8.10
Cable shielding and routing
To comply with EMC requirements, it is especially important to ensure that cables are routed so
that they are adequately separated from other cables and that components are mounted an
adequate distance away. Always used shielded cables for the following:
• Line supply cables from line filter via line reactor to Line Module
• All motor cables (if necessary, including cables for motor holding brake)
• Cables for "fast inputs" of the Control Unit
• Cables for analog direct voltage/current signals
• Signal cables for encoders
• Cables for temperature sensors
Supplementary conditions
• You can apply measures that provide comparable results. This includes e.g. routing cables
behind the mounting plates or with appropriate clearances. This excludes measures that
relate to the design, installation, and routing of motor power cables and signal cables.
• If unshielded cables are used between the line supply connection point and line filter,
carefully ensure that no cables with interference are routed in parallel.
• Always route power cables and signal cables separately. For this purpose, it is practical if you
arrange the various cables according to cable groups. You can combine cables belonging to
a group to form a bundle. You must route the various cable groups with the necessary
distance between them. A minimum clearance of 20 cm has proven itself in practice. As an
alternative, shield connection plates equipped with multiple contact points can be used
between the cable bundles.
• All cables inside the cabinet must be routed as closely as possible to parts connected with
cabinet ground, such as a mounting plate or cabinet wall. Adequate shielding is provided
using sheet steel ducts or when cables are routed between sheet steel partitions, e.g.
between the mounting plate and rear panel.
• Keep all cables as short as possible to minimize the antenna effect.
• Signal and power cables may cross each other (if absolutely necessary), but must never be
routed closely to one and other in parallel over longer distances.
• Route all signal cables away from strong magnetic fields (motors, transformers) with a
minimum clearance of 20 cm. As an alternative to maintaining a clearance, you can use
shield connection plates equipped with multiple contact points.
• Wherever possible, avoid routing unshielded cables in the immediate vicinity of sources of
interference, e.g. transformers. Route all shielded and unshielded signal cables connected to
the drive lineup well away from strong external magnetic sources (e.g. transformers, line
reactors). In both cases, a clearance of ≥ 300 mm is usually sufficient.
Shield support
You must connect cable shields as close as possible to conductor connection points to ensure a
low-impedance connection with the cabinet ground.
Control cabinet design and EMC booksize
8.10 Cable shielding and routing
Booksize power units
136
Equipment Manual, 01/2022, 6SL3097-6AC30-0BP0