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2. Summary
Special operating conditions
The switchgear is suitable for operation in the
WDa type of climate according to IEC 60721-2-1.
Special operating conditions must be discussed
with ABB in advance. For example:
• 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 (Figure 1).
• Increased ambient temperatures must be
compensated in the design of the busbars
and branch conductors, otherwise the
current carrying capacity will be limited.
Note on special climatic operating conditions:
When switchgear is operated in areas with high
humidity and/ or major rapid temperature
fluctuations, there is a risk of dew deposits which
must be excluded under normal operating
conditions for indoor switchgear. Preventive
action (e.g. suitable ventilation and proper air
conditioning of the building or housing, use of
dehumidifying equipment, etc.) must be taken
into consideration with ABB to avoid this
condensation phenomenon and any resulting
corrosion or other adverse effects.
Figure 1: Curve for determining the altitude factor k in
relation to the altitude H
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