60947-7-5:2021 © IEC 2021
6 Product information
6.1 Marking
A terminal block shall be marked in a durable and legible manner with the following:
a) the name of the manufacturer or a trade mark by which the manufacturer can be readily
identified;
b) a type reference permitting its identification in order to obtain relevant information from the
manufacturer or his catalogue.
6.2 Additional information
The following information shall be stated by the manufacturer, if applicable, e.g. in the
manufacturer’s data sheet or his catalogue or on the packing unit, cross-medial reference is
allowed:
a) IEC TS 60947-7-5 if the manufacturer claims compliance with this document;
b) the nominal cross-section for aluminium conductors and corresponding copper conductors,
if applicable;
c) the nominal connecting capacities, including the number of conductors simultaneous
connectable;
d) the rated insulation voltage (U );
i
e) the rated impulse withstand voltage (U ), when determined;
imp
f) service conditions, if different from those of Clause 7;
g) the following information, depending of the classification, shall be used:
– for clamping units declared for solid conductors “solid” or the abbreviations “s” or “sol”;
– for clamping units declared for rigid stranded conductors “rigid stranded” or the
abbreviation “r”;
– for clamping units declared for flexible conductors “flexible” or the abbreviation “f”;
– for clamping units declared for treated conductors “treated” or the abbreviation “t”;
– for clamping units declared for aluminium conductors “aluminium” or the abbreviation
“Al”;
– for clamping units declared for copper conductors “copper” or the abbreviation “Cu”;
– for clamping units declared for aluminium and copper conductors “aluminium and
copper” or the abbreviation “Al-Cu”.
In the case of combinations, the manufacturer shall use an appropriate combination of symbols.
In case of different classifications for different clamping units within a terminal block, the
marking shall be unambiguous either on the terminal block or in the manufacturer´s
documentation, for example with numbers.
EXAMPLE 1 Marking Al s-t Cu indicates a terminal block with clamping units suitable to connect both solid
treated aluminium conductors and all types of copper conductors as well.
h) declared nominal current for terminal blocks with aluminium conductors dependent on
nominal cross-section of conductor;
EXAMPLE 2 For one terminal block with three declared cross-sections and conductor types:
– at 16 mm : I = 45 A s-t/r-t;
al
– at 10 mm : I = 35 A s-t/f-t;
al
– at 6 mm : I = 32 A s-t.
al
i) the maintenance according to manufacturer´s instruction;

j) information about the inhibiting compound, if needed;
k) suitability to connect solid, rigid stranded and/ or flexible aluminium conductors, circular or
e.g. sectoral;
l) the description of treatment of conductor and/or clamping unit by the user, including the
application of inhibiting compound(s), if necessary;
m) suitability for AC current and/or DC current.
– Terminal blocks having passed Step 2 and Step 3 of 9.4.8 with DC current shall be
marked DC and/or AC.
– Terminal blocks having passed Step 2 and Step 3 of 9.4.8 with AC current shall be
marked AC only.
7 Normal service, mounting and transport conditions
Clause 7 of IEC 60947-1:2020 applies.
8 Constructional and performance requirements
8.1 Constructional requirements
8.1.1 Clamping units
Subclause 8.1.8.1 of IEC 60947-1:2020 applies with following additions.
The clamping units shall allow the conductors to be connected by means ensuring that a reliable
mechanical linkage and electrical contact is properly maintained.
NOTE Screw-type clamping units are not suitable for the connection of flexible connectors with tin-soldered ends.
The clamping units shall be able to withstand the force that can be applied through the
connected conductors.
Compliance is checked by inspection and by the tests of 9.3.3.1, 9.3.3.2 and 9.3.3.3.
No contact pressure shall be transmitted through insulating materials other than ceramic, or
other material with characteristics not less suitable, unless there is sufficient resiliency in the
metallic parts to compensate for any possible shrinkage of the insulating material.
The corresponding test is under consideration.
8.1.2 Mounting
Terminal blocks shall be provided with means that allow them to be securely attached to a rail
or a mounting surface.
Tests shall be made in accordance with 9.3.2.
NOTE Information on mounting on rails can be found in IEC 60715.
8.1.3 Clearances and creepage distances
For terminal blocks for which the manufacturer has stated values of rated impulse withstand
voltage (U ) and rated insulation voltage (U ), minimum values of clearances and creepage
imp i
distances are given in Table 13 of IEC 60947-1:2020 and Table 15 of IEC 60947-1:2020.

