Siemens SINAMICS S120 Manual page 126

Cabinet design
6.9 Cable shielding and routing
Shield support
The cable shields must be connected as close to the conductor terminal connections as
possible to ensure a low-impedance connection with cabinet ground. For power cables from
Siemens in which the shield is connected to the connector shell (see relevant catalog), this is
a sufficiently good shield support.
For components that do not have any special shield connection or where the shield
connection is not sufficient, the cable shields can be connected to the metal mounting plate
using hose clamps and toothed rails. The cable length between the shield contact point and
the terminals for cable conductors must be kept as short as possible.
Shield connection plates with preprepared clip contacts are available for contacting the
shields for power cables of Line Modules and Motor Modules. Up to a module width of
100 mm (inclusive), these plates are part of the scope of delivery of the components, or they
are integrated in the connector.
Routing 24 V cables
When routing 24 V cables, the following must also be observed:
● A maximum of one conductor pair may be bundled together.
● 24 V conductors must be routed separately from other cables and conductors that could
conduct the operating current.
● 24 V cables must never be routed parallel to power cables.
● 24 V cables as well as power cables should be routed to the components so that they
never cover ventilation slots.
Conditions of use for 24 V cables
● Ambient temperature: 55 °C
● Conductor limit temperature: ≤ 70° C for operation with the rated load current
● Max. cable length: 30 m for 24 V power supply cables and for signal lines without
additional connections
124
Power Units in Booksize C/D-Type Format
Manual, 12/2018, 6SL3097-5AC20-0BP0