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Figure 7.5.2.9 Lightning current arrester at the transition from LPZ 0 A to LPZ 1

When installing lightning current arresters at the transition current stress per core is lower in case of multi-core cables
from LPZ 0 A to LPZ 1, it must also be observed that the rec- than in case of cables with some few single cores. For further
ommended place of installation at the service entrance box information please see chapter 6.3.
can frequently only be implemented in agreement with the Therefore, only surge protective devices for which a discharge
utility (new: distribution network operators). The requirements current (10/350 µs) is specified may be used (Figure 7.5.3.1).
on lightning current arresters in main power supply systems If equipotential bonding is established for lines at the transi-
are laid down in the guideline by the VDN (Association of tion from LPZ 0 B to LPZ 1, surge protective devices with an
German Network Operators) 2004-08: “Überspannungs- impulse current discharge capacity up to 20 kA (8/20 µs) are
Schutzeinrichtungen Typ 1. Richtlinie für den Einsatz von sufficient since no galvanically coupled partial lightning cur-
Überspannungs-Schutzeinrichtungen (ÜSE) Typ 1 in Haupt- rents will flow though them.
stromversorgungssystemen“ [Surge Protective Devices Type
1 – Guideline for the use of surge protective devices (SPDs)
Type 1 in main power supply systems] and IEC 60364-5-53
(HD 60364-5-534) (Figures 7.5.2.7 to 7.5.2.9).

7.5.3 Equipotential bonding for information
technology systems
LPZ 0 A – LPZ 1
Lightning equipotential bonding from LPZ 0 A to LPZ 1 must be
implemented for all metal systems entering a building. Infor-
mation technology lines must be protected by lightning current
arresters with an adequate discharge capacity as close as pos-
sible to their entry point into the structure. A general discharge
capacity up to 2.5 kA (10/350 μs) per core of information
technology lines is required for the transition from LPZ 0 A to
LPZ 1. However, this general approach is not used when rating
the discharge capacity for installations with multiple informa-
tion technology lines. After calculating the partial lightning cur-
rent to be expected for an information technology cable (see
IEC 62305-1 (EN 62305-1)), the lightning current must be di-
vided by the number of single cores in the cable in order to
determine the impulse current per core. The partial lightning Figure 7.5.3.1 Use of BLITZDUCTOR XT combined arresters

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