National foreword

This British Standard is the UK implementation of EN IEC 60851‑5:2026. It is identical to IEC 60851‑5:2026. It supersedes BS EN 60851‑5:2008+A2:2019, which will be withdrawn on 31 October 2029.

Contractual and legal considerations

This publication has been prepared in good faith, however no representation, warranty, assurance or undertaking (express or implied) is or will be made, and no responsibility or liability is or will be accepted by BSI in relation to the adequacy, accuracy, completeness or reasonableness of this publication. All and any such responsibility and liability is expressly disclaimed to the full extent permitted by the law.

This publication is provided as is, and is to be used at the recipient’s own risk.

The recipient is advised to consider seeking professional guidance with respect to its use of this publication.

This publication is not intended to constitute a contract. Users are responsible for its correct application.

Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 October 2026.

This European Standard was approved by CENELEC on 17 September 2026. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czechia, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and United Kingdom.

European foreword

The text of document 55/2089/FDIS, future edition 5 of IEC 60851‑5, prepared by TC 55 "Winding wires" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN IEC 60851‑5:2026.

The following dates are fixed:

This document supersedes EN 60851‑5:2008 and all of its amendments and corrigenda (if any).

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

Any feedback and questions on this document should be directed to the users’ national committee. A complete listing of these bodies can be found on the CENELEC website.

Endorsement notice

The text of the International Standard IEC 60851‑5:2026 was approved by CENELEC as a European Standard without any modification.

In the official version, for Bibliography, the following notes have to be added for the standard indicated:

FOREWORD

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.
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.
IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user.
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.
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.
All users should ensure that they have the latest edition of this publication.
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.
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.
IEC draws attention to the possibility that the implementation of this document may involve the use of (a) patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which may be required to implement this document. However, implementers are cautioned that this may not represent the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC shall not be held responsible for identifying any or all such patent rights.

IEC 60851-5 has been prepared by IEC technical committee 55: Winding wires. It is an International Standard.

This fifth edition cancels and replaces the fourth edition published in 2008, Amendment 1:2011 and Amendment 2:2019. This edition constitutes a technical revision.

This edition includes the following significant technical changes with respect to the previous edition:

Subclauses 5.3.1 and 5.3.2 modified to expand the conductor size range for the loads applied during cylinder method testing for dielectric breakdown voltage of enameled wires and for fully insulated wires.
Addition of subclause 6.5 for inline continuity testing of rectangular wire (under consideration).

The text of this International Standard is based on the following documents:

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/publications.

A list of all the parts in the IEC 60851 series, under the general title Winding wires - Test methods, can be found on the website.

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, or
revised.

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. The series has three groups describing:

winding wires - test methods (IEC 60851);
specifications for particular types of winding wires (IEC 60317);
packaging of winding wires (IEC 60264).

1 Scope

This part of IEC 60851 specifies the following tests:

Test 5: Electrical resistance;
Test 13: Breakdown voltage;
Test 14: Continuity of insulation;
Test 19: Dielectric dissipation factor;
Test 23: Pin hole.

For definitions and general notes on methods of test, Clause 3 of IEC 60851‑1:2021 applies.

This part of IEC 60851 also specifies methods for determining the dissipation factor of enamelled winding wire, provided in Annex A.

2 Normative references

3 Terms and definitions

4 Test 5: Electrical resistance

5 Test 13: Breakdown voltage

5.1 Principle

5.2 Equipment

5.3 Enamelled round wire

5.4 Enamelled round wire with a nominal conductor diameter over 0,100 mm up to and including 2,500 mm, grade 1 to grade 3

5.5 Round wire with a nominal conductor diameter over 2,500 mm

5.6 Fibre wound round wire

5.7 Rectangular wire

5.8 Overview of breakdown voltage specimen preparation

6 Test 14: Continuity of insulation (applicable to enamelled round and tape wrapped round wire)

6.1 General

6.2 Low-voltage continuity (nominal conductor diameter up to and including 0,050 mm, grade 1 to grade 3)

6.3 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)

6.4 Inline high-voltage continuity (wires in accordance with grade of FIW 3 to FIW 9 with nominal conductor diameter over 0,035 mm up to and including 1,600 mm)

6.5 Inline high-voltage continuity (enamelled rectangular wire)

7 Test 19: Dielectric dissipation factor (applicable to enamelled wire and bunched wire)

7.1 Principle

7.2 Equipment

7.3 Specimen

7.4 Procedure

7.5 Result

8 Test 23: Pin hole test

Bibliography