Characteristics of hollow pressurised and unpressurised ceramic and glass insulators for use in electrical equipment with rated voltages greater than 1000 V
This Technical Specification applies to
- ceramic and glass hollow insulators intended for general use in electrical equipment;
- ceramic hollow insulators intended for use with a permanent gas pressure in switchgear
and controlgear.
They are intended for indoor and outdoor use in electrical equipment, operating on alternating
current with a rated voltage greater than 1 000 V and a frequency not greater than 100 Hz or
for use in direct current equipment with a rated voltage greater than 1 500 V.
This specification specifies the dimensional and mechanical characteristics of the hollow
insulator, which are essential for interchangeability of the hollow insulator of the same type. It
is not the object of this specification to prescribe electrical characteristics because they are
dependent on the apparatus of which the hollow insulator ultimately forms a part. However,
standard lightning impulse withstand voltage which is provided in IEC 60071-1 is described
only for reference for classification purpose.
This specification applies to hollow insulators for use in electrical equipment in clean areas or
lightly polluted areas, where seismic qualification is not required. For use in areas
characterised by heavy pollution levels and for other particular or extreme environmental
conditions such as seismic force, it may be necessary for certain dimensions to be changed.
The hollow insulators covered by this specification are:
a) straight type hollow insulators with metal fittings on both ends;
b) taper type hollow insulators with metal fittings on both ends;
c) straight type hollow insulators without metal fittings;
d) taper type hollow insulators without metal fittings.
The hollow insulators are intended for use in electrical equipment, for example:
- circuit-breakers;
- instrument transformers;
- surge arresters;
- bushings;
- cable sealing ends;
- switch-disconnectors;
- disconnectors;
- earthing switches;
- capacitors.
There may be some cases that hollow insulators whose design can strongly be influenced by
other components of specific equipment, for example, active parts of circuit-breakers. For
such cases, the hollow insulators can be separately designed, depending on respective
requirements of such equipment and not be covered by this specification.
NOTE 1 Hollow insulators not prescribed in this specification can also be applied to electrical equipment,
depending on specific requirements of the equipment. However, if similar insulators are available in this
specification, it is preferable to apply them.
NOTE 2 For general recommendations for design and tests of the hollow insulators, see IEC 62155
NOTE 3 For characteristics of hollow insulators for use in polluted areas, reference can be made to IEC 60815-
1and IEC 60815-2.