IEC 61238-1-3:2018

IEC 61238-1-3 ®
Edition 1.0 2018-05
INTERNATIONAL
STANDARD
Compression and mechanical connectors for power cables –
Part 1-3: Test methods and requirements for compression and mechanical
connectors for power cables for rated voltages above 1 kV (U = 1,2 kV) up to
m
30 kV (U = 36 kV) tested on non-insulated conductors
m
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IEC 61238-1-3 ®
Edition 1.0 2018-05
INTERNATIONAL
STANDARD
Compression and mechanical connectors for power cables –

Part 1-3: Test methods and requirements for compression and mechanical

connectors for power cables for rated voltages above 1 kV (U = 1,2 kV) up to

m
30 kV (U = 36 kV) tested on non-insulated conductors
m
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.060.20 ISBN 978-2-8322-5647-3

– 2 – IEC 61238-1-3:2018 © IEC 2018
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 8
4 Symbols . 10
5 General . 11
5.1 Definition of classes . 11
5.2 Conductor . 11
5.3 Connectors and installation procedure . 12
5.4 Range of approval. 12
6 Electrical tests . 13
6.1 Installation . 13
6.1.1 General . 13
6.1.2 Through connectors and terminations . 14
6.1.3 Branch connectors . 14
6.2 Measurements . 14
6.2.1 General . 14
6.2.2 Electrical resistance measurements . 14
6.2.3 Temperature measurements . 15
6.3 Heat cycling test . 15
6.3.1 General . 15
6.3.2 First heat cycle . 15
6.3.3 Second heat cycle . 16
6.3.4 Subsequent heat cycles . 17
6.4 Short-circuit test . 18
6.4.1 General . 18
6.4.2 Aluminium conductors with cross-sectional areas below 1 000 mm and
copper conductors with cross-sectional areas below 630 mm . 18
6.4.3 Aluminium conductors with cross-sectional areas ≥ 1 000 mm and
copper conductors with cross-sectional areas ≥ 630 mm . 19
6.5 Assessment of results . 19
6.6 Requirements . 19
6.7 Examples of electrical test loop configurations and associated parameters . 20
7 Mechanical test . 26
7.1 General . 26
7.2 Method . 26
7.3 Requirements . 27
8 Test report . 27
8.1 General . 27
8.2 Electrical tests . 27
8.3 Mechanical test . 27
Annex A (normative) Equalizers and their preparation . 28
A.1 Requirements for equalizers . 28
A.2 Recommendations for welding equalizers . 28
Annex B (normative) Measurements . 30

B.1 Potential measuring positions for typical connectors . 30
B.2 Temperature measurement . 30
B.3 Equivalent conductor resistance . 30
Annex C (informative) Recommendations to decrease uncertainties of measurement . 31
C.1 Handling the test loop . 31
C.2 Measurements, instruments and readings . 31
Annex D (normative) Calculation of adiabatic short-circuit current . 32
Annex E (informative) Determination of the value of the short-circuit current . 33
Annex F (normative) Calculation method . 34
F.1 General . 34
F.2 Measurements made . 34
F.3 Connector resistance factor k . 34
F.4 Initial scatter δ . 35
F.5 Mean scatter β . 35
F.6 Change in resistance factor of each connector . 37
F.6.1 General . 37
F.6.2 Line of best fit . 37
F.6.3 Confidence interval δ . 37
i
F.6.4 Change in resistance factor D . 38
F.7 Resistance factor ratio λ. 38
F.8 Maximum temperatures θ . 38
max
Annex G (informative) Explanation on assessment of results of electrical tests on
connectors . 39
G.1 History . 39
G.2 Short examination of the assessment methods of IEC 61238-1 compared

with the Italian standard CEI 20-28 and the British standard BS 4579-3 . 39
G.3 The IEC 61238-1 method of assessing test results . 40
Annex H (informative) Electrical tests on cable terminal lugs for application in
separable connectors . 42
H.1 Principle . 42
H.2 Lengths . 42
H.3 Temperature measurement . 42
H.4 Median connector . 43
H.5 Electrical test parameters . 43
Bibliography . 44

