IEC 61061-1:2006
(Main)Non-impregnated densified laminated wood for electrical purposes - Part 1: Definitions, designation and general requirements
Non-impregnated densified laminated wood for electrical purposes - Part 1: Definitions, designation and general requirements
IEC 61061-1:2006 includes the definitions required for the understanding of all three parts of the standard, the designation of the material types and the general requirements applicable to non-impregnated densified laminated wood for electrical purposes includes the definitions required for the understanding of all three parts of the standard, the designation of the material types and the general requirements applicable to non-impregnated densified laminated wood for electrical purposes. This specification is intended to cover only sheets and rings of nominal thicknesses between 6 mm and 100 mm, inclusive. The main changes from the previous edition are as follows:
- addition of application use and safety statements;
- redefinition of ring and sheet;
- appropriate additions to the subclauses;
- reformatting of text to bring it in line with the IEC document format.
Stratifiés de bois densifié, non imprégnés, à usages électriques - Partie 1: Définitions, désignation et exigences générales
La CEI 61061-1:2006 comprend les définitions nécessaires à la compréhension des trois parties de la norme, la désignation des types de matériaux et les exigences générales applicables aux stratifiés de bois densifié, non imprégnés, à usages électriques. La présente spécification est prévue pour s'appliquer uniquement aux planches et aux anneaux d'épaisseurs nominales comprises entre 6 mm et 100 mm inclus. Les principales modifications suivantes ont été apportées par rapport à l'édition précédente:
- ajout des cas d'emploi et des déclarations de sécurité;
- redéfinition de l'anneau et de la planche;
- ajouts pertinents aux paragraphes;
- remise en forme du texte pour l'aligner sur le format actuel des documents CEI.
General Information
- Status
- Published
- Publication Date
- 24-Oct-2006
- Technical Committee
- TC 15 - Solid electrical insulating materials
- Drafting Committee
- WG 6 - TC 15/WG 6
- Current Stage
- PPUB - Publication issued
- Start Date
- 25-Oct-2006
- Completion Date
- 15-Mar-2007
Relations
- Effective Date
- 05-Sep-2023
Overview
IEC 61061-1:2006 is an international standard developed by the International Electrotechnical Commission (IEC) that specifies the definitions, designation, and general requirements for non-impregnated densified laminated wood used for electrical purposes. This Part 1 of the IEC 61061 series serves as the foundational document for understanding the material types covered in the subsequent parts.
The standard applies to sheets and rings of laminated wood with nominal thicknesses ranging from 6 mm to 100 mm. It ensures that the laminated wood meets performance and safety requirements suitable for electrical insulation applications, especially where resistance to transformer oils and mechanical integrity are critical.
Key updates in this edition include:
- Addition of application use and safety statements
- Redefinition of ring and sheet classifications
- Additions to detailed technical subclauses
- Reformatting to align with current IEC document structure
Key Topics
Definitions and Terms
Clear terminology is provided for:
- Veneer: individual plies of wood, typically not thicker than 2.5 mm before pressing
- Non-impregnated densified laminated wood: layers of wood veneers bonded with thermosetting synthetic resin under heat and pressure, without impregnation
- Sheet and ring forms: sheets have parallel or crosswise veneer arrangements; rings may be formed by cutting or pressing veneers in tangential or angled layouts
- Directions "A" and "B" define orthogonal planes in laminated sheets
Material Designation
The standard outlines a structured designation system based on:
- Shape (Sheet or Ring)
- IEC standard number (61061)
- Veneer arrangement type (P for parallel, C for crosswise, T for tangential, A for 45° angled)
- Density class (1 to 4 indicating increasing apparent density ranges from 0.7 to 1.3 g/cm³)
- Wood type (B for birch, M for maple, R for beech)
- Dimensions (thickness, width, length for sheets; thickness, radial width, outer diameter for rings)
General Requirements
The standard mandates:
- Use of wood veneers and resin resistant to transformer oils, ensuring no detrimental effects during operation
- Free from defects such as diseased areas or electrically conductive inclusions; fibre direction must be controlled
- Finished sheets must be flat, smooth, with tightly butted veneer joints; rings must also have close joints free from significant gaps
- Thickness tolerances and flatness requirements as per referenced test methods (IEC 61061-2 and IEC 61061-3)
- Material machinability ensuring no chipping, splitting, or cracking when processed carefully
Safety and Application Statements
Users must ensure safe handling, use, and application of these materials. Selection should be based on specific application requirements beyond just compliance with the specification.
