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and DEHNvenCI family are ideally suited for such applications that both ends of the cable shield are integrated in the equipo-
and provide optimal protection of terminal devices even for tential bonding system to prevent that interference is injected.
sensitive equipment with a rated impulse withstand voltage of
1.5 kV (overvoltage category I according to IEC 60364-5-53 The use of combined arresters is recommended, if
(HD 60364-5-534)). Consequently, they allow the user to com- ¨ The terminal devices are close to the point where the cables
bine lightning equipotential bonding and coordinated protec- enter the building
tion of terminal devices, namely energy coordination of a type 1, ¨ Low-impedance equipotential bonding can be established
type 2 and type 3 arrester within the first 5 m, in a single de- between the protective device and the terminal device
vice (Figure 7.6.2.2).
¨ The line from the protective device to the terminal device is
continuously shielded and earthed at both ends
Since, for the LPZ transition from LPZ 0 to LPZ 2, it is inevita-
ble that both lightning protection zones are adjacent to each ¨ A particularly cost-effective solution is required
other, a high degree of shielding at the zone boundaries is
absolutely imperative. In principle, it is recommended to keep The use of lightning current arresters and surge arresters is
the area of the adjoining lightning protection zones LPZ 0 and recommended, if
LPZ 2 as small as possible. If the structure permits it, LPZ 2 ¨ There are long cable distances between the protective de-
should be equipped with an additional zone shield which is vice and the terminal device and the injection of interfer-
installed separately from the lightning current carrying zone ence is to be expected
shield at the zone boundary LPZ 0 as can be seen in Figure ¨ The SPDs for power supply and information technology sys-
7.6.2.1 so that LPZ 1 covers a large part of the installation. The tems are earthed via different equipotential bonding bars
attenuation of the electromagnetic field in LPZ 2 implemented ¨ Unshielded lines are used
by this measure eliminates the need for consistent shielding of
all lines and systems in LPZ 2. ¨ High interference can occur in LPZ 1

7.6.3 Equipotential bonding for information 7.7 Equipotential bonding at the
technology systems boundary of LPZ 1 and LPZ 2 and
LPZ 0 A – LPZ 2 higher
A lightning current arrester from LPZ 0 to LPZ 1 discharges 7.7.1 Equipotential bonding for metal
a large part of the interference energy, thus protecting the installations
installation in the building from damage. However, it is fre-
quently the case that the level of residual interference is still This equipotential bonding system must be installed as close
too high to protect the terminal devices. In a further step, ad- as possible to the point where the lines and metal installations
ditional surge protective devices are installed at the LPZ transi- enter the zone (zone transition).
tion from LPZ 1 to LPZ 2 to limit the interference to a residual Likewise, all systems and conductive parts must be connected
voltage level which is adjusted to the dielectric strength of the as described in chapter 7.5.1.
terminal device (Figure 7.8.2.1). The conductors should be routed along the shortest possible
route (low impedance).
Ring equipotential bonding in these zones allows low-imped-
If equipotential bonding is implemented from LPZ 0 to LPZ 2, ance connection of the systems to the equipotential bonding
the place of installation must be chosen and the partial light- system.
ning current of the single cores and shields must be deter- Figure 7.7.1.1 illustrates the preparation for connecting a
mined as described in chapter 6.3. cable trough to the ring equipotential bonding system at the
However, the requirements on an SPD to be installed at the LPZ zone transition.
transition and the requirements on the wiring downstream this
transition change. A combined arrester which is energy-coordi- The following metal installations must be integrated in the
nated with the terminal device must be used (Figure 7.6.3.1). equipotential bonding system:
Combined arresters have an extremely high discharge capacity
and a low residual interference level to protect the terminal de- ¨ Metal cable ducts
vices. Furthermore, it must be observed that the outgoing line ¨ Shielded cables and lines
from the protective device to the terminal device is shielded and ¨ Building reinforcement

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