Figure 1 – Example of second heat cycle profile . 17
Figure 2 – Typical electrical test loops for through connectors and terminal lugs . 22
Figure 3 – Typical electrical test loop for branch connectors . 23
Figure 4 – Typical cases of resistance measurements . 26
Figure A.1 – Preparation of equalizers . 29
Figure E.1 – Determination of equivalent RMS value of current during the short-circuit test . 33
Figure F.1 – Graphic example of assessment of a Class A individual connector . 36
Figure H.1 – Test arrangement . 43

Table 1 – Minimum period of temperature stability . 16
Table 2 – Electrical resistance measurements during the electrical test . 18

– 4 – IEC 61238-1-3:2018 © IEC 2018
Table 3 – Electrical test requirements . 20
Table 4 – Selection of tensile force withstand values for the mechanical test . 27
Table D.1 – Material properties . 32
Table G.1 – Summary of assessed behaviour of a tested connector . 40

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
COMPRESSION AND MECHANICAL
CONNECTORS FOR POWER CABLES –
Part 1-3: Test methods and requirements for compression and mechanical
connectors for power cables for rated voltages above 1 kV (U = 1,2 kV)
m
up to 30 kV (U = 36 kV) tested on non-insulated conductors
m
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
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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6) All users should ensure that they have the latest edition of this publication.
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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.
International Standard IEC 61238-1-3 has been prepared by IEC technical committee 20:
Electric cables.
This first edition, together with IEC 61238-1-1 and IEC 61238-1-2, cancels and replaces
IEC 61238-1:2003.
This edition includes the following significant technical changes with respect to
IEC 61238-1:2003:
a) The scope has been widened to cover connectors for conductors from 10 mm down to
2 2
2,5 mm and has been limited to 1 200 mm for connectors for copper and aluminium
conductors because test experience and applications are rare for conductors of larger
cross-sectional areas.
– 6 – IEC 61238-1-3:2018 © IEC 2018
b) A new mechanical class has been introduced to satisfy the demand for connectors
subjected to higher mechanical forces than those specified in Class 1 for conductors of
larger cross-sectional areas.
c) For the electrical test, a maximum elevated heating current has been set in order to avoid
unrealistic current densities during the test which may change the properties of tested
connectors.
d) For the short-circuit test, the method of calculation and requirements have been updated.
e) For the mechanical test, the methods and requirements have been updated.
f) A proposal for an electrical test on cable terminal lugs for application in separable
connectors has been introduced.
The text of this standard is based on the following documents:
FDIS Report on voting
20/1790/FDIS 20/1805/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 61238 series, published under the general title Compression and
mechanical connectors for power cables, 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.
A bilingual version of this publication may be issued at a later date.

