IEC 60112:2003+AMD1:2009 CSV

Method for the determination of the proof and the comparative tracking indices of solid insulating materials

IEC 60112:2003+A1:2009 Specifies the method of test for the determination of the proof and comparative tracking indices of solidinsulating materials on pieces taken from parts of equipment and on plaques of material using alternating voltages. The standard provides for the determination of erosion when required. Test results cannot be used directly for the evaluation of safe creepage distances when designing electrical apparatus. Has the status of a basic safety publication in accordance with IEC Guide 104. Major changes since the previous edition are the following: The selection of a material for a specific application frequently involves compromises in the levels of the individual properties and test criteria. In the previous edition of IEC 60112 the test criteria required "no burning of the specimen", but this gave rise to two issues:
- difficulties in the identification of burning which includes all types of combustion, e.g. flaming, and smouldering in the situation where scintillations had occurred giving rise in many cases to carbon on the surface of the specimen, and
- a situation in which some product committees had found it necessary to dispense with the "no burning" criterion in the tracking tests which they replaced by flame tests on the final product, thereby giving rise to two types of CTI/PTI with different criteria.
The contents of the corrigenda of June 2003 and October 2003 have been included in this copy. This consolidated version consists of the fourth edition (2003) and its amendment 1 (2009). Therefore, no need to order amendment in addition to this publication.

Méthode de détermination des indices de résistance et de tenue au cheminement des matériaux isolants solides

La CEI 60112:2003+A1:2009 Spécifie la méthode d'essai pour déterminer les indices de résistance et de tenue au cheminement des matériaux isolants solides sur des échantillons prélevés sur des parties d'équipement et des plaques de matériau en utilisant des tensions alternatives. Cette norme détermine la valeur de l'érosion quand cela est demandé. Les résultats d'essai ne peuvent pas être utilisés directement tels quels pour évaluer les lignes de fuite de sécurité lors de la conception des appareils électriques. A le statut de publication fondamentale de sécurité, conformément au Guide CEI 104. Les modifications majeures par rapport à l'édition précédente sont celles qui suivent: Le choix d'un matériau pour une application spécifique implique fréquemment des compromis au niveau des propriétés individuelles et des critères d'essai. Dans la précédente édition de la CEI 60112, les critères d'essai requéraient «aucun brûlage de l'éprouvette» mais cela a induit deux problèmes:
- des difficultés pour différencier le brûlage qui comprend tous les types de combustion, par exemple flammes, et la combustion lente dans une situation où des étincelages se produisent, entraînant une carbonisation à la surface de l'éprouvette, et
- une situation dans laquelle certains comités de produit ont trouvé nécessaire de se dispenser du critère «aucun brûlage», pour les essais de cheminement, critère qu'ils ont remplacé par les essais de flamme sur le produit final, faisant ainsi apparaître deux types de IRC/ITC avec des critères différents. Le contenu des corrigenda de juin 2003 et octobre 2003 a été pris en considération dans cet exemplaire.  Cette version consolidée comprend la quatrième édition (2003) et son amendement 1 (2009). Il n'est donc pas nécessaire de commander l'amendement avec cette publication.

General Information

• Status: Published
• Publication Date: 12-Oct-2009
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 19.080 - Electrical and electronic testing
• ICS: 29.035.01 - Insulating materials in general
• Technical Committee: TC 112 - Evaluation and qualification of electrical insulating materials and systems
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 28-Oct-2020

Standards Content (Sample)

IEC 60112
®
Edition 4.1 2009-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ
Method for the determination of the proof and the comparative tracking indices
of solid insulating materials

Méthode de détermination des indices de résistance et de tenue au
cheminement des matériaux isolants solides
IEC 60112:2003+A1:2009

---------------------- Page: 1 ----------------------
THIS PUBLICATION IS COPYRIGHT PROTECTED
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IEC 60112
®
Edition 4.1 2009-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
BASIC SAFETY PUBLICATION
PUBLICATION FONDAMENTALE DE SÉCURITÉ
Method for the determination of the proof and the comparative tracking indices
of solid insulating materials

Méthode de détermination des indices de résistance et de tenue au
cheminement des matériaux isolants solides

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CF
CODE PRIX
ICS 19.080; 29.035.01 ISBN 978-2-88910-059-0
® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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– 2 – 60112 © IEC:2003+A1:2009
CONTENTS
FOREWORD. 3

