Application planning
4.1 Types of installation and installation locations
3VA27 molded case circuit breakers & 3WL10 air circuit breakers
142 Manual, 10/2018, L1V30499596002-01
An installation altitude above 2000 m can result in higher temperatures on the switching
devices. The lower density of air can significantly reduce heat dissipation. The arcing
behavior and the conductivity of the density-dependent ionized gas mixture are also less
favorable at greater altitudes. This makes it necessary to decrease rated operational voltage
and the rated uninterrupted current.
Rated voltage 690 V [V] 690 607
538 470
Rated uninterrupted current [% I
n
Rated ultimate short-circuit
breaking capacity AC I
cu
[% I
cu
@U
e
]
100
100
100 100
Installation in the switchboard (Page 147)
Current reduction
4.1.5.1
Current reduction depending on the ambient temperature on the 3WL10
The circuit breaker itself has no derating within the application temperatures.
Note
All values refer to the withdrawable breakers and fixed
-mounted breakers and to the
-sections stated in the table in Section Installation in the switchboard
147) and to the overriding standard IEC 60947.
The values do not apply to all mounting conditions for cir
cuit breakers and may deviate
depending upon factors such as packing density, ventilation, internal separation of the
installation, etc.
Please observe the applicable overriding guidelines (e.g.
IEC 61439).
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