INTRODUCTION
The IEC 61238 series has been divided into the following parts:
Part 1-1: Test methods and requirements for compression and mechanical connectors for
power cables for rated voltages up to 1 kV (U = 1,2 kV) tested on non-insulated
m
conductors
Part 1-2: Test methods and requirements for insulation piercing connectors for power
cables for rated voltages up to 1 kV (U = 1,2 kV) tested on insulated conductors
m
Part 1-3: Test methods and requirements for compression and mechanical connectors for
power cables for rated voltages above 1 kV (U = 1,2 kV) up to 30 kV
m
(U = 36 kV) tested on non-insulated conductors
m
This Part 1-3 of IEC 61238 deals with type tests for compression and mechanical connectors
for use on copper or aluminium conductors of power cables for rated voltages above 1 kV
(U = 1,2 kV) up to 30 kV (U = 36 kV).
m m
When a design of connector meets the requirements of this document, then it is expected that
in service:
a) the resistance of the connection will remain stable within specified limits;
b) the temperature of the connector will be of the same order or less than that of the
conductor during current heating;
c) if the intended use demands it, application of short-circuit currents will not affect a)
and b);
d) independently from the electrical performance, conforming axial tensile strength will
ensure an acceptable mechanical performance for the connections to the cable
conductors.
It should be stressed that, although the object of the electrical and mechanical tests specified
in this document is to prove the suitability of connectors for most operating conditions, they do
not necessarily apply to situations where a connector may be raised to a high temperature by
virtue of connection to a highly rated plant, to corrosive conditions, or where the connector is
subjected to external mechanical stresses such as excessive vibration, shock and large
displacement after installation. In these instances, the tests in this document may need to be
supplemented by special tests agreed between supplier and purchaser.
This document does not invalidate existing approvals of products achieved on the basis of
national standards and specifications and/or the demonstration of satisfactory service
performance. However, products approved according to such national standards or
specifications cannot directly claim approval to this document.
Once successfully completed, these tests are not repeated unless changes are made in
material, manufacturing process and design which might adversely change the connector
performance characteristics.
– 8 – IEC 61238-1-3:2018 © IEC 2018
COMPRESSION AND MECHANICAL
CONNECTORS FOR POWER CABLES –
Part 1-3: Test methods and requirements for compression and mechanical
connectors for power cables for rated voltages above 1 kV (U = 1,2 kV)
m
up to 30 kV (U = 36 kV) tested on non-insulated conductors
m
1 Scope
This part of IEC 61238 applies to compression and mechanical connectors for power cables
for rated voltages above 1 kV (U = 1,2 kV) up to 30 kV (U = 36 kV), for example buried
m m
cables or cables installed in buildings, having
a) conductors complying with IEC 60228 having nominal cross-sectional areas between
2 2 2 2
2,5 mm and 1 200 mm for copper and between 16 mm and 1 200 mm for aluminium,
excluding Milliken conductors;
b) a maximum continuous conductor temperature not exceeding 90 °C.
This document is not applicable to connectors for overhead line conductors nor to connectors
with a sliding contact.
The object of this document is to define the type test methods and requirements which apply
to compression and mechanical connectors for power cables with copper or aluminium
conductors. The reference method is to perform the tests on unused conductors.
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 60050-461, International Electrotechnical Vocabulary – Part 461: Electric cables
(available at http://www.electropedia.org)
IEC 60228, Conductors of insulated cables
IEC 60493-1, Guide for the statistical analysis of ageing test data – Part 1: Methods based on
mean values of normally distributed test results
IEC 60949:1988, Calculation of thermally permissible short-circuit currents, taking into
account non-adiabatic heating effects
IEC 60949:1988/AMD1:2008
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-461 and the
following 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
connector
device for connecting a conductor to an equipment terminal or for connecting two
or more conductors to each other
[SOURCE: IEC 60050-461:2008, 461-17-03, modified – the definition has been revised.]
3.2
through connector
device for connecting two consecutive lengths of conductor together
[SOURCE: IEC 60050-461:2008, 461-17-04, modified – the term "joint ferrule" has been
deleted and the definition revised.]
3.3
branch connector
device for connecting a branch conductor to a main conductor at an intermediate point on the
latter
[SOURCE: IEC 60050-461:2008, 461-17-05, modified – the term "branch ferrule" has been
deleted and in the definition "metallic" has been deleted.]
3.4
termination
device fitted to the end of a cable conductor to ensure electrical connection with other parts of
the system
[SOURCE: IEC 60050-461:2008, 461-10-01, modified – "conductor" has been added and "and
to maintain insulation up to the point of connection" has been deleted.]
3.5
terminal lug
device to connect a cable conductor to other electrical equipment
[SOURCE: IEC 60050-461:2008, 461-17-01, modified – "metallic" has been deleted.]
3.6
palm
part of a terminal lug used to make the connection to electrical equipment
[SOURCE: IEC 60050-461:2008, 461-17-07]
3.7
barrel
part of a device into which the conductor to be connected is
introduced
[SOURCE: IEC 60050-461:2008, 461-17-06]
3.8
reference conductor
length of unjointed bare conductor or conductor with the insulation removed, which is included
in the test loop and which enables the reference temperature and reference resistance to be
determined
– 10 – IEC 61238-1-3:2018 © IEC 2018
3.9
equalizer
arrangement used in the test loop to ensure a point of equipotential and uniform current
distribution in a stranded conductor
3.10
compression jointing
method of securing a connector to a conductor by using a special tool to produce permanent
deformation of the connector and the conductor
3.11
mechanical jointing
method of securing a connector to a conductor, for example by means of a bolt or screw
acting on the latter or by alternative methods
3.12
median connector
connector which during the first heat cycle records the third highest temperature of the six
connectors in the test loop
3.13
conductor
part of a cable which has the specific function of carrying current
[SOURCE: IEC 60050-461:2008, 461-01-01]
3.14
family of connectors
group of connectors of a manufacturer to be considered of the same design criteria, the same
material characteristic and the same installation procedure
4 Symbols
A nominal cross-sectional area of the conductor
D change in the resistance factor of the connector
I direct current flowing through a connection during resistance measurement
I equivalent RMS short-circuit current
RMS
I alternating current necessary to maintain the reference conductor at its
N
equilibrium temperature
I direct current flowing through the reference conductor/conductors during
r
resistance measurement
k
connector resistance factor: ratio of the resistance of a connector to that of the
resistance of the equivalent length of the reference conductor
k initial connector resistance factor: ratio of the resistance of a connector to that of
the resistance of the equivalent length of the reference conductor at cycle no. 0
l , l , l lengths of each connector assembly associated with the measurement positions
a b j
in the test set-up after installation
l
length of the reference conductor between measurement positions
r
R measured resistance value of connector/conductor installation under an electrical
test corrected to 20 °C
R measured resistance value of the reference conductor corrected to 20 °C
r
R length related calculated resistance value of a connector under an electrical test
j
corrected to 20 °C
t heating time
t time necessary for the connectors and the reference conductor to cool to a value
equal to or less than 35 °C
U potential difference between measurement positions while current I is applied
U potential difference between measurement positions on a reference conductor
r
while current I is applied
r
temperature coefficient of resistance at 20 °C
α
mean scatter of the connector resistance factors
β
initial scatter of the connector resistance factors
δ
λ resistance factor ratio: the actual resistance factor of the connector at each
measurement stage divided by its initial resistance factor
θ temperature of a connector
maximum temperature recorded on a connector over the total period of test
θ
max
during heat cycling
temperature of the reference conductor determined in the first heat cycle
θ
R
temperature of the related reference conductor at the moment of measuring
θ
ref
θ
max
5 General
5.1 Definition of classes
Although it is not possible to define precisely the service conditions for all applications, the
following requirements have been identified.
a) Electrical requirements:
Class A
Connectors related to this document are intended for electricity distribution or industrial
networks in which they can be subjected to short-circuits of relatively high intensity and
duration.
b) Mechanical requirements:
Class 1
Connectors subjected to a mechanical pull-out force related to the conductor nominal
cross-sectional area and material (according to Table 4) but limited to 20 kN pull-out force.
These are, for example, connectors for underground cable joints.
Class 2
Connectors subjected to a mechanical pull-out force above 20 kN and related to the
conductor nominal cross-sectional area and material (according to Table 4). This class is
only applicable to conductor nominal cross-sectional areas ≥ 400 mm copper and
≥ 630 mm aluminium. These are, for example, connectors in cable installations where
thermomechanical forces are estimated to exceed 20 kN.
Hence, the three classes correspond to the following tests:
Class A: heat cycling and short-circuit tests;
Class 1: mechanical test with limited maximum tensile force;
Class 2: mechanical test with no maximum tensile force.
5.2 Conductor
The following information shall be recorded in the test report:

– 12 – IEC 61238-1-3:2018 © IEC 2018
– conductor material;
– nominal cross-sectional area, dimensions and shape;
– detail of conductor construction shall be given when known, or can be determined by
inspection, for example:
• class according to IEC 60228 (solid, stranded and flexible);
• compacted or non-compacted for stranded conductor;
• number and arrangement of strands;
• type of plating, if applicable;
• type of impregnation, water blocking, etc., if applicable.
5.3 Connectors and installation procedure
The following information shall be recorded in the test report:
– the assembly method or the installation instruction that is to be used;
– tooling, dies and any necessary setting;
– if not part of the delivered product, for example at cable conductor termination: bolts, nuts,
washers, lubricant, torque, etc.;
– preparation of contact surfaces, if applicable, for example cleaning, brushing and/or
greasing of inner and/or outer conductor and/or connector surfaces;
– identification of the connector, for example name of the supplier, drawing, reference
number, type.
5.4 Range of approval
In general, tests made on one type of connector/conductor combination apply to that
arrangement only. However, to limit the number of tests, using the same conductor material,
the following is permitted:
– a connector which can be used on stranded round conductors or on stranded sector-
shaped conductors which have been rounded, is approved for both types if satisfactory
results are obtained on a compacted round conductor;
– a connector which covers a range of consecutive cross-sectional areas shall be approved,
if satisfactory results are obtained on the smallest and the largest cross-sectional area;
– if a connector is a through connector for two conductors of different cross-sectional areas,
shapes, or materials, and if the jointing method and the connector barrels used have
already been tested separately for each cross-sectional area, no additional test is
necessary. If not, and if it is required for bimetallic through connectors, additional tests
shall be made using the conductor having the highest temperature of the two conductors,
as reference conductor;
– if a type test for a range taking mechanical connector is passed on the biggest possible
conductor cross-sectional area, this result is also valid for similar connector designs with
the same material of the connector body but bigger outer diameter provided that the
design of the conductor clamping channel (inner diameter, shape, etc.), quantity and
design of clamping screws (torque, material, size, shear-off characteristic, etc.) are
identical;
– if a manufacturer can clearly demonstrate that common and relevant connector design
criteria were used for a family of connectors, conformity to this document is achieved by
successfully testing the largest, the smallest and two intermediate connector sizes;
exception no.1: for a family of connectors consisting of five sizes, only the largest
connector, the smallest connector, and one connector of a representative intermediate
size need to be tested;
exception no.2: for a family of connectors consisting of four sizes or less, only the
largest connector and the smallest connector need to be tested;