1 Scope. 5
2 Normative references. 5
3 Terms and definitions. 6
4 Principle. 7
5 Test specimen. 7
6 Test specimen conditioning. 8
6.1 Environmental conditioning. 8
6.2 Test specimen surface state. 8
7 Test apparatus. 8
7.1 Electrodes. 8
7.2 Test circuit. 9
7.3 Test solutions. 9
7.4 Dropping device. 9
7.5 Test specimen support platform.10
7.6 Electrode assembly installation.10
8 Basic test procedure.10
8.1 General.10
8.2 Preparation.10
8.3 Test procedure.11
9 Determination of erosion.11
10 Determination of proof tracking index (PTI) .11
10.1 Procedure.11
10.2 Report.12
11 Determination of comparative tracking index (CTI) .12
11.1 General.12
11.2 Determination of the 100 drop point.12
11.3 Determination of the maximum 50 drop withstand voltage .13
11.4 Report.14

Annex A (informative) List of factors that should be considered by product committees .18
Annex B (informative) Electrode material selection .19

Bibliography.20

Figure 1 – Electrode .16
Figure 2 – Electrode / specimen arrangement .16
Figure 3 – Example of typical electrode mounting and specimen support .17
Figure 4 – Example of test circuit.17

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60112 © IEC:2003+A1:2009 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

METHOD FOR THE DETERMINATION OF THE PROOF
AND THE COMPARATIVE TRACKING INDICES
OF SOLID INSULATING MATERIALS



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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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 60112 has been prepared by subcommittee 15E: Methods of test,
of IEC technical committee 15: Insulating materials.
This consolidated version of IEC 60112 consists of the fourth edition (2003) [documents
15E/209/FDIS and 15E/213/RVD], its amendment 1 (2009) [documents 112/116/CDV and
112/130/RVC] and its corrigenda of June 2003 and October 2003.
The technical content is therefore identical to the base edition and its amendment and has
been prepared for user convenience.
It bears the edition number 4.1.
A vertical line in the margin shows where the base publication has been modified by
amendment 1.

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– 4 – 60112 © IEC:2003+A1:2009
Major changes since the previous edition are the following:
The selection of a material for a specific application frequently involves compromises in the
levels of the individual properties and test criteria. In the previous edition of IEC 60112 the
test criteria required "no burning of the specimen", but this gave rise to two issues:
– difficulties in the identification of burning which includes all types of combustion, e.g.
flaming, and smouldering in the situation where scintillations had occurred giving rise in
many cases to carbon on the surface of the specimen, and
– a situation in which some product committees had found it necessary to dispense with the
"no burning" criterion in the tracking tests which they replaced by flame tests on the final
product, thereby giving rise to two types of CTI/PTI with different criteria.
This standard attempts to regularize this situation.
It has the status of a basic safety publication in accordance with IEC Guide 104.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of the base publication and its amendments 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.

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60112 © IEC:2003+A1:2009 – 5 –
METHOD FOR THE DETERMINATION OF THE PROOF
AND THE COMPARATIVE TRACKING INDICES
OF SOLID INSULATING MATERIALS



1 Scope
This International standard specifies the method of test for the determination of the proof and
comparative tracking indices of solid insulating materials on pieces taken from parts of
equipment and on plaques of material using alternating voltages.
The standard provides for the determination of erosion when required.
NOTE 1 The proof tracking index is used as an acceptance criterion as well as a means for the quality control of
materials and fabricated parts. The comparative tracking index is mainly used for the basic characterization and
comparison of the properties of materials.
Test results cannot be used directly for the evaluation of safe creepage distances when
designing electrical apparatus.
NOTE 2 This test discriminates between materials with relatively poor resistance to tracking, and those with
moderate or good resistance, for use in equipment which can be used under moist conditions. More severe tests,
of longer duration are required for the assessment of performance of materials for outdoor use, utilizing higher
voltages and larger test specimens (see the inclined plane test of IEC 60587). Other test methods such as the
inclined method may rank materials in a different order from the drop test given in this standard.
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 Guide 104:1997, The preparation of safety publications and the use of basic safety
publications and group safety publications
ISO 293:1986, Plastics – Compression moulding test specimens of thermoplastic materials
ISO 294-1:1996, Plastics – Injection moulding of test specimens of thermoplastic materials –
Part 1: General principles, and moulding of multi-purpose and bar test specimens
ISO 294-3:2002, Plastics – Injection moulding of test specimens of thermoplastic materials –
Part 3: Small plates
ISO 295:1991, Plastics – Compression moulding of test specimens of thermosetting materials

