IEC 60851-1:2021

IEC 60851-1 ®
Edition 3.0 2021-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Winding wires – Test methods –
Part 1: General
Fils de bobinage – Méthodes d'essai –
Partie 1: Généralités
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IEC 60851-1 ®
Edition 3.0 2021-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Winding wires – Test methods –
Part 1: General
Fils de bobinage – Méthodes d'essai –
Partie 1: Généralités
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.060.10 ISBN 978-2-8322-9882-4
– 2 – IEC 60851-1:2021 © IEC 2021
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions and general notes on methods of test . 6
3.1 Terms and definitions . 6
3.2 General notes on methods of test . 8
Annex A (informative) Contents of IEC 60851-2 to IEC 60851-6 with indication of tests . 10
A.1 General . 10
A.2 IEC 60851-2 . 10
A.3 IEC 60851-3 . 11
A.4 IEC 60851-4 . 12
A.5 IEC 60851-5 . 13
A.6 IEC 60851-6 . 14
Bibliography . 15

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
WINDING WIRES – TEST METHODS –

Part 1: General
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
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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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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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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.
IEC 60851-1 has been prepared by IEC technical committee 55: Winding wires. It is an
International Standard.
This third edition cancels and replaces the second edition published in 1996, and its
amendment 1:2003 and amendment 2:2009. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) revision to Clause 2 to update the list of normative references;
b) revision to 3.2 atmospheric conditions for testing;
c) addition to 3.2 with remarks concerning frequency and management of tests;
d) revision to Annex A to update the contents list of IEC 60851 series of tests.

– 4 – IEC 60851-1:2021 © IEC 2021
The text of this International Standard is based on the following documents:
FDIS Report on voting
55/1913/FDIS 55/1916/RVD
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 International Standard is English.
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.
Annex A is for information only.
A list of all parts in the IEC 60851 series, published under the general title Winding wires – Test
methods, 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.
INTRODUCTION
This Part of IEC 60851 forms an element of a series of standards which deals with insulated
wires used for windings in electrical equipment. It is composed of the following series:
1) Winding wires – Test methods (IEC 60851 series);
2) Specifications for particular types of winding wires (IEC 60317 series);
3) Packaging of winding wires (IEC 60264 series).

– 6 – IEC 60851-1:2021 © IEC 2021
WINDING WIRES – TEST METHODS –

Part 1: General
1 Scope
This part of IEC 60851 specifies the general notes on methods of test for winding wires. It also
gives the definitions for terms used in IEC 60851 (all parts). A survey of the contents of
IEC 60851-2 to IEC 60851-6 is given in Annex A.
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 60317 (all parts), Specifications for particular types of winding wires
IEC 60851-2:2009 , Winding wires – Test methods – Part 2: Determination of dimensions
IEC 60851-2:2009/AMD1:2015
IEC 60851-2:2009/AMD2:2019
IEC 60851-3:2009 , Winding wires – Test methods – Part 3: Mechanical properties
IEC 60851-3:2009/AMD1:2013
IEC 60851-3:2009/AMD2:2019
IEC 60851-4:2016, Winding wires – Test methods – Part 4: Chemical properties
IEC 60851-5:2008 , Winding wires – Test methods – Part 5: Electrical properties
IEC 60851-5:2008/AMD1:2011
IEC 60851-5:2008/AMD2:2019
IEC 60851-6:2012, Winding wires – Test methods – Part 6: Thermal properties
3 Terms, definitions and general notes on methods of test
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
____________
A consolidated version of IEC 60851-2:2009 and its amendments exists.
A consolidated version of IEC 60851-3:2009 and its amendments exists.
A consolidated version of IEC 60851-5:2008 and its amendments exists.

