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8.1 Power supply systems (as part edly carrying lightning currents of 10/350 μs wave form
of the lightning protection zone without destructing the equipment. These type 1 SPDs are
called lightning current arresters. Their function is to prevent
concept according to IEC 62305-4 destructive partial lightning currents from entering the elec-
(EN 62305-4)) trical installation of a building.
The installation of a lightning and surge protection system
for electrical installations represents the latest state of the To protect against surges, type 2 SPDs with a discharge ca-
art and is an indispensable infrastructural condition for the pacity of about some 10 kA (8/20 μs) are used at the transi-
trouble-free operation of complex electrical and electronic tion from LPZ 0 B to LPZ 1 and higher or LPZ 1 to LPZ 2 and
systems without consequential damage. The requirements higher.
on SPDs which are necessary for the installation of such a
lightning and surge protection system as part of the light- The last link in the lightning and surge protection system
ning protection zone concept according to IEC 62305-4 for power supply systems is the protection of terminal de-
(EN 62305-4) for power supply systems are defined in vices (transition from LPZ 2 to LPZ 3 and higher). The main
IEC 60364-5-53 (HD 60364-5-534). function of a type 3 surge protective device installed at this
point is to protect against overvoltages arising between the
conductors of an electrical system, in particular switching
SPDs used as part of the fixed building installation are clas-
sified into type 1, 2 and 3 surge protective devices according overvoltages.
to the requirements and stress on the places of installation A summary of the different functions, arrangements and re-
and are tested to IEC 61643-11 (EN 61643-11). quirements on arresters is given in Table 8.1.1.
The highest requirements with respect to the discharge ca-
pacity are placed on type 1 SPDs. These are used as part of 8.1.1 Characteristics of SPDs
the lightning and surge protection system at the boundary Maximum continuous operating voltage U c
from LPZ 0 A to LPZ 1 and higher as shown in Figure 8.1.1. The maximum continuous operating voltage (previously: rated
These surge protective devices must be capable of repeat- voltage) is the root mean square (rms) value of the maximum

external LPS lightning current arrester sub-distribution board surge arrester terminal devices
main distribution board

F1 meter
L1
L2
Wh L3
PEN SEB N
PE
F2 F3

MEB local EBB

Figure 8.1.1 Use of arresters in power supply systems (schematic diagram)

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