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Air-termination systems and rods tors (down conductors, air-termination conductors, earth en-
Air-termination rods with a length of 1 m (e.g. installed in a tries) with one another or to an installation. Depending on
concrete base in case of flat-roofed buildings) up to 25 m (e.g. the type of clamp and clamp material, many different clamp
in case of biogas plants) are typically used as air-termination combinations are possible. These depend on the type of con-
system. ductor routing and the relevant material combinations. Type
IEC 62561-2 (EN 62561-2) specifies the material combinations of conductor routing means whether the clamp connects the
of air-termination systems and down conductors with one an- conductor or conductors in a cross or parallel arrangement.
other and with structural parts, minimum cross-sections and A lightning current load causes electrodynamic and thermal
permissible materials including their electrical and mechanical forces which act on the clamp and must be withstood by the
properties. In case of air-termination rods with larger heights, clamp. The resulting forces are heavily dependant on the type
the bending resistance of the air-termination rod and the sta- of conductor routing and the clamp connection. Table 5.8.1
bility of complete systems (air-termination rod in a tripod) must shows materials which can be combined without causing con-
be verified in a static calculation. The required cross-sections tact corrosion. The combination of different materials with one
and materials are then selected based on this calculation. The another and their different mechanical strengths and thermal
requirements / parameters of the relevant wind zone form the properties have different effects on the connection compo-
basis for this calculation. nents when lightning current flows through them. This par-
ticularly becomes evident in case of connection components
Testing of connection components made of stainless steel (V4A) where high temperatures occur
Connection components, often simply referred to as clamps, due to the low conductivity as soon as lightning currents flow
are used for lightning protection systems to connect conduc- through them. Therefore, a lightning current test in compliance

Steel Aluminium Copper StSt (V4A) Titanium Tin
Steel (StZn) yes yes no yes yes yes
Aluminium yes yes no yes yes yes
Copper no no yes yes no yes
StSt (V4A) yes yes yes yes yes yes
Titanium yes yes no yes yes yes
Tin yes yes yes yes yes yes
Table 5.8.1 Possible material combinations of air-termination systems and down conductors with one another and with structural parts

Figure 5.8.3 New and artificially aged components

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