IEC 60836:2015

IEC 60836 ®
Edition 3.0 2015-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Specifications for unused silicone insulating liquids for electrotechnical
purposes
Spécifications pour liquides isolants silicones neufs pour usages
électrotechniques
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IEC 60836 ®
Edition 3.0 2015-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Specifications for unused silicone insulating liquids for electrotechnical

purposes
Spécifications pour liquides isolants silicones neufs pour usages

électrotechniques
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.040.10 ISBN 978-2-8322-2789-3

– 2 – IEC 60836:2015 © IEC 2015
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Properties . 6
4.1 General properties . 6
4.2 Properties relating to health, safety and environment (HSE) . 7
4.2.1 Handling . 7
4.2.2 Disposal . 7
5 General delivery requirements and identification. 7
6 Storage and maintenance . 7
7 Sampling . 7
8 Properties and test methods . 8
8.1 Colour and appearance . 8
8.1.1 Colour . 8
8.1.2 Appearance . 8
8.2 Density . 8
8.3 Kinematic viscosity . 8
8.4 Flash point . 8
8.5 Fire point . 8
8.6 Refractive index . 8
8.7 Pour-point . 8
8.8 Water content . 8
8.9 Acidity . 8
8.10 Breakdown voltage . 8
8.11 Dielectric dissipation factor, permittivity, d.c. resistivity . 8
8.12 Gassing under electrical stress and ionization . 8
8.13 Flammability . 9
9 Individual specifications . 9
9.1 General . 9
9.2 Silicone transformer liquid . 9
9.3 Other silicone liquids for electrotechnical purposes . 10
Bibliography . 11

Table 1 – Specification of silicone transformer liquid . 9
Table 2 – Minimum requirements for silicone liquids . 10

IEC 60836 © IEC 2015 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SPECIFICATIONS FOR UNUSED SILICONE INSULATING
LIQUIDS FOR ELECTROTECHNICAL PURPOSES

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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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
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between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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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.
The International Standard IEC 60836 has been prepared by IEC technical committee 10:
Fluids for electrotechnical applications.
This third edition cancels and replaces the second edition published in 2005. This edition
constitutes a technical revision.
This edition includes the following major technical changes with regard to the second edition:
a) classification of liquids according to IEC 61039 have been adapted with respect to the
latest edition of IEC 61039:2008;
b) classification of liquids according to IEC 61100:1992 have been removed as IEC 61100
has been withdrawn;
c) minimum requirements for other silicone liquids for electrotechnical purposes have been
added.
– 4 – IEC 60836:2015 © IEC 2015
The text of this standard is based on the following documents:
FDIS Report on voting
10/961FDIS 10/968/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.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC website 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.
IEC 60836 © IEC 2015 – 5 –
SPECIFICATIONS FOR UNUSED SILICONE INSULATING
LIQUIDS FOR ELECTROTECHNICAL PURPOSES

1 Scope
This International Standard covers specifications and test methods for unused silicone liquids
intended for use in transformers and other electrotechnical equipment.
The specified characteristics of silicone transformer liquid classified as L-NTUK-8360300 (in
accordance with IEC 61039) are described in Table 1.
Besides the standard transformer applications there are other applications of silicone liquids,
such like cable accessories, capacitors, electrical magnets etc. The specified characteristics
and minimum requirements for these liquids are described in Table 2.
NOTE Maintenance of used silicone liquid in electrotechnical equipment is covered in a separate publication
IEC 60944.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60156:1995, Insulating liquids – Determination of the breakdown voltage at power
frequency – Test method
IEC 60247, Insulating liquids – Measurement of relative permittivity, dielectric dissipation
factor (tan δ) and d.c. resistivity
IEC 60296, Fluids for electrotechnical applications – Unused mineral insulating oils for
transformers and switchgear
IEC 60475, Method of sampling insulating liquids
IEC 60628, Gassing of insulating liquids under electrical stress and ionization
IEC 60814, Insulating liquids – Oil-impregnated paper and pressboard – Determination of
water by automatic coulometric Karl Fischer titration
IEC 60944, Guide for the maintenance of silicone transformer liquids
IEC 61039:2008, Classification of insulating liquids
IEC 62021-3, Insulating liquids – Determination of acidity – Part 3: Test methods for non-
mineral insulating oils
ISO 2211, Liquid chemical products – Measurement of colour in Hazen units (platinum-cobalt
scale)
ISO 2592, Determination of flash and fire points – Cleveland open cup method

