IEC 60626-1:2023

IEC 60626-1
®

Edition 4.0 2023-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE


Combined flexible materials for electrical insulation –
Part 1: Definitions and general requirements

Matériaux combinés souples destinés à l'isolement électrique –
Partie 1: Définitions et exigences générales
IEC 60626-1:2023-08(en-fr)

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IEC 60626-1

®


Edition 4.0 2023-08




INTERNATIONAL



STANDARD




NORME



INTERNATIONALE











Combined flexible materials for electrical insulation –

Part 1: Definitions and general requirements




Matériaux combinés souples destinés à l'isolement électrique –

Partie 1: Définitions et exigences générales















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE


INTERNATIONALE





ICS 29.035.01  ISBN 978-2-8322-7361-6




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 – IEC 60626-1:2023 © IEC 2023
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Designations . 8
4.1 Designation – Product . 8
4.2 Designation – Testing . 10
4.2.1 General testing . 10
4.2.2 Mechanical testing . 10
4.2.3 Electrical testing . 10
4.2.4 Thermal/Chemical testing . 10
5 General requirements . 10
5.1 Supply of material . 10
5.2 Consignment requirements . 10
5.3 Roll requirements . 10
5.4 Contamination requirements . 10
5.5 Warp requirements . 10
6 Dimensions. 10
7 Joins . 11
8 Conditions of supply . 11
8.1 Roll form . 11
8.2 Sheet form . 11
8.3 Packaging . 11
8.4 Labelling . 11
8.5 Special conditions of supply . 11
Bibliography . 12

Table 1 – Commonly used flexible materials . 9

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IEC 60626-1:2023 © IEC 2023 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

COMBINED FLEXIBLE MATERIALS FOR ELECTRICAL INSULATION –

Part 1: Definitions and general requirements

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
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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) 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 60626-1 has been prepared by IEC technical committee 15: Solid electrical insulating
materials. It is an International Standard.
This fourth edition cancels and replaces the third edition published in 2009. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) the materials available for use within this series of standards have been updated;
b) a framework has been created to allow test methods beyond those used for quality control
specifications to allow for testing for qualification purposes.

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– 4 – IEC 60626-1:2023 © IEC 2023
The text of this International Standard is based on the following documents:
Draft Report on voting
15/1009/FDIS 15/1016/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/publications.
A list of all parts in the IEC 60626 series, published under the general title Combined flexible
materials for electrical insulation, 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 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.

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IEC 60626-1:2023 © IEC 2023 – 5 –
INTRODUCTION
This document is one of a series which deals with combined flexible materials consisting of two
or more different insulating materials laminated together. The components of the combined
materials are plastic films and/or fibrous materials such as papers, woven or non-woven fabrics,
impregnated or not impregnated. This document does not include mica papers used as primary
component, which are covered by the IEC 60371 series, but insulation materials based on mica
can be used as component of a combined flexible material.
This series consist of three parts describing:
Part 1: Definitions and general requirements (IEC 60626-1);
Part 2: Methods of test (IEC 60626-2);
Part 3: Specifications for individual materials (IEC 60626-3).

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– 6 – IEC 60626-1:2023 © IEC 2023
COMBINED FLEXIBLE MATERIALS FOR ELECTRICAL INSULATION –

Part 1: Definitions and general requirements



1 Scope
This part of IEC 60626 contains the definitions related to and the general requirements to be
fulfilled by combined flexible materials for electrical insulation. This document does not include
mica papers used as a primary component, which are covered by the IEC 60371 series, but
insulation materials based on mica paper can be used as component of a combined flexible
material. Materials which conform to this specification meet established levels of performance.
However, the selection of material by a user for a specific application is based on the actual
requirements necessary for adequate performance in that application and not based on this
specification alone.
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 60371-3-2, Insulating materials based on mica – Part 3: Specifications for individual
materials – Sheet 2: Mica paper
IEC 60371-3-4, Specification for insulating materials based on mica – Part 3: Specifications for
individual materials – Sheet 4: Polyester film-backed mica paper with B-stage epoxy resin
binder
IEC 60371-3-5, Insulating materials based on mica – Part 3: Specifications for individual
materials – Sheet 5: Glass-backed mica paper with and epoxy resin binder for post-
impregnation (VPI)
IEC 60371-3-6, Specification for insulating materials based on mica – Part 3: Specifications for
individual materials – Sheet 6: Glass-backed mica paper with B-stage epoxy resin binder
IEC 60554-3-1, Specification for cellulosic papers for electrical purposes – Part 3-1:
Specifications for individual materials – General purpose electrical paper
IEC 60626-3, Combined flexible materials for electrical insulation – Part 3: Specifications for
individual materials
IEC 60641-3-2:2007, Pressboard and presspaper for electrical purposes – Part 3:
Specifications for individual materials – Sheet 2: Requirements for presspaper types P.2.1,
P4.1, P4.2, P4.3 and P6.1
IEC 60674-3-2, Specification for plastic films for electrical purposes – Part 3: Specifications for
individual materials – Sheet 2: Requirements for balanced biaxially oriented Polyethylene
Terephthalate (PET) films used for electrical insulation
IEC 60674-3-4, Plastic films for electrical purposes – Part 3: Specifications for individual
materials – Sheets 4: Polyimide films used for electrical insulation

