IEC 60433:2021

IEC 60433 ®
Edition 4.0 2021-01
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Insulators for overhead lines with a nominal voltage above 1 000 V – Ceramic
insulators for AC systems – Characteristics of insulator units of the long rod
type
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IEC 60433 ®
Edition 4.0 2021-01
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Insulators for overhead lines with a nominal voltage above 1 000 V – Ceramic

insulators for AC systems – Characteristics of insulator units of the long rod

type
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.080.10; 29.240.20 ISBN 978-2-8322-9280-8

– 2 – IEC 60433:2021 RLV © IEC 2021
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Characteristics, dimensions and type of long rod insulators . 6
5 Designation and marking . 7
Bibliography . 11

Figure 1 – Long rod insulator with clevis couplings, type C . 10
Figure 2 – Long rod insulator with socket couplings, type B . 10

Table 1 – Specified values for long rod insulators . 8

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INSULATORS FOR OVERHEAD LINES
WITH A NOMINAL VOLTAGE ABOVE 1 000 V –
CERAMIC INSULATORS FOR AC SYSTEMS –
CHARACTERISTICS OF INSULATOR UNITS OF THE LONG ROD TYPE

FOREWORD
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This redline version of the official IEC Standard allows the user to identify the changes
made to the previous edition IEC 60433:1998. A vertical bar appears in the margin
wherever a change has been made. Additions are in green text, deletions are in
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– 4 – IEC 60433:2021 RLV © IEC 2021
International Standard IEC 60433 has been prepared by IEC technical committee 36:
Insulators.
This fourth edition cancels and replaces the third edition published in 1998. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) wording in Scope changed from "should" to "are intended to";
b) new normative references added;
c) title of Clause 4 amended, new Note 4 added;
d) Table 1 expanded to include more specified mechanical failing loads.
The text of this International Standard is based on the following documents:
FDIS Report on voting
36/498/FDIS 36/500/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://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.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
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colour printer.
INSULATORS FOR OVERHEAD LINES
WITH A NOMINAL VOLTAGE ABOVE 1 000 V –
CERAMIC INSULATORS FOR AC SYSTEMS –
CHARACTERISTICS OF INSULATOR UNITS OF THE LONG ROD TYPE

1 Scope
This International Standard is applicable to string insulator units of the long rod type with
insulating parts of ceramic material intended for use in AC overhead power lines with a
nominal voltage greater than 1 000 V and a frequency not greater than 100 Hz. It is also
applicable to insulators of similar design, used in substations.
This document is applicable to ceramic string insulator units of the long rod type, either with a
clevis end fitting at both ends for coupling with a tongue, or with a socket end fitting at both
ends for coupling with a pin ball.
The object of this document is to prescribe specified values for electrical and mechanical
characteristics, and for the principal dimensions of ceramic string insulator units of the long
rod type.
This document is applicable to string insulator units for use on overhead lines situated in
lightly polluted areas, and the creepage distances given in Table 1 have been established
accordingly, using the IEC TS 60815-2 recommendation of 16 mm/kV for pollution level I 27,8
mm/kV for SPS class. However, shorter creepage distances may be used are applicable for
use in some non-polluted areas. If specific operating conditions require or allow non-standard
(longer or shorter) creepage distances, the mechanical characteristics as well as the lengths
L (see Clause 4) of this document should are intended to be used unless the need for
exceptionally long creepage distances requires values of L greater than those given in Table
1. In the case of special requirements, e.g. very heavy polluted areas and for other particular
or extreme environmental conditions, it may be necessary for certain dimensions to be
changed.
NOTE As far as reasonably applicable, this document may is also applicable to be applied to
similar insulator units outside the scope of this standard, such as insulators for electric
traction lines. This document does not include tests on insulators and dimensions of end
fittings.
NOTE Ball and socket couplings are covered by IEC 60120, clevis and tongue couplings by
IEC 60471.
NOTE 1 For the definition of site pollution levels severity, see applicable part of IEC TS 60815.
NOTE 2 The term "ceramic" is used in this document to refer to porcelain materials and, contrary to North
American practice, does not include glasses.
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 60071-1:1993, Insulation co-ordination – Part 1: Definitions, principles and rules
IEC 60120:1984, Dimensions of ball and socket couplings of string insulator units

– 6 – IEC 60433:2021 RLV © IEC 2021
IEC 60383-1:1993, Insulators for overhead lines with a nominal voltage above 1 000 V – Part
1: Ceramic or glass insulator units for AC systems – Definitions, test methods and acceptance
criteria
IEC 60471:1977, Dimensions of clevis and tongue couplings of string insulator units
IEC 60672-1:1995, Ceramic and glass insulating materials – Part 1: Definitions and
classification
IEC 60672-3:1997, Ceramic and glass insulating materials – Part 3: Specification for
individual materials
IEC 60815:1986 Guide for the selection of insulators in respect of polluted conditions
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
long rod insulator
suspension or tension insulator consisting of an approximately cylindrical insulating part
provided with sheds and equipped at the ends with external metal fittings
Note 1 to entry: The insulator is designed in such a manner that the shortest puncture path through solid
insulating material is at least equal to half the arcing distance. Therefore it is a class A insulator according to
IEC 60383-1.
4 Characteristics, dimensions and type of long rod insulators
String insulator units of the long rod type are characterised by the following specified
characteristics:
– the standard lightning impulse wit
...