Applications
Non-impregnated densified laminated wood is widely used in electrical insulation systems, notably in:
- Transformers and switchgear components where mechanical strength and electrical insulation are critical
- Components exposed to transformer oils requiring material compatibility and chemical resistance
- Insulation sheets and rings that support electrical devices by providing compression strength and thermal stability
- High voltage equipment laminations where dimensional stability and resistance to oil ingress are required
This standard supports manufacturing and quality assurance processes, helping manufacturers and purchasers specify and verify appropriate laminated wood products for electrical uses.
Related Standards
IEC 61061-1:2006 is part of a series addressing densified laminated wood for electrical purposes:
- IEC 61061-2: Methods of test for non-impregnated densified laminated wood
- IEC 61061-3: Specifications for individual materials within this product group
- IEC 60296: Standard on unused mineral insulating oils for transformers and switchgear, referenced for material compatibility
- Other IEC standards associated with solid electrical insulating materials
These standards together provide a comprehensive framework governing the production, testing, and use of non-impregnated densified laminated wood in electrical engineering applications.
Keywords: IEC 61061-1:2006, non-impregnated densified laminated wood, electrical insulation, laminated wood sheets, laminated wood rings, electrical insulation materials, IEC standards, transformer insulation, laminated wood designation, laminated wood requirements
IEC 61061-1:2006 - Non-impregnated densified laminated wood for electrical purposes - Part 1: Definitions, designation and general requirements Released:10/25/2006 Isbn:2831888743
IEC 61061-1:2006 - Non-impregnated densified laminated wood for electrical purposes - Part 1: Definitions, designation and general requirements
Frequently Asked Questions
IEC 61061-1:2006 is a standard published by the International Electrotechnical Commission (IEC). Its full title is "Non-impregnated densified laminated wood for electrical purposes - Part 1: Definitions, designation and general requirements". This standard covers: IEC 61061-1:2006 includes the definitions required for the understanding of all three parts of the standard, the designation of the material types and the general requirements applicable to non-impregnated densified laminated wood for electrical purposes includes the definitions required for the understanding of all three parts of the standard, the designation of the material types and the general requirements applicable to non-impregnated densified laminated wood for electrical purposes. This specification is intended to cover only sheets and rings of nominal thicknesses between 6 mm and 100 mm, inclusive. The main changes from the previous edition are as follows: - addition of application use and safety statements; - redefinition of ring and sheet; - appropriate additions to the subclauses; - reformatting of text to bring it in line with the IEC document format.
IEC 61061-1:2006 includes the definitions required for the understanding of all three parts of the standard, the designation of the material types and the general requirements applicable to non-impregnated densified laminated wood for electrical purposes includes the definitions required for the understanding of all three parts of the standard, the designation of the material types and the general requirements applicable to non-impregnated densified laminated wood for electrical purposes. This specification is intended to cover only sheets and rings of nominal thicknesses between 6 mm and 100 mm, inclusive. The main changes from the previous edition are as follows: - addition of application use and safety statements; - redefinition of ring and sheet; - appropriate additions to the subclauses; - reformatting of text to bring it in line with the IEC document format.
IEC 61061-1:2006 is classified under the following ICS (International Classification for Standards) categories: 17.220.99 - Other standards related to electricity and magnetism; 29.035.01 - Insulating materials in general. The ICS classification helps identify the subject area and facilitates finding related standards.
IEC 61061-1:2006 has the following relationships with other standards: It is inter standard links to IEC 61061-1:1998. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
IEC 61061-1:2006 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
INTERNATIONAL IEC
STANDARD 61061-1
Third edition
2006-10
Non-impregnated densified laminated
wood for electrical purposes –
Part 1:
Definitions, designation and general requirements
Reference number
Publication numbering
As from 1 January 1997 all IEC publications are issued with a designation in the
60000 series. For example, IEC 34-1 is now referred to as IEC 60034-1.
Consolidated editions
The IEC is now publishing consolidated versions of its publications. For example,
edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the base publication, the
base publication incorporating amendment 1 and the base publication incorporating
amendments 1 and 2.