– 6 – IEC 60836:2015 © IEC 2015
ISO 2719, Determination of flash point – Pensky Martens closed cup method
ISO 3016, Petroleum products – Determination of pour point
ISO 3104, Petroleum products – Transparent and opaque liquids – Determination of kinematic
viscosity and calculation of dynamic viscosity
ISO 3675, Crude petroleum and liquid petroleum products – Laboratory determination of
density – Hydrometer method
ISO 5661, Petroleum products – Hydrocarbon liquids – Determination of refractive index
ISO 12185, Crude petroleum and petroleum products – Determination of density – Oscillating
U-tube method
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
silicone insulating liquids
liquid organopolysiloxanes whose molecular structure consists mainly of linear chains of
alternating silicon and oxygen atoms, with hydrocarbon groups attached to the silicon atoms
3.2
silicone transformer liquid
polydimethyl siloxane, without additives, primarily for use in transformers
Note 1 to entry: According to IEC 61039, this type is classified as L-NTUK-8360300.
3.3
other silicone liquids for electrotechnical purposes
polydimethyl siloxane, without additives, applied for electrotechnical purposes
Note 1 to entry: Classification of other fluids for electrotechnical purposes according to IEC 61039 shall be made
in relation to their main application and their fire point, e.g. a liquid for capacitors with a fire point of less than
300 °C is classified as L-NCUO-8360300.
4 Properties
4.1 General properties
As defined in 3.2, silicone liquid for transformers has high flash and fire points and is
therefore difficult to ignite. If combustion occurs, heat release rate is much lower than that of
hydrocarbon oils.
In addition to use at similar working temperatures to those of transformers containing mineral
transformer oil, silicone insulating liquids may also be used in appropriately designed
electrotechnical equipment operating at higher temperatures.
The solubility of water in silicone liquids is greater than in mineral oils. Other physical
characteristics which are important for the design of electrotechnical equipment, e.g. heat
transfer, may also be different from those of mineral transformer oil and will need to be taken
fully into account by the designer.

