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Requirements for External Lightning Protection Components

Components used for installing the external lightning protection
system shall meet the mechanical and electrical requirements,
as specified in the EN 62561-x standard series. Lightning protec-
tion components are categorised according to their function, for
example connection components (EN 62561-1), conductors and
earth electrodes (EN 62561-2).
Testing of conventional lightning protection components
Metal lightning protection components (clamps, conductors, air-termina-
tion rods, earth electrodes) exposed to the elements have to be subjected
to artificial ageing/conditioning prior to testing to verify their suitability
for the intended application. In accordance with EN 60068-2-52 and EN
ISO 6988 metal components are subjected to artificial ageing and tested
in two steps. Figure 1:
Test in a salt mist
Natural weathering of lightning protection components and chamber.
exposure to corrosion

Step 1: Salt mist treatment
This test applies to components or devices for installation in saline at-
mospheres. The specimens are tested with severity level 2 in a salt mist
chamber (Figure 1) for three days. Test level 2 consists of three spraying
phases of 2 h each, using a 5% sodium chloride solution (NaCl) at tem-
peratures between 15 °C and 35 °C followed by storage at a relative
+2
humidity of 93 –3 % and a temperature of 40 ±2 °C for 20 to 22 hours in
accordance with EN 60068-2-52.
Step 2: Humid sulphurous atmosphere treatment
This test is to evaluate the resistance of materials or objects to con-
densed humidity containing sulphur dioxide in accordance with EN ISO
6988.
The test is carried out in a test chamber (Figure 2) in seven test cycles of
-6
24 h each in a sulphur dioxide concentration of 667 x 10 (±24 x 10 )
-6
of the volume. Each cycle has a heating period of 8 h at a temperature
of 40 ±3 °C in a humid, saturated atmosphere followed by a rest peri-
od of 16 h. After that, the humid sulphurous atmosphere is replaced. Figure 2:
Both components for outdoor use and components buried in the ground Test in a Kesternich
are subjected to ageing / conditioning. For components buried in the chamber.
ground additional requirements and measures have to be considered.
No aluminium clamps or conductors may be buried in the ground. If
stainless steel is to be buried in the ground, only high-alloy stainless
steel may be used, e.g. StSt (V4A). In accordance with the German
DIN VDE 0151 standard, StSt (V2A) is not allowed. Components for indoor
use such as equipotential bonding bars do not have to be subjected
to ageing / conditioning. The same applies to components which are
embedded in concrete. These components are therefore often made of
non-galvanised (black) steel.

Air-termination systems / air-termination rods
Air-termination rods are typically used as air-termination systems. They
are available in many different designs, ranging from 1 m for installation
with concrete base on flat roofs, to telescopic lightning protection masts
with a length of 25 m for biogas plants. material combinations are decisive in this respect. The kind of conductor
EN 62561-2 specifies the minimum cross sections and the permissible routing describes how a clamp connects the conductors in cross or par-
materials with the corresponding electrical and mechanical properties for allel arrangement.
air-termination rods. In case of a lightning current load, clamps are subjected to electrody-
In case of air-termination rods with larger heights, the bending resistance namic and thermal forces which highly depend on the kind of conductor
of the air-termination rod and the stability of complete systems (air-ter- routing and the clamp connection. Table 1 shows materials which may
mination rod in a tripod) have to be verified by means of a static calcu- be combined without causing contact corrosion.
lation. Selection of the required cross sections and materials is based The combination of different materials with one another and their differ-
on this calculation. The wind speeds of the relevant wind load zone also ent mechanical strengths and thermal properties have different effects
have to be taken into account for this calculation. on the connection components when lightning current flows through
them. This is particularly evident for stainless steel (StSt) connection
Testing of connection components components where high temperatures occur due to the low conductivity
Connection components, often simply called clamps, are used as light- as soon as lightning currents flow through them. Therefore, a lightning
ning protection components to connect conductors (down conductor, current test in compliance with EN 62561-1 has to be carried out for all
air-termination conductor, earth entry) to each other or to an installation. clamps. In order to test the worst case, not only the different conductor
Depending on the type of clamp and clamp material, a lot of different combinations but also the material combinations specified by the manu-
clamp combinations are possible. The conductor routing and the possible facturer have to be tested.
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