Siemens SINAMICS S150 NEMA, Operating Instructions Manual, Page: 68 / 862

Electrical installation
4.5 EMC-compliant design
Enclosed Drives
66
Operating Instructions, 12/2018, A5E36652151A
Cable installation
● Cables that are subject to or sensitive to interference should be laid as far apart from
each other as possible.
● All cables must 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:
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 cables
– Class 2:
Unshielded cables for > 60 V DC and ≤ 230 V DC
Unshielded cables for > 25 V AC and ≤ 230 V AC
– Class 3:
Unshielded cables for > 230 V AC/DC and ≤ 1000 V AC/DC
Shield connection
● Shields must not be used to conduct electricity. In other words, they must not
simultaneously act as neutral or ground (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 its entry into the cabinet. Insulate the entire
shielded cable and route the shield up to the device connection, but do not connect it
again.
I/O interfacing
● Create a low-impedance ground connection to other cabinets, system components, and
distributed devices with the largest possible cross-section (at least 16 mm²).
● Ground unused lines at one end in the cabinet.
● Select the greatest possible distance between the power and signal cables, but at least
20 cm. The greater the distance over which the cables are routed in parallel, the greater