Use In It Networks - Siemens SENTRON 3VL System Manual

6.5

Use in IT networks

Use of the 3-VL circuit breakers in IT networks
The 3VL circuit breakers up to frame size VL1250 have been tested in accordance with
IEC / EN 60947-2, Annex H (testing sequence for circuit breakers for IT systems) up to a
maximum (V
certificates of conformance testing (Page 346). The 3VL8 cannot be used in the IT network.
The SIEMENS SENTRON VL circuit breakers for system protection, optionally with thermal
overload and electromagnetic short-circuit releases, or electronic overcurrent trip units, are
suitable for use in IT networks. The circuit breakers also meet the requirements of the
IEC 60947-2 standard Annex H (DIN EN 60947-2, Annex H). The respective options are
required here, and the necessary safety clearances (ventilation clearances) must be
observed.
Selection criteria for circuit breakers
The devices are always dimensioned and selected independently of the relevant network
type. The circuit breaker is always selected in accordance with the maximum occurring
short-circuit current in the IT network. The device is selected in accordance with the relevant
I values of the 3VL circuit breaker.
cu
Table 6- 3 I values depending on V
cu
V 3VL1
e
I at 240 V 65 kA
cu
I at 415 V 55 kA
cu
I at 690 V 8 kA
cu
The values in the above table apply provided one of the subsequent requirements is met:
● The IT network is operated with a grounded neutral cable,
● the plant operator takes the necessary precautions to prevent the occurrence of a double
ground fault on the incoming or outgoing side of the circuit breaker.
3VL molded-case circuit breakers
System Manual, 03/2009, 110 0110 - 02 DS 01
max.) voltage of 690 V AC. The switching capacities can be found in the
i
e
3VL2 3VL3
65 kA 65 kA
55 kA 55 kA
12 kA 12 kA
3VL4 3VL5
65 kA 65 kA
55 kA 45 kA
15 kA 20 kA
Application planning
6.5 Use in IT networks
3VL6 3VL7
65 kA 65 kA
50 kA 50 kA
20 kA 20 kA
3VL8
65 kA
50 kA
20 kA
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