When laying cable in a switch cabinet, the following additional instructions apply: All incoming cable shields must be connected to ground as close as possible to where they enter the cabinet. The clamps must ensure large-area connection of the cable shield to the cabinet's frame ground.
Grounding of the cable shield at the entry in the cabinet
Even for cables of the same category, the laying of internal lines and inserted cables in parallel as far as their ground fixing should be avoided. For good contact, coated or galvanically stabilized earth rails are ideal. Painted surfaces should be avoided when laying the earth. If insulation is removed from the cable, make sure that the shield is not damaged.
If there is insufficient room for the minimum distances, cables of different categories should be separated with metallic channels.
If PROFIBUS devices are connected inside a cabinet with a bit rate over 1.5 Mbit/s, a minimum cable length of 1 m is recommended. This means that any loops must be laid.