IT Baseline Protection Manual - The Information Warfare Site

Safeguard Catalogue Infrastucture Remarks
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S 1.39 Prevention of transient currents on shielding
Initiation responsibility: Head of IT section
Implementation responsibility: Site/Bldg Technical Service; physical network
operator
There are various ways of preventing transient currents on the shielding of
data lines in buildings:
Transient currents can be avoided in the TN-C network by only linking IT
appliances via shielded data lines which are connected to a common electrical
distribution system. This must be checked each time the data network is
extended.
In the event that this is not possible, transient currents can be avoided by only
providing shielding on one side of the data line. In case of alteration to the
data network, only suitable cables should be used (cables with shielding only
on one side).
The optimum and safest method is to design the power distribution network in
the entire building as a TN-S network. Here, the PE line and the N line are fed
separately after the potential equalisation bar (PEB). Individual safeguards on
IT equipment are then generally not necessary. Chapter S 1.28 Local
uninterruptable power supply should be observed, however, regarding the
creation of a new TN-S network for the connected equipment.
The following diagrams show the formation of transient currents on shielding
and the possible safeguards:
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IT-Baseline Protection Manual: Oktober 2000