Description
2.7 Basic unit
3VA27 molded case circuit breakers & 3WL10 air circuit breakers
40
Manual, 10/2018, L1V30499596002-01
Switch disconnectors
Switch disconnectors are devices that meet the insulation requirements of the standard IEC
60947-3 and IEC 60947-2 CBI-Y Annex L.
The switch disconnector has an identical design to the circuit breaker and has the same
dimensions, weights, and optional accessories. However, it differs from the circuit breaker in
that it does not have any protection functions and therefore no electronic trip unit (ETU) and
no internal electronics or current transformer.
The disconnector ensures an insulation clearance between its main contacts in the open
state that isolates all downstream parts of the installation.
If used with an external protection relay with a maximum delay time of 500 ms, the switch
disconnector has a breaking capacity at the maximum rated operational voltage (U
e
) that
corresponds to the value of the one-second rated short-time current (I
cw
). The "non-
automatic air circuit breaker" is sometimes also called a load interrupter switch because it
can switch overcurrents.
3WL10 non-automatic air circuit breakers
3WL10 non-automatic air circuit breakers are only available in classes N and S.
Number of poles
3, 4
Rated operational
voltage
U
e
AC (50/60 Hz)
V
690
Rated insulation
voltage
U
i
AC (50/60 Hz)
V
1000
Rated impulse
withstand voltage
U
imp
kV
12
Isolating features
IEC 60947-3
Current-carrying capacity of the
neutral pole for 4-pole non-
automatic
circuit breakers
% I
n
100
Breaking capacity
N
S
Rated uninterrupted current
(at 40 °C)
I
u
AC (50/60 Hz)
A
630
630
I
u
AC (50/60 Hz)
A
800
800
I
u
AC (50/60 Hz)
A
1000
1000
I
u
AC (50/60 Hz)
A
1250
1250
Rated short-circuit
making capacity up to 690 V
I
cm
disconnector only
kA
88
105
with upstream ACB
air circuit breaker
kA
145
145
Rated short-time
withstand current
I
cw
1 s
kA
42
50
I
cw
3 s
kA
24
36
Utilization category
(according to IEC 60947-3)
AC-23A
AC-23A
Rated conditional
short-circuit current
up to 690 V
I
cc
kA
42
50