If lightning strikes and the lightning current flows into
an air-termination rod and earth via the external
lightning protection system, approximately 50% the
lightning current enters the building via the building’s
equipotential bonding system and hence couples gal-
vanically.External lightning protection
system
Earthing system
Main earthing busbar
Transmitter
Data cable carrying lightning
current
Galvanic coupling into data cable via the external lightning protection system
"Galvanic coupling"
When lightning current, e.
Coupled lightning currents are not always due the
external lightning protection system: principle, any
external cable that ends the house can couple light-
ning currents, for example, strike substation or
an exposed cable connected the house.
TBS
Blitzschutz-Leitfaden
2018
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en
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2020/01/10
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2020/01/10
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Chapter The internal lightning protection system
.g. Lightning
current can also enter the building via the telecommu-
nications cable. metal rodent guard can turn even
an EMC-insensitive fibre optic cable into conductor
of lightning current. the case light-
ning strike, passes into the cable directly, this is
known galvanic coupling