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– 6 – 60112 © IEC:2003+A1:2009
3 Terms and definitions
For the purposes of this International Standard, the following definitions apply:
3.1
tracking
progressive formation of conducting paths, which are produced on the surface and/or within
a solid insulating material, due to the combined effects of electric stress and electrolytic
contamination
3.2
tracking failure
failure of insulation due to tracking between conducting parts
NOTE In the present test, tracking is indicated by operation of an over-current device due to the passage of
a current of at least 0,5 A for at least 2 s across the test surface and/or within the specimen.
3.3
electrical erosion
wearing away of insulating material by the action of electrical discharges
3.4
air arc
arc between the electrodes above the surface of the specimen
3.5
comparative tracking index
CTI
numerical value of the maximum voltage at which five test specimens withstand the test
period for 50 drops without tracking failure and without a persistent flame occurring and
including also a statement relating to the behaviour of the material when tested using
100 drops (see 11.4)
NOTE 1 The criteria for CTI may also require a statement concerning the degree of erosion.
NOTE 2 Although a non-persistent flame is allowed in the test without constituting failure, materials which
generate no flame at all are preferred unless other factors are considered to be more important. See also Annex A.
3.6
persistent flame
in case of dispute – one which burns for more than 2 s
3.7
proof tracking index
PTI
numerical value of the proof voltage in volts at which five test specimens withstand the test
period for 50 drops without tracking failure and without a persistent flame occurring
NOTE Although a non-persistent flame is allowed in the test without constituting failure, materials which generate
no flame at all are preferred unless other factors are considered to be more important. See also Annex A.

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60112 © IEC:2003+A1:2009 – 7 –
4 Principle
The upper surface of the test specimen is supported in an approximately horizontal plane and
subjected to an electrical stress via two electrodes. The surface between the electrodes is
subjected to a succession of drops of electrolyte either until the over-current device operates,
or until a persistent flame occurs, or until the test period has elapsed.
The individual tests are of short duration (less than 1 h) with up to 50 or 100 drops of about
20 mg of electrolyte falling at 30 s intervals between platinum electrodes, 4 mm apart on the
test specimen surface.
An a.c. voltage between 100 V and 600 V is applied to the electrodes during the test.
During the test, specimens may also erode or soften, thereby allowing the electrodes to
penetrate them. The formation of a hole through the test specimen during a test is to be
reported together with the hole depth (test specimen thickness). Retests may be made using
thicker test specimens, up to a maximum of 10 mm.
NOTE The number of drops needed to cause failure by tracking usually increases with decreasing applied voltage
and, below a critical value, tracking ceases to occur.
5 Test specimen
Any approximately flat surface may be used, provided that the area is sufficient to ensure that
during the test no liquid flows over the edges of the test specimen.
NOTE 1 Flat surfaces of not less than 20 mm × 20 mm are recommended to reduce the probability of electrolyte
loss over the specimen edge although smaller sizes may be used, subject to no electrolyte loss, e.g. ISO 3167,
15 mm × 15 mm multi-purpose test specimens.
NOTE 2 It is preferable to use separate test specimens for each test. If several tests are to be made on the same
test piece, care should be taken to ensure that the testing points are sufficiently far from each other so that
splashes or fumes from the testing point will not contaminate the other areas to be tested.
The thickness of the test specimen shall be 3 mm or more. Individual pieces of material may
be stacked to obtain the required thickness of at least 3 mm.
NOTE 3 The values of the CTI obtained on specimens with a thickness below 3 mm may not be comparable with
those obtained on thicker specimens because of greater heat transmission to the glass support through thinner test
specimens. For this reason, stacked specimens are allowed.
Test specimens shall have nominally smooth and untextured surfaces which are free from
surface imperfections such as scratches, blemishes, impurities, etc, unless otherwise stated
in the product standard. If this is impossible, the results shall be reported together with a
statement describing the surface of the specimen because certain characteristics on the
surface of the specimen could add to the dispersion of the results.
For tests on parts of products, where it is impossible to cut a suitable test specimen from a
part of a product, specimens cut from moulded plaques of the same insulating material may
be used. In these cases care should be taken to ensure that both the part and the plaque are
produced by the same fabrication process wherever possible. Where the details of the final
fabrication process are unknown, methods given in ISO 293, ISO 294-1 and ISO 294-3 and
ISO 295 may be appropriate.
NOTE 4 The use of different fabrication conditions/processes may lead to different levels of performance in
the PTI and CTI test.
NOTE 5 Parts moulded using different flow directions may also exhibit different levels of performance in the PTI
and CTI test.
In special cases, the test specimen may be ground to obtain a flat surface.