IEC 60836 © IEC 2015 – 7 –
4.2 Properties relating to health, safety and environment (HSE)
4.2.1 Handling
Silicone liquids ultimately degrade in nature to simple, naturally occurring substances. Their
handling is not hazardous to health.
Direct contact with the eyes may cause slight irritation. Safety glasses should be worn to
avoid splashing the eyes. In the case of eye contact, irrigation with large quantities of clean
running water should relieve any irritation. If irritation persists, seek medical advice.
Detailed information on safe handling of these liquids can be obtained from manufacturers or
suppliers.
4.2.2 Disposal
Local regulations shall be complied with. The preferred means of disposal is recycling by a
qualified contractor. Waste liquid may be incinerated. Spillages should be cleaned using
adsorbent media. Small quantities of liquid entering the environment present no special
hazard.
5 General delivery requirements and identification
Transport of silicone insulating liquid shall be in clean hermetically sealed containers whose
lining does not interact with the contents.
Each container shall display the following information:
– number of this standard;
– supplier’s designation;
– batch number;
– any notices required by local regulatory authorities.
Electrotechnical equipment filled with silicone insulating liquid should be labelled for
identification with respect to the insulation used.
6 Storage and maintenance
Storage should preferably be indoors and shall be in sealed containers to prevent ingress of
moisture and dirt. If accidentally contaminated by water and/or solid particles during storage,
the liquid can usually be restored to acceptable quality by the procedures described in
IEC 60944.
7 Sampling
The liquid shall be sampled in accordance with IEC 60475, using the procedure consistent
with the density of the liquid being sampled. Isopropyl alcohol is suitable for cleaning the
sampling equipment.
– 8 – IEC 60836:2015 © IEC 2015
8 Properties and test methods
8.1 Colour and appearance
8.1.1 Colour
This property shall be measured according to ISO 2211.
8.1.2 Appearance
This property shall be evaluated by examining a representative sample of approximately
100 mm in thickness, in transmitted light and at ambient temperature.
8.2 Density
This property shall be measured at 20 °C according to ISO 3675 but measurement according
to ISO 12185 is accepted as well.
8.3 Kinematic viscosity
This property shall be measured at 40 °C according to ISO 3104.
8.4 Flash point
This property shall be measured according to ISO 2719.
8.5 Fire point
This property shall be measured according to ISO 2592.
8.6 Refractive index
This property shall be measured according to ISO 5661.
8.7 Pour-point
This property shall be measured according to ISO 3016.
8.8 Water content
This property shall be measured according to IEC 60814.
8.9 Acidity
This property shall be measured according to IEC 62021-3.
8.10 Breakdown voltage
This property shall be measured according to IEC 60156 and with particular attention to
IEC 60156:1995, 3.4.2.
8.11 Dielectric dissipation factor, permittivity, d.c. resistivity
These properties shall be determined at 90 °C by the methods described in IEC 60247.
Isopropyl alcohol or acetone are suitable for cleaning the test cell.
8.12 Gassing under electrical stress and ionization
This property shall be measured according to IEC 60628.

IEC 60836 © IEC 2015 – 9 –
8.13 Flammability
Fire hazard measurement of insulating liquids is now studied by IEC technical committee 89.
9 Individual specifications
9.1 General
The specifications given in Table 1 and Table 2 applies only to unused silicone liquids
intended for use in electrotechnical equipment, as received from the supplier and before any
treatment or introduction into electrotechnical equipment. The liquid sampled in accordance
with Clause 7 shall be tested in accordance with the appropriate test methods given in
Clause 8. The characteristics of the liquid when tested shall comply with the requirements
given in Table 1 and Table 2.
9.2 Silicone transformer liquid
This liquid is polydimethyl siloxane without additives, primarily for use in transformers.
According to IEC 61039, it is classified as L-NTUK-8360300.
When tested in accordance with the methods specified in Clause 8, the properties of silicone
transformer liquid shall meet the requirements given in Table 1.
Table 1 – Specification of silicone transformer liquid
Property Test method Permissible values Notes
(clause or
subclause)
Colour 8.1.1 Max.35
Appearance 8.1.2 Clear, free from suspended
matter and sediment
Density at 20 °C (kg/dm ) 8.2 0,955 to 0,970
Kinematic viscosity at 40 °C (mm /s) 8.3
40 ± 4
Flash point (°C) 8.4 Min. 240
Fire point (°C) 8.5 Min. 340
Refractive index at 20 °C 8.6 1,404 ± 0,002
Pour point (°C) 8.7 Max. –50
Water content (mg/kg) 8.8 Max. 50 see
NOTE
Acidity (mg KOH/g) 8.9 Max. 0,01 see
NOTE
Breakdown voltage (kV) 8.10 Min. 40 see
NOTE
Dielectric dissipation factor (DDF) at 90 °C and 50 Hz 8.11 Max. 0,001 see
NOTE
Permittivity at 90 °C 8.11 see
2,55 ± 0,05
NOTE
8.11 Min. 100 see
DC resistivity at 90 °C (GΩ × m)
NOTE
NOTE For untreated liquid, as received.

– 10 – IEC 60836:2015 © IEC 2015
9.3 Other silicone liquids for electrotechnical purpos
...