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
3.1.1
bonding layer
material which is deposited on an enamelled wire and which has the specific function of bonding
wires together
3.1.2
bunched wire
winding wire consisting of a quantity of small diameter insulated wires laid-up together without
predetermined geometrical position and with or without additional covering
3.1.3
class
thermal performance of a wire expressed by the temperature index and the heat shock
temperature
3.1.4
coating
material which is deposited on a conductor or wire by suitable means and then dried and/or
cured
3.1.5
conductor
bare metal after removal of the insulation
3.1.6
covering
material which is wound, wrapped or braided around a bare or insulated conductor
3.1.7
crack
opening in the insulation which exposes the conductor to view at the stated magnification
3.1.8
cure
process of converting a reactive compound into a stable, usable condition by polymerization
(polycondensation and polyaddition) and/or crosslinking
[SOURCE: IEC 60050-212:2010, 212-13-07, modified – At the beginning of the definition,
"convert a reactive compound" has been replaced by "process of converting a reactive
compound" to define the term as a process.]
3.1.9
dual coating
insulation composed of two different materials, an underlying and a superimposed coating
3.1.10
enamelled wire
wire coated with an insulation of cured resin
3.1.11
grade
range of increase in dimension of the wire due to insulation

– 8 – IEC 60851-1:2021 © IEC 2021
3.1.12
insulation
coating or covering of the conductor with the specific function of withstanding voltage
3.1.13
nominal conductor dimension
designation of the conductor size in accordance with the specification sheet in the IEC 60317
series
3.1.14
sole coating
insulation composed of one material
3.1.15
winding wire
wire used for winding a coil to provide a magnetic field
3.1.16
wire
conductor coated or covered with an insulation
3.1.17
normal vision
20/20 vision, with corrective lenses, if necessary
3.1.18
zero-defect wire
winding wire that exhibits no electrical discontinuities when tested under specific conditions
3.2 General notes on methods of test
Unless otherwise specified, all tests shall be carried out at a temperature from 15 °C to 40 °C
and a relative humidity of 25 % to 75 %. Before measurements are made, the specimens shall
be preconditioned under these atmospheric conditions for a time sufficient to allow the wire to
reach stability.
The wire to be tested shall be removed from the packaging in such a way that the wire will not
be subjected to tension or to unnecessary bends. Before each test, sufficient wire shall be
discarded to ensure that any damaged wire is not included in the test specimens.
Normally, all mandatory requirements for a method of test are given in the description, and
diagrams are intended only to illustrate one possible arrangement for conducting the test.
In case of inconsistencies between the IEC 60317 specification sheet and this document, the
specification sheet shall prevail.
When the test is restricted only to certain types of winding wires, this is specified with the test.
Those tests of IEC 60851-2, IEC 60851-3, IEC 60851-4, IEC 60851-5 and IEC 60851-6 which
in Annex A are marked with an asterisk are periodic conformance tests. These tests are carried
out at a frequency agreed upon request of the end user.
The test numbers used in IEC 60851-2, IEC 60851-3, IEC 60851-4, IEC 60851-5 and
IEC 60851-6 correspond with the clause numbers in the IEC 60317 series.

IEC winding wire standards do not specify how to deal with the management of tests (routine
versus non-routine/periodic). These are certification issues not governed by the standards. In
some countries, there are local rules that apply, but in general, decisions are taken by
agreement between customer and supplier.
The scope of IEC standards encompasses only the product requirements and does not extend
to the management of certification matters or supplier-customer agreements.