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IEC 60626-1:2023 © IEC 2023 – 7 –
IEC 60674-3-8, Plastic films for electrical purposes – Part 3: Specifications for individual
materials – Sheet 8: Balanced biaxially oriented polyethylene naphthalate (PEN) films used for
electrical insulation
IEC 60819-3-1, Non-cellulosic papers for electrical purposes – Part 3: Specifications for
individual materials – Sheet 1: Filled glass paper
IEC 60819-3-2, Non-cellulosic papers for electrical purposes – Part 3: Specifications for
individual materials – Sheet 2: Hybrid inorganic- organic paper
IEC 60819-3-3, Non-cellulosic papers for electrical purposes – Part 3: Specifications for
individual materials – Sheet 3: Unfilled aramid (aromatic polyamide) papers
IEC 60819-3-4:2011, Non-cellulosic papers for electrical purposes – Part 3: Specifications for
individual materials – Sheet 4: Aramid fibre paper containing not more than 50 % of mica
particles
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
full width material
material of production width, for example about 1 m, as ordered
3.2
slit material
tape
material cut from full width material
3.3
duplex material
laminate consisting of two layers of insulating materials
3.4
triplex material
laminate consisting of three layers of insulating materials
3.5
quadruplex material
laminate consisting of four layers of insulating materials

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– 8 – IEC 60626-1:2023 © IEC 2023
4 Designations
4.1 Designation – Product
Particular types of combined flexible insulating materials can be designated by using the
relevant combinations of code letters for the form and nature of the main components,
separated by a hyphen.
EXAMPLES: F - PI,
 C - G.
The more commonly used materials are listed in Table 1, with their corresponding specifications
that shall be used when available. Other combinations of combined flexible materials for use
as electrical insulation are possible.
Specific characteristics of a particular combined material (duplex, triplex or quadraplex),
particular characteristics of the basic material, impregnating material, bonding agent, etc.) are
described by additional data following the designation in Table 1.
Example for designation:
P-C/F-PET, is a layer of paper consisting of cellulose, laminated with a film consisting of
polyethylene terephthalate.
In some cases, the identification of specific characteristics such as the following can be useful:
– Absorbent - porous Calendered type
– Lengthwise oriented Lengthwise reinforced
– Creped Embossed
– Varnished Impregnated
NOTE This list is for guidance only and is not limiting. Code designations are in accordance with ISO standards
such as ISO 1043-1.
Detailed specifics regarding commonly used combined flexible materials are provided in
IEC 60626-3. For these constructions, the following nomenclature shall be used:
IEC 60626-3, sheet number, layer descriptions, total thickness
For example, from Sheet 112, the following is a description of one such product:
IEC 60626-3, Sheet 112, P-C/F-PET/P-C, 0,15 mm
For constructions for which there is no detail provided in IEC 60626-3, the following
nomenclature shall be used:
2
IEC 60626-1, layer descriptions, thickness (micrometers) or grammage (g/m ) of each layer.
2
For simplicity, the micrometers will be represented by µ and the g/m will be represented by g.
For example, for a combined flexible material using aramid paper and polyethylene naphthalate
film in a triplex construction would be listed as:
IEC 60626-1, P-PAa/F-PEN/P-PAa, 50µ/80µ/50µ

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IEC 60626-1:2023 © IEC 2023 – 9 –
For constructions with added functional coatings, the following nomenclature shall be used:
IEC 60626-1, layer descriptions including coatings, thickness (micrometers) or grammage
2 2
(g/m ) of each layer. For simplicity, the micrometers will be represented by µ and the g/m will
be represented by g.
IEC 60626-1, FC-B-UP/P-PET/F-PET/P-PET/FC-B-UP, 10g/50µ/80µ/50µ/10g
In this example, there is a material sheet 502 in IEC 60626-3 for the uncoated combined flexible
material, but since this construction is more detailed, this naming nomenclature shall be used.
Table 1 – Commonly used flexible materials
Form of Code Nature of the component Code IEC normative
component designation designation reference
Film F Polyethylene terephthalate PET 60674‑3‑2

Polyethylene naphthalate PEN 60674‑3‑8

Polyimide PI 60674‑3‑4

Polyether Ether Ketone PEEK n. a.

Polyphenylene Sulfide PPS n. a
Paper and P Cellulose paper C 60554‑3; 60641‑3‑2

non-woven
Aramid paper (Aromatic Polyamide) PAa 60819‑3‑3
fabric and

mats
Aramid fibre/mica paper PAa-Mi 60819‑3‑4

Polyethylene terephthalate non woven PET n. a.

