Special Service Conditions - ABB Uniswitch Operation And Maintenance Manual

1.3.2 Special service conditions

Special service
conditions
ABB
Uniswitc h Operation and
Maintenanc e Manual
At site altitudes above 1000 m, the effects of the reduction in dielectric
strength of the air on the insulation level must be taken into account
(please refer to IEC standard 60694).
Increased ambient temperatures must be compensated for in the design
of the busbars and branch conductors as well as for the components,
otherwise the current carrying capacity will be limited.
! When switchgears are operated in areas with high
humidity and/or major rapid temperature fluctuations,
there is a risk of dew deposits which must remain an
exception in normal service conditions for indoor
switchgear.
! Preventive action (e.g. fitting electric heaters) must be
taken in consultation, with the manufacturer, to avoid this
condensation phenomenon and any resulting corrosion
or other adverse effects. The control of the heaters
depends on the relevant project and details must be taken
from the order documents.
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UNI S14GB 05-02