Subclause 1.1 of IEC 62271-1:2007 is not applicable, and is replaced as follows:.
This part of IEC 62271 applies to three-pole units for public and industrial distribution systems
which are functional assemblies of switches including switch-disconnectors and currentlimiting
fuses designed so as to be capable of
– breaking, at the rated recovery voltage, any current up to and including the rated shortcircuit
breaking current;
– making, at the rated voltage, circuits to which the rated short-circuit breaking current
applies.
It does not apply to fuse-circuit-breakers, fuse-contactors, combinations for motor-circuits or
to combinations incorporating single capacitor bank switches.
In this standard, the word “combination” is used for a combination in which the components
constitute a functional assembly. Each association of a given type of switch and a given type
of fuse defines one type of combination.
In practice, different types of fuses may be combined with one type of switch, which give
several combinations with different characteristics, in particular concerning the rated currents.
Moreover, for maintenance purposes, the user should know the types of fuses that can be
combined to a given switch without impairing compliance to the standard, and the
corresponding characteristics of the so-made combination.
A switch-fuse combination is then defined by its type designation and a list of selected fuses
is defined by the manufacturer, the so-called “reference list of fuses”. Compliance with this
standard of a given combination means that every combination using one of the selected
fuses is proven to be in compliance with this standard.
The fuses are incorporated in order to extend the short-circuit breaking rating of the
combination beyond that of the switch alone. They are fitted with strikers in order both to open
automatically all three poles of the switch on the operation of a fuse and to achieve a correct
operation at values of fault current above the minimum melting current but below the minimum
breaking current of the fuses. In addition to the fuse strikers, the combination may be fitted
with either an over-current release or a shunt release.
This standard applies to combinations designed with rated voltages above 1 kV up to and
including 52 kV for use on three-phase alternating current systems of either 50 Hz or 60 Hz.
Fuses are covered by IEC 60282-1.
Devices that require dependent manual operation are not covered by this standard.
Switches, including their specific mechanism, shall be in accordance with IEC 62271-103
except for the short-time current and short-circuit making requirements where the currentlimiting
effects of the fuses are taken into account.
Earthing switches forming an integral part of a combination are covered by IEC 62271-102.