Siemens SIMATIC NET PROFIBUS Owner's Manual page 268

Installing LAN Cables
Install LAN cables separately
To prevent accidental damage to LAN cables, they should be clearly visible and
should be separate from all other wiring and cables. To improve EMC, it is often
advisable to install the LAN cables in a separate cable channel or in conductive,
metal tubes. Such measures also make it easier to localize a faulty cable.
C-6
PROFIBUS Networks SIMATIC NET
6GK1970-5CA20-0AA1 Release 2 05/2000