Siemens Sinamics G120P Operating Instructions Manual page 60

Electrical installation
4.5 EMC compliant design
Use anti-interference elements
● If relays, contactors, and inductive or capacitive loads are connected, the switching relays
or contactors must be provided with anti-interference elements.
Cable installation
● Cables that are subject to or sensitive to interference should be laid as far apart from
each other as possible.
● All cables are to be laid as close as possible to grounded enclosure parts such as
mounting plates or cabinet frames. This reduces both noise radiation and interference
injection.
● Reserve cores of signal and data cables must be grounded at both ends to achieve an
additional shielding effect.
● Long cables should be shortened or laid in noise resistant areas to avoid additional
connecting points.
● If it is impossible to avoid crossing cables, conductors or cables that carry signals of
different classes must cross at right angles, especially if they carry sensitive signals that
are subject to interference.
– Class 1:
– Class 2
– Class 3:
Shield connection
● Shields must not be used to conduct electricity. In other words, they must not
simultaneously act as neutral or PE conductors.
● Apply the shield so that it covers the greatest possible surface area. You can use ground
clamps, ground terminals, or ground screw connections.
● Avoid extending the shield to the grounding point using a wire (pigtail) because this will
reduce the effectiveness of the shield by up to 90%.
● Attach the shield to a shield bar directly after the line inlet into the cabinet. Insulate the
entire shielded cable and route the shield up to the device connection, but do not connect
it again.
60
unshielded cables for ≤ 60 V DC
unshielded cables for ≤ 25 V AC
shielded analog signal cables
shielded bus and data cables
operator panel interfaces, incremental/absolute encoder lines
unshielded cables for > 60 V DC and ≤ 230 V DC
unshielded cables for > 25 V AC and ≤ 230 V AC
unshielded cables for > 230 V AC/DC and ≤ 1000 V AC/DC
Inverter cabinet units
Operating Instructions, 12/2014, A5E32923362A