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– 8 – 60112 © IEC:2003+A1:2009
Where the direction of the electrodes relative to any feature of the material is significant,
measurements shall be made in the direction of the feature and orthogonal to it. The direction
giving the lower CTI shall be reported, unless otherwise specified.
6 Test specimen conditioning
6.1 Environmental conditioning
Unless otherwise specified, the test specimens shall be conditioned for a minimum of 24 h at
23 °C ± 5 K, with (50 ± 10) % RH.
6.2 Test specimen surface state
Unless otherwise specified,
a) tests shall be made on clean surfaces;
b) any cleaning procedure used shall be reported. Wherever possible, the details shall be
agreed between supplier and customer.
NOTE Dust, dirt, fingerprints, grease, oil, mould release or other contaminants may influence the results. Care
should be taken when cleaning the test specimen to avoid swelling, softening, abrasion or other damage to the
material.
7 Test apparatus
7.1 Electrodes
Two electrodes of platinum with a minimum purity of 99 % shall be used (see Annex B). The
two electrodes shall have a rectangular cross-section of (5 ± 0,1) mm × (2 ± 0,1) mm, with
one end chisel-edged with an angle of 30° ± 2° (see Figure 1). The sharp edge shall be
removed to produce an approximately flat surface, 0,01 mm to 0,1 mm wide.
NOTE 1 A microscope with a calibrated eyepiece has been found suitable for checking the size of the end
surface.
NOTE 2 It is recommended that mechanical means are used to re-furbish the electrode shape after a test to
ensure that the electrodes maintain the required tolerances, especially with respect to the edges and corners.
At the start of the test, the electrodes shall be symmetrically arranged in a vertical plane, the
total angle between them being 60° ± 5° and with opposing electrode faces approximately
vertical on a flat horizontal surface of the test specimen (see Figure 2 ). Their separation
along the surface of the test specimen at the start of the test shall be 4,0 mm ± 0,1 mm.
A thin metal rectangular slip gauge shall be used to check the electrode separation. The
electrodes shall move freely and the force exerted by each electrode on the surface of the
test specimen at the start of the test shall be 1,00 N ± 0,05 N. The design shall be such that
the force can be expected to remain at the initial level during the test.
One typical type of arrangement for applying the electrodes to the test specimen is shown in
Figure 3. The force shall be verified at appropriate intervals.
Where tests are made solely on those materials where the degree of electrode penetration is
small, the electrode force may be generated by the use of springs. However, gravity should be
used to generate the force on general purpose equipment (see Figure 3).
NOTE 3 With most, but not all designs of apparatus, if the electrodes move during a test due to softening or
erosion of the specimen, their tips will prescribe an arc and the electrode gap will change. The magnitude and
direction of the gap change will depend on the relative positions of the electrode pivots and the electrode/specimen
contact points. The significance of these changes will probably be material dependent and has not been
determined. Differences in design could give rise to differences in inter-apparatus results.

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60112 © IEC:2003+A1:2009 – 9 –
7.2 Test circuit
The electrodes shall be supplied with a substantially sinusoidal voltage, variable between
100 V and 600 V at a frequency of 48 Hz to 62 Hz. The voltage measuring device shall
indicate a true r.m.s. value and shall have a maximum error of 1,5 %. The power of the source
shall be not less than 0,6 kVA. An example of a suitable test circuit is shown in Figure 4.
A variable resistor shall be capable of adjusting the current between the short-circuited
electrodes to (1,0 ± 0,1) A and the voltage indicated by the voltmeter shall not decrease by
more than 10 % when this current flows (see Figure 4). The instrument used to measure the
value of the short-circuit current shall have a maximum error of ±3 %.
The input supply voltage to the apparatus shall be adequately stable.
The over-current device shall operate when a current with an r.m.s. value of 0,50 A with
a relative tolerance of ±10 %, has persisted for 2,00 s with a relative tolerance of ±10 %.
7.3 Test solutions
Solution A:
Dissolve approximately 0,1 % by mass of analytical reagent grade anhydrous ammonium
chloride (NH Cl), of a purity of not less than 99,8 %, in de-ionized water, having a conductivity
4
of not greater than 1 mS/m to give a resistivity of (3,95 ± 0,05) Ωm at (23 ± 1) °C.
NOTE 1 Select the quantity of ammonium chloride to give a solution in the required range of resistivity.
Solution B:
Dissolve approximately 0,1 % by mass of analytical reagent grade anhydrous ammonium
chloride, of a purity of not less than 99,8 %, and 0,5 % ± 0,002 % by mass of sodium-di-butyl
naphthalene sulfonate in de-ionized water, having a conductivity of not greater than 1 mS/m,
to give a resistivity of (1,98 ± 0,05) Ωm at (23 ± 1) °C.
NOTE 2 Select the quantity of ammonium chloride to give a solution in the required range of resistivity.
Solution A is normally used, but where a more aggressive contaminant is required, Solution B
is recommended. To indicate that Solution B was used, the CTI or PTI value shall be followed
by the letter "M".

7.4 Dropping device
Drops of the test solution shall fall on to the specimen surface at intervals of 30 s ± 5 s. The
drops shall fall more or less centrally between the electrodes from a height of 35 mm ± 5 mm.
The time for 50 drops to fall on to the specimen shall be (24,5 ± 2) min.
The mass of a sequence of 50 drops shall lie between 0,997 g and 1,147 g. The mass of a
sequence of 20 drops shall lie between 0,380 g and 0,480 g.
NOTE 1 The mass of the drops may be determined by weighing with the appropriate laborato
...