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alloy stainless steel, e.g. material No. AISI/ASTM 316 Ti, or fixed
earthing terminals (Figure 5.5.2.5).

When installing the foundation earth electrode, the mesh size
must not exceed 20 x 20 m. This mesh size does not depend
on the class of LPS of the external lightning protection system
(Figure 5.5.2.6).

Nowadays, various types of foundations with different designs
and sealing versions are used.
Heat insulation regulations have also influenced the design of
strip foundations and foundation slabs.
If foundation earth electrodes are installed in new structures
based on DIN 18014, the sealing / insulation affects their in-
stallation and arrangement.
Figure 5.5.2.6 Meshed foundation earth electrode
Connecting clamps for reinforcements
Foundation earth electrodes must be connected to the rein-
The modern methods of laying concrete in reinforced concrete forcement of the foundation slab at intervals of 2 m. To do so,
foundations and then vibrating / compacting it ensure that the there are various possibilities.
concrete also “flows” under the earth electrode enclosing it Clamping turned out to be the most cost-effective solution
on all sides if the flat strip is installed horizontally, thus ensur- since this connection can be made easily and quickly on site.
ing corrosion resistance. Consequently, vertical installation of Moreover, according to the latest lightning protection stand-
the flat strip is not required when mechanically compacting ards, reinforcing steel, for example, can be used as a natural
concrete. Figure 5.5.2.4 shows an example of the horizontal component of the down-conductor system. Since the compo-
installation of a flat strip as a foundation earth electrode. The nents of the foundation earth electrode must be connected in
intersections of the foundation earth electrode must be con- such a way that they are permanently conductive and mechan-
nected in such a way that they are capable of carrying currents. ically stable, these connections are efficiently made by means
of screws according to IEC 62561-1 (EN 62561-1) (Lightning
It is sufficient to use galvanised steel for foundation earth elec- protection system components Part 1: Requirements for con-
trodes. nection components). More detailed information on this topic
can be found in chapter 5.8.
Terminal lugs to the outside into the ground must be protected
against corrosion at the point where they leave the structure. Figure 5.5.2.7 gives an overview of the nominal and outer
Suitable materials are, for example, plastic sheathed steel wire diameters as well as the cross-sections of reinforcing steel.
(owing to the break risk of the plastic sheath at low tempera- The outer diameter of reinforcing steel is decisive for selecting
tures, special care must be taken during the installation), high- the connection components / clamps.

Nominal diameter d S Outer diameter d A
The outer diameter
including the ribs is about
d A = 1.15 x d S

Nominal diameter d s (mm) 6 8 10 12 14 16 20 25 28 32 40
Outer diameter including the ribs d A (mm) 6.9 9.2 11.5 13.8 16.1 18.4 23 29 32 37 46
2
Nominal cross-section (mm ) 28.3 50.3 78.5 113.1 154 201 314 491 616 804 1257
Figure 5.5.2.7 Diameters of reinforcing steels

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