Siemens GPS1000 Radio Clock 2XV9450-1AR82 - Manual (Page 15)

User Manual SICLOCK GPS1000
Order numberr 2XV9450-1AR82-BA Version 2.0 15
4.3. Inducting effect during lightning strikes
Another important parameter influencing the choice of antenna location is the induction effect which arises from
lightning conductors or building parts where lightning current flows through.
When the lightning hits into a lightning conductor, within a few hundred nanoseconds, voltages of several
megavolts are built up, which result in conducted currents up to several 10000 amps with correspondingly steep
surge pulse edges (depending on the inductive resistance of the lightning conductor). Leading to powerful elec-
trical fields which at a 2 meter distance to the antenna or antenna cable produce induction voltages in the kilo-
volt range.
Furthermore, when the distance is too short, there is a danger of flashover from the lightning conductor to parts
of the antenna unit.
4.4. Choosing a safe location
Keeping in mind the the previous chapter and the safety against lightning strikes, the following facts should be
taken into account when choosing a antenna location.
1. Antenna and antenna cable should always be installed at least 2 meters away
from lightning conductors and areas in danger of being struck by lightning in
conformity with Fig 7 and Fig 8 and in the green area. Never in the red area!!!
2. Install the antenna cable the shortest possible way from the antenna to the
inside of the building.
3. Install the antenna cable orthogonal to lightning conductors nearby, because
the induction effect is then minimal.
4. The 2m distance from lightning conductors to antenna cables shall be en-
forced also inside the building, because an electrical breakthroug can occur
even through a wall.
5. Install the lightning protection module at the inside of the building as close as
possible to the entry point of the antenna cable.
4.5. Installation of the lightning protection module 2XV9450-1AR83
The lightning protection module 2XV9450-1AR83 (not included in the scope of delivery of SICLOCK GPS1000)
consists of a base part and a lightning conductor module which can be plugged into this basis. The basis part is
connected to the earth cable via the DIN rail supplied with the unit. Basically, it should be installed inside the
building, as close as possible to the entry point of the antenna cable. Ideally there should be a straight connec-
tion lead to the earth foundation electrode.
Several changes of direction, tight bends and coiling up the cable previous to the earth foundation electrode
are extremely adveresly to the conduction effect.
For details of installation, please see the manual enclosed with the lightning protection module.