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by the technical committee which has prepared this publication, as well as the list
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INTERNATIONAL IEC
STANDARD 61061-1
Third edition
2006-10
Non-impregnated densified laminated
wood for electrical purposes –
Part 1:
Definitions, designation and general requirements
© IEC 2006 ⎯ Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
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Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
PRICE CODE
Commission Electrotechnique Internationale G
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue
– 2 – 61061-1 © IEC:2006(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
NON-IMPREGNATED DENSIFIED LAMINATED WOOD
FOR ELECTRICAL PURPOSES –
Part 1: Definitions, designation 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
misinterpretation by any end user.
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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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) 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 61061-1 has been prepared by IEC technical committee 15: Solid
electrical insulating materials.
This third edition cancels and replaces the second edition published in 1998, and constitutes a
technical revision. The main changes from the previous edition are as follows:
– addition of application use and safety statements;
– redefinition of ring and sheet;
– appropriate additions to the subclauses;
– reformatting of text to bring it in line with current IEC document format.
The text of this standard is based on the following documents:
FDIS Report on voting
15/343/FDIS 15/350/RVD
61061-1 © IEC:2006(E) – 3 –
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
A list of all parts of the IEC 61061 series, under the general title Non-impregnated densified
laminated wood for electrical purposes, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until the
maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.
– 4 – 61061-1 © IEC:2006(E)
NON-IMPREGNATED DENSIFIED LAMINATED WOOD
FOR ELECTRICAL PURPOSES –
Part 1: Definitions, designation and general requirements
1 Scope
This part of IEC 61061 includes the definitions required for the understanding of all three parts
of the standard, the designation of the material types and the general requir
...
IEC 61061-1 ®
Edition 3.0 2006-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Non-impregnated densified laminated wood for electrical purposes –
Part 1: Definitions, designation and general requirements
Stratifiés de bois densifié, non imprégnés, à usages électriques –
Partie 1: Définitions, désignation et exigences générales
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IEC 61061-1 ®
Edition 3.0 2006-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Non-impregnated densified laminated wood for electrical purposes –
Part 1: Definitions, designation and general requirements
Stratifiés de bois densifié, non imprégnés, à usages électriques –
Partie 1: Définitions, désignation et exigences générales
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
G
CODE PRIX
ICS 17.220.99; 29.035.01 ISBN 978-2-88910-403-1
– 2 – 61061-1 © IEC:2006
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
NON-IMPREGNATED DENSIFIED LAMINATED WOOD
FOR ELECTRICAL PURPOSES –
Part 1: Definitions, designation 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
misinterpretation by any end user.
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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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) 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 61061-1 has been prepared by IEC technical committee 15: Solid
electrical insulating materials.
This third edition cancels and replaces the second edition published in 1998, and constitutes a
technical revision. The main changes from the previous edition are as follows:
– addition of application use and safety statements;
– redefinition of ring and sheet;
– appropriate additions to the subclauses;
– reformatting of text to bring it in line with current IEC document format.
61061-1 © IEC:2006 – 3 –
This bilingual version, published in 2009-09, corresponds to the English version.
The text of this standard is based on the following documents:
FDIS Report on voting
15/343/FDIS 15/350/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
The French version of this standard has not been voted upon.
A list of all parts of the IEC 61061 series, under the general title Non-impregnated densified
laminated wood for electrical purposes, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until the
maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
– 4 – 61061-1 © IEC:2006
NON-IMPREGNATED DENSIFIED LAMINATED WOOD
FOR ELECTRICAL PURPOSES –
Part 1: Definitions, designation and general requirements
1 Scope
This part of IEC 61061 includes the definitions required for the understanding of all three parts
of the standard, the designation of the material types and the general requirements applicable
to non-impregnated densified laminated wood for electrical purposes.
This specification is intended to cover only sheets and rings of nominal thicknesses between
6 mm and 100 mm, inclusive.
Materials which conform to this specification meet established levels of performance. However,
the selection of a material by a user for a specific application should be based on the actual
requirements necessary for adequate performance in that application and not based on this
specification alone.
Safety warning: It is the responsibility of the user of the methods contained or referred to in this
document to ensure that they are used in a safe manner.