– if conformity to this document is achieved by successfully testing a connector on dry
conductor then approval is achieved for the same conductor used in an impregnated paper
insulated cable;
– for connectors where one or both sides are designed for a range of cross-sectional areas,
and a common clamping or crimping arrangement serves for the connection of the
different cross-sectional areas, then mechanical tests on conductors with the largest and
smallest cross-sectional areas shall be carried out according to Clause 7;
– if conformity to this document is achieved by successfully testing a mechanical connector
on round stranded aluminium conductors, this type test approval can be applied to solid
aluminium conductors of the same cross-sectional area(s);
– if conformity to this document is achieved by successful testing of a through connector,
this type test approval can apply to the barrel of a termination which uses the same design
criteria. Approval of the complete termination can be achieved if the termination
connection does not influence the barrel performance, proven through design parameters,
drawings or through thermal verification test;
– if conformity to this document is achieved by successfully testing a connector on a
conductor with water blocking, approval is achieved for the same conductor without any
water blocking but not for the same conductor with different types of water blocking.
6 Electrical tests
6.1 Installation
6.1.1 General
All conductors of the same cross-sectional area in the test loop shall be taken from the same
conductor length.
For each series of tests, six connectors shall be installed in accordance with the
manufacturer’s instructions, on a bare conductor or on a conductor that has had the insulation
removed before assembly, to form a test loop together with the corresponding reference
conductor.
For stranded conductors, potential differences between the strands at potential measuring
positions can cause errors in measuring electrical resistance. Equalizers according to
Annex A shall be used to overcome this problem and to ensure uniform current distribution in
the reference conductor and between connectors at the equalizer positions. The
recommended method is to prepare equalizers on the test loop before installing connectors.
The test loop shall be installed in a location where the air is calm.
The ambient temperature of the test location shall be between 15 °C and 30 °C.
For conductor cross-sectional areas above 1 000 mm , increasing the ambient temperature
range of the test location between 15 °C and 40 °C is allowed. At the end of the cooling phase
the ambient temperature shall be between 15 °C and 30 °C.
In the case of solid conductors, the potential measuring positions shall be as close as
possible to the connector in order to reduce l and l close to zero.
a b
The test loop may be of any shape according to Figures 2 or 3 provided that it is arranged in
such a way that there is no adverse effect from the floor, walls and ceiling, other test loops
and adjacent test branches.
To facilitate the short-circuit test, the loop may be disassembled as shown in Figure 2 b). In
this case, the sectioning connections shall not influence the temperatures of the test objects
during heating.
– 14 – IEC 61238-1-3:2018 © IEC 2018
Retightening of bolts or screws of the connectors under test is not permitted.
6.1.2 Through connectors and terminations
The test loop shown in Figure 2 indicates the dimensions that shall be used.
Where terminal lugs or mechanical connectors for terminal bars are to be tested, they shall be
bolted to linking bars in accordance with the manufacturer's instructions or the relevant
standards/specifications defining methods and instructions for fastening terminations. These
linking bars shall, at the point of connection, be of the same dimensions and thickness as the
palm, and also of the same material.
It may be necessary to adjust the thermal characteristics of the linking bar outside the point of
connection, to achieve the temperatures specified in 6.3.
For terminal lugs, the use of linking bars is the recommended test method although it is
alternatively possible to test terminal lugs with palms connected directly to palms.
If it is requested that the terminal lug test includes an evaluation of the performance of the
bolted palm when connected to a specified plant terminal, then the linking bar method shall be
used and the linking bar ends, or an intermediate piece, shall be defined and described in
material, size and surface coating.
NOTE Recommendations for testing cable terminal lugs for application in separable connectors, based on the
terminal lug method, are given in Annex H.
6.1.3 Branch connectors
When the branch connector is intended for a branch nominal cross-sectional area equal to the
main, or a cross-sectional area immediately above or below the main, it is treated as a
through connector between the main and the branch, the test method for through connectors
and Figures 2 a) or 2 b) are applicable. In other cases, the test loop shall be as shown in
Figure 3. Where a type of connector makes it necessary for the main conductor to be cut, that
part of the connector which acts as a through connector, shall also be tested as for through
connectors.
6.2 Measurements
6.2.1 General
Measurements shall be made at stages throughout the test according to Table 2.
NOTE Recommendations to decrease uncertainties of measurements are given in Annex C.
6.2.2 Electrical resistance measurements
The resistance measurements shall be made under steady temperature conditions of both the
test loop and test location. The ambient temperature shall be between 15 °C and 30 °C.
The recommended method is to pass a direct current of up to 10 % of the estimated heat
cycling current, through the connectors and the reference conductor, without significantly
increasing the temperature and to measure the potential difference between two specific
potential measuring positions. The ratio of potential difference and direct current is the
electrical resistance between those two positions.
To decrease the uncertainty of the resistance measurement, it is recommended that the direct
current is adjusted to the same value throughout the electrical test.

