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Foundation earth electrodes minimum dimensions of 30 mm x 3.5 mm. It must be ob-
Foundation earth electrodes make technical and economic served that this material must be covered with a concrete
sense and are required in the German Technical Connection layer of at least 5 cm (corrosion protection). The foundation
Conditions (TAB) published by German distribution network earth electrode must be connected to the main earthing bus-
operators. They are part of the electrical installation and fulfil bar in the wind turbine. Corrosion-resistant connections must
essential safety functions. For this reason, they must be in- be established via fixed earthing terminals or terminal lugs
stalled by or under supervision of an electricians. made of stainless steel (V4A). Moreover, a ring earth elec-
The metals used for earth electrodes must comply with the trode made of stainless steel (V4A) must be installed in the
materials listed in Table 7 of lEC 62305-3 (EN 62305-3). The ground.
corrosion behaviour of metal in the ground must be observed
at any time. Internal lightning protection measures
Foundation earth electrodes must be made of galvanised or
non-galvanised (round or strip) steel. Round steel must have ¨ Earthing and equipotential bonding measures
a minimum diameter of 10 mm, while strip steel must have ¨ Spatial shielding and separation distance

Nr. Art.-Nr.
tower
Equipotential bonding bar
for industrial use 472 209
Wire, stainless steel
concrete foundation 860 010
(V4A)
Fixed earthing terminal, 478 011
stainless steel (V4A)
Cross unit, 319 209
foundation earth electrode stainless steel (V4A)
Strip, 30 mm x 3.5 mm,
St/tZn 810 335
Pressure U-clamp 308 031
MAXI MV clamp, 308 040
UL467B-approved
ring earth electrode

Figure 9.16.3 Earth-termination system of a wind turbine

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