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
Installation altitudes
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.
Altitude [m]
2000
3000
4000
5000
Rated voltage 440 V [V]
440
387
343
300
Rated voltage 690 V [V]
690
607
538
470
Rated uninterrupted current [% I
n
]
100
98
93
90
Rated ultimate short-circuit
breaking capacity AC I
cu
[% I
cu
@U
e
]
100
100
100
100
See also
Installation in the switchboard (Page 147)
4.1.5
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.
Current
rating I
n
[A]
Ambient temperature
< 40 °C
45 °C
50 °C
55 °C
60 °C
65 °C
70 °C
630
100%
100%
100%
100%
100%
100%
100%
800
100%
100%
100%
100%
100%
100%
100%
1000
100%
100%
100%
100%
100%
100%
100%
1250
100%
100%
100%
100%
100%
100%
100%
Note
All values refer to the withdrawable breakers and fixed-mounted breakers and to the
conductor cross-sections stated in the table in Section Installation in the switchboard
(Page 147) and to the overriding standard IEC 60947.
The values do not apply to all mounting conditions for circuit 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).