For branch conductors assembled in accordance with Figure 3, the whole of the measuring
current shall flow through that part of the connector whose potential difference is being
measured. Switches or disconnecting terminals may be provided for this purpose.
Thermoelectric voltages may affect the uncertainty of low resistance measurements (of the
order of 10 µΩ). If this is suspected, the recommended method is to take two resistance
measurements with the direct measuring current reversed between readings. The mean of the
two readings is then the actual resistance of the sample.
The potential measuring positions shall be as indicated in Figure 4 and Annex B. The various
lengths shall be measured individually to enable the actual connector resistances to be
determined. The temperature of connector and reference conductor shall be recorded when
resistance measurements are made. For direct comparison, the resistance values shall be
corrected to 20 °C. Information on the recommended method is also given in Annex B.
Temperature measurements at these positions shall be made during the heat cycling test.
Indirect resistance readings:
– voltage measurements shall have a device uncertainty within ± 0,5 % or ± 10 µV, by taking
the greater value;
– current measurements shall have a device uncertainty within ± 0,5 % or ± 0,1 A, by taking
the greater value.
Direct resistance readings:
Resistance measurements shall have a device uncertainty within ± 1 % or ± 0,5 µΩ,
whichever is the greater when the instrument is calibrated against a certified standard
resistance.
6.2.3 Temperature measurements
Temperatures of both connectors and reference conductors shall be measured at the
positions indicated in Figure 4. The recommended method of temperature measurement is to
use thermocouples. The temperature measurements shall have a device uncertainty within
± 2 K.
6.3 Heat cycling
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