– 10 – IEC 60851-1:2021 © IEC 2021
Annex A
(informative)
Contents of IEC 60851-2 to IEC 60851-6 with indication of tests
A.1 General
The tables of contents as given in Clause A.2 to Clause A.6 are not exhaustive.
A.2 IEC 60851-2
The contents shown below refers to IEC 60851-2:2009, IEC 60851-2:2009/AMD1:2015 and
IEC 60851-2:2009/AMD2:2019.
1 Scope
2 Normative references
3 Test 4: Dimensions
3.1 Equipment
3.1.1 Round and rectangular wire
3.1.2 Bunched wire
3.2 Procedure
3.2.1 Conductor dimension
3.2.1.1 Round wire
3.2.1.2 Rectangular wire
3.2.2 Out-of-roundness of the conductor
3.2.3 Rounding of corners of rectangular wire
3.2.4 Increase in dimension due to the insulation
3.2.4.1 Round wire
3.2.4.2 Rectangular wire
3.2.5 Overall dimension
3.2.5.1 Round wire
3.2.5.2 Rectangular wire
3.2.5.3 Bunched wire
3.2.6 Increase in diameter due to the bonding layer of enamelled round wire
3.2.7 Increase in dimensions due to the bonding layer of enamelled rectangular wire
Annex A (informative)
A.3 IEC 60851-3
The contents shown below refers to IEC 60851-3:2009, IEC 60851-3:2009/AMD1:2013 and
IEC 60851-3:2009/AMD2:2019.
1 Scope
2 Normative references
3 Test 6: Elongation
3.1 Elongation at fracture
3.2 Tensile strength
4 Test 7: Springiness
4.1 Round wire with a nominal conductor diameter from 0,080 mm up to and including
1,600 mm
4.2 Round wire with a nominal conductor diameter over 1,600 mm and rectangular wire
5 Test 8: Flexibility and adherence
5.1 Mandrel winding test
5.1.1 Round wire
5.1.2 Rectangular wire
5.1.3 Covered bunched wire
5.2 Stretching test (applicable to enamelled round wire with a nominal conductor diameter
over 1,600 mm)
5.3 Jerk test (applicable to enamelled round wire with a nominal conductor diameter of up
to and including 1,000 mm)
5.4 Peel test (applicable to enamelled round wire with a nominal conductor diameter of over
1,000 mm)
5.5 Adherence test
5.5.1 Enamelled rectangular wire
5.5.2 Impregnated fibre covered round and rectangular wire
5.5.3 Fibre covered enamelled round and rectangular wire
5.5.4 Tape wrapped round and rectangular wire (for adhesive tape only)
6 Test 11*: Resistance to abrasion (applicable to enamelled round wire)
7 Test 18: Heat or solvent bonding (applicable to enamelled round wire with a nominal
conductor diameter over 0,050 mm up to and including 2,000 mm and to enamelled
rectangular wire)
7.1 Vertical bond retention of a helical coil
7.2 Bond strength of a twisted coil
7.3 Enamelled rectangular wire heat bonding
Annex A (informative) – Bond strength of heat bonding wires
Annex B (informative) – Friction test methods

– 12 – IEC 60851-1:2021 © IEC 2021
A.4 IEC 60851-4
The contents shown below refers to IEC 60851-4:2016.
1 Scope
2 Normative references
3 Test 12*: Resistance to solvents (applicable to enamelled round wire with a nominal
conductor diameter of over 0,250 mm and to enamelled rectangular wire)
3.1 Equipment
3.2 Procedure
4 Test 16*: Resistance to refrigerants (applicable to enamelled round wire)
4.1 Extraction
4.2 Breakdown voltage
5 Test 17: Solderability (applicable to enamelled round wire and bunched wire)
5.1 Equipment
5.2 Procedure
6 Test 20*: Resistance to hydrolysis and to transformer oil (applicable to enamelled wire)
6.1 General
6.2 Round wire
6.3 Rectangular wire
Annex A (informative) – Alternative refrigerants to monochloro-difluoromethane

A.5 IEC 60851-5
The contents shown below refers to IEC 60851-5:2008, IEC 60851-5:2008/AMD1:2011 and
IEC 60851-5:2009/AMD2:2019.
1 Scope
2 Normative references
3 Test 5: Electrical resistance
4 Test 13: Breakdown voltage
4.1 Principle
4.2 Equipment
4.3 Enamelled round wire
4.4 Enamelled round wire with a nominal conductor diameter over 0,100 mm and up to and
including 2,500 mm, grade 1 to grade 3
4.5 Round wire with a nominal conductor diameter over 2,500 mm
4.6 Fibre wound round wire
4.7 Rectangular wire
5 Test 14: Continuity of insulation (applicable to enamelled round and tape wrapped round
wire)
5.1 General
5.2 Low-voltage continuity (nominal conductor diameter up to and including 0,050 mm,
grade 1 to grade 3)
5.3 High-voltage continuity (nominal conductor diameter over 0,050 mm up to and including
1,600 mm, grade 1 to grade 3, and over 0,035 mm, up to and including 1,600 mm, grade
3 of FIW 3 to FIW 9)
5.4 Inline high-volt
...