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Figure 7.7.2.2 DEHNflex M surge protective device for final circuits Figure 7.7.2.3 Multipole DEHNguard M TT surge arrester

7.7.3 Equipotential bonding for information
technology systems
LPZ 1 – LPZ 2 and higher
Further measures must be taken at the LPZ transitions in build-
ings to reduce the interference level (Figure 7.7.3.1). Since
terminal devices are typically installed in LPZ 2 or higher, the
protection measures must ensure that the residual interference
level is below values the terminal devices can cope with. This
can be achieved by:
¨ Installation of surge protective devices in the vicinity of
terminal devices
¨ Integration of the cable shields in the equipotential bond-
ing system
¨ Connection of the low-impedance equipotential bonding
system of the SPD for information technology systems with
the terminal device and SPD for power supply systems
¨ Energy coordination of the upstream SPD with the SPD and
terminal device
¨ Distance of at least 130 mm between the telecommunica-
Figure 7.7.3.1 Protection of industrial electronic equipment tion lines and gas discharge lamps
(e.g. a PLC) by BLITZDUCTOR XT and SPS Protector
¨ Distribution board and data distributor should be located
in different cabinets
7.7.2.2) or form the infrastructural basis for the proper op- ¨ Low-voltage and telecommunication lines must cross at an
eration of a device or system (Figure 7.7.2.3). Thus, different
types of surge protective devices can be used at the LPZ transi- angle of 90 °
tions from LPZ 1 to LPZ 2 and higher. ¨ Cable crossing along the shortest possible route

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