– 14 – IEC TS 60947-7-5:2021 © IEC 2021
For terminal blocks for which the manufacturer has not declared a value of rated impulse
withstand voltage (U ), guidance for minimum values is given in Annex H of
imp
IEC 60947-1:2020.
Electrical requirements are given in 8.2.3.
8.1.4 Terminal identification and marking
Subclause 8.1.8.4 of IEC 60947-1:2020 applies with the following additions.
A terminal block shall have provision, or at least space, for identification marks or numbers for
each clamping unit or terminal assembly related to the circuit of which it forms a part.
For the identification of the terminal blocks the colour combination green-yellow is not allowed.
NOTE Such provision can consist of separate marking items, such as marking tags, identification labels, etc.
8.1.5 Resistance to abnormal heat and fire
The insulation material of the terminal block shall not be adversely affected by abnormal heat
and fire.
NOTE For small parts, as specified in IEC 60695-2-11, the relevant product standard can specify another test (for
example needle flame test, according to IEC 60695-11-5). The same procedure can be applicable for other practical
reasons when the metal part is large compared to the insulating material (such as terminal blocks). The needle flame
test is used as an alternative test for addressing flame retardancy requirements for shipboard applications.
Compliance is checked by the needle flame test according to IEC 60695-11-5:2016 as specified
in 9.5 of this document.
8.1.6 Nominal cross-section and nominal connection capacity
Terminal blocks shall be so designed that:
– conductors of the nominal cross-section for aluminium conductors and the nominal
connection capacity for aluminium conductors can be accepted;
– the nominal connection capacity for copper conductors can be accepted, if applicable.
Compliance is checked by the test described in 9.3.3.4.
The verification of the corresponding copper conductors may be performed by the special test
according to 9.3.3.5.
8.2 Performance requirements
8.2.1 General
The nominal current is declared by the manufacturer, but shall be taken within the range given
nd nd
in Table 2, 2 column or Table 3, 2 column.
Table 2 – Range for the nominal current for metric wire sizes
Nominal Range for the nominal On-off time for current-
a
cross-section for cycling ageing
current
aluminium conductors
mm A min
I ≤ 14
1,5
al
14 < I ≤ 18,5
2,5
al
18,5 < I ≤ 25
al
25 < I ≤ 32
al
b
32 < I ≤ 44
60-60
al
≤ 59
44 < I
al
59 < I ≤ 73
al
73 < I ≤ 90
al
50 90 < I ≤ 110
al
70 110 < I ≤ 140
al
95 140 < I ≤ 170
al
120 170 < I ≤ 197
al
b
150 197 < I ≤ 227
90-90
al
185 227 < I ≤ 259
al
240 259 < I ≤ 305
al
300 305 < I ≤ 351
al
NOTE The principle for a range depending on cross-sectional area is taken from
Table 10 of IEC 60898-1:2015 and Table 9 of IEC 60947-1:2020.
a
The maximal value of the range is given in IEC 60364-5-52:2009, Table B.52.4 for
installation method C; except for the value for 1,5 mm , which is numerically derived
from the other values. The value for 1,5 mm is out of the scope and given for
information only.
b th
Off-times can be reduced after the 97 cycle under special conditions as described in
9.4.8.
– 16 – IEC TS 60947-7-5:2021 © IEC 2021
Table 3 – Range for the nominal current for AWG or kcmil wire sizes
Nominal Range for the nominal On-off time for
a
cross-section for current-cycling
current
aluminium conductors ageing
AWG/kcmil A min
c
I ≤ 15,5
al
15,5 < I ≤ 21
al
21 < I ≤ 28
10 al
28 < I ≤ 37 b
8 al 60-60
37 < I ≤ 49
al
49 < I ≤ 62
al
≤ 87
62 < I
2 al
87 < I ≤ 93
1 al
0 93 < I ≤ 118
al
00 118 < I ≤ 135
al
000 135 < I ≤ 152
al
0000 152 < I ≤ 176
al
b
250 kcmil 176 < I ≤ 209
90-90
al
300 kcmil 209 < I ≤ 230
al
350 kcmil 230 < I ≤ 248
al
500 kcmil 248 < I ≤ 322
al
600 kcmil 322 < I ≤ 356
al
a
Values are calculated from cross-section metric to AWG.
b th
Off-times can be reduced after the 97 cycle under special conditions as
described in 9.4.8.
c
Value for AWG 14 is out of the scope and given for information only.

8.2.2 Temperature-rise
Terminal blocks shall be tested in accordance with 9.4.5 with the test nominal current. The
temperature-rise of the terminal block shall not exceed 45 K.
8.2.3 Dielectric properties
If the manufacturer has declared a value of the rated impulse withstand voltage (U )
imp
(see 5.3.1.3 of IEC 60947-1:2020), the requirements of 8.2.3 and 8.2.3.1 of IEC 60947-1:2020
apply. If applicable, the impulse withstand voltage test shall be carried out in accordance with
9.4.3 a)).
For the verification of solid insulation, the requirements of 8.2.3, 8.2.3.2, and 8.2.3.5 of
IEC 60947-1:2020 apply. The power-frequency withstand voltage test shall be carried out in
accordance with 9.4.3 b)).
The verification of sufficient clearances and creepage distances shall be made in accordance
with 9.4.2.
For terminal blocks for which the manufacturer has not declared a value of rated impulse
withstand voltage (U ), guidance for minimum values is given in Annex H of
imp
IEC 60947-1:2020.
8.2.4 Short-time withstand current
A terminal block shall be capable of withstanding for 1 s the short-time withstand current which
corresponds to 77 A/mm of its nominal cross-section of the aluminium conductor, in
accordance with 9.4.6.
NOTE The value of 77 A/mm is derived from the relationship between the susceptance (conductance) of copper
and aluminium used for electrical conductors as given in IEC 60228.
8.2.5 Voltage drop
The voltage drop on a terminal block caused by the conductor connection, measured according
to 9.4.4, shall not exceed the values specified in 9.4.4.
8.2.6 Electrical performance after ageing (for screwless-type terminal blocks only)
Covered by 9.4.7.
8.2.7 Current-cycle ageing test
A terminal block shall be capable of withstanding environmental conditions and ageing, in
accordance with 9.4.8 with the test current equal to 1,25 multiplied with nominal current.
8.3 Electromagnetic compatibility
Subclause 8.3 of IEC 60947-1:2020 applies.
9 Tests
9.1 Kinds of test
Subclause 9.1.1 of IEC 60947-1:2020 applies with the following additions.
No routine tests are specified. The verification of the nominal cross-section according to 9.3.3.5
is a special test. All other tests are type tests.
The manufacturer shall specify the most unfavourable combination of nominal current, cross-
section and type of conductor for the temperature-rise and current-cycle ageing test. Both tests
shall be performed with this combination.
9.2 General
Unless otherwise specified, terminal blocks tested are new and in clean condition, and installed
as for normal use (see 7.3 of IEC 60947-1:2020) at an ambient temperature of 20 ± 5 °C.
NOTE 1 ”Normal use” means that five terminal blocks are m
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