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7.6 Equipotential bonding at the
boundary of LPZ 0 and LPZ 2
A
7.6.1 Equipotential bonding for metal installa-
tions
See chapter 7.5.1.
SPD
0/1/2
7.6.2 Equipotential bonding for power supply
systems
LPZ 0 A – LPZ 2 Figure 7.6.2.1 Only one SPD (LPZ 0/1/2) required (LPZ 2 integrated
Due to the design of the structure, it can often not be avoid- in LPZ 1)
ed to implement an LPZ transition from LPZ 0 A to LPZ 2 at a
boundary, especially in case of compact installations (Figure
7.6.2.1).
The implementation of such an LPZ transition places high
demands on the surge protective devices used and their sur-
roundings. Besides the parameters as described in 7.5.2, a
protection level must be achieved which ensures safe opera-
tion of equipment and systems of LPZ 2. A low voltage pro-
tection level and high limitation of the interference energy
transmitted by the arrester form the basis for safe energy
coordination with surge protective devices in LPZ 2 or with
surge-limiting components in the input circuits of the equip-
ment to be protected. With a voltage protection level ≤ 1.5 kV,
the spark-gap-based combined arresters of the DEHNventil Figure 7.6.2.2 DEHNventil M TT 255

external
LPS lightning current arrester surge arrester

?

terminal device
SPD class SPD class
(test level 1)
combined arrester

shielded cable
?
?

terminal device
SPD class (test level 1)
Figure 7.6.3.1 Combination guide for Yellow/Line SPD classes (see also Figure 7.8.2.2)

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