Siemens SENTRON - Page 56

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In the case of Siemens residual current protective devices, rated switching capacity
and rated residual switching capacity are not differentiated and nor are rated con-
ditional short-circuit current and rated conditional residual short-circuit current.
The reason for this is that the values for the residual and short-circuit currents can
be identical in the relevant cases.
The use of miniature circuit breakers or circuit breakers instead of the specied
fuses will result in markedly lower rated values in some cases due to the higher
throughput values until the circuit is disconnected. A direct specication for the
permissible rated current of these circuit breakers cannot be given here due to
the great differences in design and tripping characteristics. But the maximum
permissible rated current of the allocated overcurrent protective device can be
determined in consideration of the maximum permissible limit values of the
residual current operated circuit breaker. The rated current of the allocated over-
current protective device can be determined based on the maximum permissible
short-circuit back-up fusing according to table 5 specied on the residual current
operated circuit breakers. In the process, the following maximum values must be
complied with for series 5SM3 residual current operated circuit breakers:
Design maximum permissible
short-circuit back-up fuse
maximum
I²t value
maximum current
peak value
5SM3 63 A 25.000 A²s 6.0 kA
5SM3 80 A 40.000 A²s 7.0 kA
5SM3 100 A 70.000 A²s 7.5 kA
5SM3
125 A 94.000 A²s 8.0 kA
Design maximum permissible
short-circuit back-up fuse
maximum
I²t value
maximum current
peak value
5SV 63 A 15.620 A²s 5.4 kA
5SV 80 A 25.410 A²s 6.2 kA
5SV
100 A 44.880 A²s 8.9 kA
Notes on installation and use