2 Normative references
The following referenced documents are indispensable for the application 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 60296, Fluids for electrotechnical applications – Unused mineral insulating oils for
transformers and switchgear
IEC 61061-2, Non-impregnated, densified laminated wood for electrical purposes – Part 2:
Methods of test
IEC 61061-3 (all sheets), Non-impregnated, densified laminated wood for electrical purposes –
Part 3: Specifications for individual materials
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply:
3.1
veneer
single non-laminated ply with a thickness of not more than 2,5 mm in the non-pressed
condition, for example produced from beech (fagus silvatica), North-American maple (acer
saccherem) or birch (betula pendula)
3.2
non-impregnated densified laminated wood
laminated wood made from layers of wood veneer bonded together under controlled conditions
of heat and pressure using a thermosetting synthetic resin adhesive
61061-1 © IEC:2006 – 5 –
3.3
sheet
material with parallel or crosswise arrangement of veneers
3.4
direction A and direction B
two directions in the plane of laminations, mutually at right angles, one of which is parallel with
an edge of the sheet
3.5
ring
ring form manufactured either by
a) cutting out the ring from a sheet made with crosswise arrangement of veneers (positioned
at 90° to one another);
b) pressing substantially tangentially arranged veneers laid up in a circular form; or
c) pressing veneers assembled in a circular form, with each layer arranged at 45° to the layer
preceding it
NOTE Because of the different methods of manufacture which may be used, the three types clearly differ in their
properties and therefore the required type of ring should be specified in the purchase contract.
4 Designation
4.1 General
The types of material covered by this specification shall be designated by:
– the shape of the material: sheet or ring;
– the number of the IEC standard: IEC 61061;
– a letter to denote the arrangement of the veneers according to 4.2;
– a digit to denote the range of densities according to 4.3;
– a letter to denote the kind of wood according to 4.4;
– the dimensions of the
• sheet: thickness in millimetres × width in millimetres × length in millimetres;
• ring: thickness in millimetres × radial ring width in millimetres × outer diameter in
millimetres.
4.2 Arrangements of veneers
The arrangement of veneers shall be denoted by the following letters:
P: parallel arrangement;
C: crosswise arrangement;
T: tangential arrangement;
A: veneers arranged at 45° to the preceding layer.
NOTE In arrangements P and T, for manufacturing reasons, up to 20 % of the veneers may be arranged in such a
manner that the fibres are perpendicular to the fibres of the rest of the veneers. When arranging the layers
crosswise, it is permissible to have two veneers on top of each other in the same direction, in order to compensate
for the variation in mass of each ply of veneer.
4.3 Apparent density in grams per cubic centimetre (g/cm )
The apparent density shall be denoted by the following digits:
– 6 – 61061-1 © IEC:2006
1: apparent density ≥ 0,7 < 0,9 g/cm ;
2: apparent density ≥ 0,9 < 1,1 g/cm ;
3: apparent density ≥ 1,1 < 1,2 g/cm ;
4: apparent density ≥ 1,2 < 1,3 g/cm .
4.4 Kind of wood
The kind of wood shall be denoted by the following letters:
B: birch;
M: maple;
R: beech.
4.5 Examples of complete IEC designations
Sheet of non-impregnated, densified, laminated wood with crosswise arrangement of veneers
3 3
of beech, with an apparent density greater than or equal to 1,1 g/cm but less than 1,2 g/cm ,
with a thickness of 10 mm, a width of 1 000 mm and a length of 2 000 mm:
Sheet IEC 61061 – C3R – 10 × 1 000 × 2 000
Ring of non-impregnated, densified, laminated wood with tangential arrangement of veneers of
3 3
beech, with an apparent density greater than or equal to 0,9 g/cm but less than 1,1 g/cm ,
with a thickness of 80 mm, a radial ring width of 100 mm and an outer diameter of 1 500 mm:
Ring IEC 61061 – T2R – 80 × 100 × 1 500
5 General requirements
5.1 Composition
The material shall be produced from wood veneer layers and thermosetting resin. All materials,
i.e. the wood veneers and the resin, shall be resistant to transformer oils according to
IEC 60296 and shall not have any detrimental effect on them, according to the test method in
IEC 61061-2.
5.2 Defects – all types
No diseased areas or electrically conducting inclusions are permitted, but natural staining due
to causes other than fungus attack may be accepted. For sheets, the direction of the fibres
shall not deviate by more than 5° ± 1° from being parallel to the edge of the sheet.
5.3 Finish
5.3.1 Sheets
Sheets shall be plane, smooth and free from local deformations. All joints between veneers
shall be reasonably close-butted and substantially free from gaps and overlaps. Sheets shall be
supplied with trimmed edges, unless otherwise agreed upon between the customer and the
manufacturer.
NOTE With some veneers, it is not possible to be totally free of voids, gaps and overlap
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