Installing network components in cabinets
3.3 Guidelines for setting up networked automation systems in buildings
Passive network components
System Manual, 02/2013, C79000-G8976-C282-01
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If cables are installed permanently, it is advisable to remove the insulation of the shielded
cable and to establish contact on the shield/PE conductor bar.
Note
If there is a potential difference between the grounding points, an illegally high
compensating current can flow through the shield grounded at both ends. To rectify the
problem, do not, under any circumstances, open the shield of the bus cable.
This problem can be solved in the following ways:
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Install an additional bonding conductor parallel to the bus cable that takes over the shield
current.
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Use fiber-optic cable instead of electrical cable (safest solution).
Establishing shield contact
When contacting the cable shields, please note the following points:
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Secure the braided shield with metal cable clamps.
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The clamps must make good and large-area contact with the shield.
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Contact SIMATIC NET twisted-pair cables only using the braided copper shield and not
the aluminum foil shield. The foil shield is connected to a plastic foil to increase tearing
strength and is therefore non-conductive.
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Contact the shield with the shielding bar directly at the point at which the cable enters the
cabinet.