27
Figure 10: Type B frequency-dependent tripping current
To protect against res caused by ground-fault currents, the use of residual
current protective devices with a rated residual current of up to 300 mA has pro-
ven itself to be effective. This is derived from the assumption that approximately
70 W is suf cient to cause a re. The tripping values of the SIQUENCE universal
current-sensitive Type B RCCB increase with higher frequencies. However, since
residual current contains high-frequency and low-frequency components (see
section 5.3.2), an effective contribution to re protection in the case of ground-
fault currents can also be achieved with a tripping characteristic which rises with
the frequency. The positive effect of the increasing tripping current is a higher
degree of operational safety for the system as a whole, since leakage currents
from capacitors can lead to a reduced level of unwanted tripping of the RCCB.
Note: The lines illustrated are typical patterns. Deviations up to the limit
values of the standard are possible.
Frequency response characteristics of the SIQUENCE Type B current-sensitive RCCB
10.000
1.000
100
10
1 10 100 1.000 10.000
Tripping current (mA)
Frequency (Hz)
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