Filled glass paper FG 60819‑3‑1

Hybrid inorganic/organic paper H 60819‑3‑2

Mica paper, reinforced mica paper Mi 60371‑3‑2

Materials based on mica and epoxy MiEP 60371‑3‑4;
60371‑3‑5; 60371‑3‑6
Woven C Cellulose C n. a.

fabrics
Glass G n. a.

Polyethylene terephthalate PET n. a.
Adhesive A Thermoplastic Tp n. a

Thermosetting Ts n. a
Coating FC B-Staged epoxy B-EP n. a.

B-Staged unsaturated polyester B-UP n. a

a
C-Staged functional coatings n. a.
C-
The list of normative references is extensive because, in order to obtain a combination of two or more materials
for electrical insulation, it is necessary that those base materials (paper, film, etc) shall conform to the
requirements set forth, in the appropriate specification of the base material alone, for that purpose. This rule shall
be applied also in the development of new possible combinations; to this end, specifications of materials not
actually used, but referenced, can be eligible for future developments.
NOTE n. a. = not available
a
These coatings can be any polymer such as epoxy, unsaturated polyester, silicone, fluoropolymer, etc.
Designations for these coatings are provided in ISO 1043-1.

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– 10 – IEC 60626-1:2023 © IEC 2023
4.2 Designation – Testing
For materials covered by this document, test methods are provided in IEC 60626-2, and these
tests in the future will be arranged into these four categories of tests, with the expectations that
the properties evaluated for quality control purposes will be used for specification sheets as
outlined in IEC 60626-3. The tests described in IEC 60626-2 under additional testing are
designed to be appropriate tests for these combined flexible materials but are not typically used
as part of a quality control program.
4.2.1 General testing
– Testing for quality control purposes
4.2.2 Mechanical testing
– Testing for quality control purposes
– Additional mechanical testing
4.2.3 Electrical testing
– Testing for quality control purposes
– Additional electrical testing
4.2.4 Thermal/Chemical testing
– Testing for quality control purposes
– Additional thermal/chemical testing
5 General requirements
5.1 Supply of material
The material may be delivered in sheets cut to length or in rolls (either as full width or slit
materials).
5.2 Consignment requirements
All materials in any one consignment shall be consistent and have properties within the limits
of this standard throughout the whole sheet or throughout the whole length of each roll. The
surface shall be uniform, reasonably smooth and reasonably free from defects such as bubbles,
pin holes, creases and flaws.
5.3 Roll requirements
When delivered in rolls, it shall be capable of being unrolled without damage.
5.4 Contamination requirements
The combined materials shall be free of conducting particles and other undesirable inclusions.
5.5 Warp requirements
Materials delivered in sheets cut to length shall be reasonably free from warp.
NOTE After bonding, materials produced in roll form often assume a "roll set" which depends upon time and
temperature of storage. Sheets made from such rolls will need appreciable time before warp is relieved.
6 Dimensions
Thickness and thickness tolerances are dealt with in IEC 60626-3. Other dimensions and
tolerances shall be agreed by the purchaser and the supplier.

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IEC 60626-1:2023 © IEC 2023 – 11 –
7 Joins
For material in roll form, the allowable frequency of joins, the details of their construction, and
identification shall be agreed by the purchaser and the supplier.
8 Conditions of supply
8.1 Roll form
Material in roll form shall be supplied on cardboard roll or other suitable core. The inner diameter
of the core shall be agreed by purchaser and supplier, and it should preferably be 55 mm,
76 mm,150 mm, or 152 mm.
8.2 Sheet form
Material in sheet form shall be supplied in stacks.
8.3 Packaging
The material shall be placed in a packing which ensures adequate protection during transport,
handling and storage.
8.4 Labelling
Each unit pack, and each package containing a number of unit packs, shall have the following
information clearly and indelibly marked on it:
a) the reference to this standard;
b) the designation of the type, in accordance with clause 2;
c) for materials delivered in rolls: the width and the length or weight of each roll;
d) for materials delivered in sheets: the dimensions of the sheets and the number of sheets in
a stack or the mass of the stack;
e) the nominal thickness of the material;
f) the number of rolls or stacks in a larger package;
g) the date of manufacturing;
h) information about joins as required by IEC 60626-3.
8.5 Special conditions of supply
Any special conditions of supply, such as requirements regarding shelf life, shall be agreed by
the purchaser and the supplier.

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– 12 – IEC 60626-1:2023 © IEC 2023
Bibliography
IEC 60371 (all parts), Insulating materials based on mica
IEC 60554-1:1977, Specification for cellulosic papers for electrical purposes – Part 1:
Definitions and general requirements
IEC 60641-1:2007, Pressboard and presspaper for electrical purposes – Part 1: Definitions and
general requirements.
IEC 60626-2, Combined flexible materials for electrical insulation – Part 2: Methods of test
IEC 60674-1:1980, Specification for plastic films for electrical purposes – Part 1: Definitions
and general requirements
IEC 60819-1:2009, Non-cellulosic papers for electrical purposes – Part 1: De
...