Siemens SENTRON - Type S Selective

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4.4.8 Type
S
selective
In order to achieve selective tripping in the case of seriesconnected residual
current protective devices in the event of a fault scenario, both the rated residual
current I
Δn
and the tripping time of the devices must be staggered. The different
permissible break times of the standard and selective residual current protective
devices can be taken from  gure 13. Appropriate staggering of the rated residual
currents can also be seen in  gure 13. Type
S
selective residual current protective
devices also have a very high current withstand capability of 5 kA (8/20 μs current
waveform). They are identi ed by the symbol
S
.
Residual current protective devices
Figure 13: Layout of different residual current protective devices and their tripping
times