User Manual SICLOCK GPS1000
12
Version 1.0
Order number 2XV9450-1AR82-BA
3.3.
Inducting effect during lightning strikes
The second important parameter of influence on the choice of location is the induction effect which arises from lightning
conductors or building parts where current flows through.
When lightning strikes a lightning conductor, within very a few hundred nanoseconds, voltages of several megavolts are built
up, which result in conducted currents of up to several 10000 amps with correspondingly sharp current leading edges (de-
pending on the inductive resistance of the conductor). Correspondingly strong are the
fields which at a 2 meter distance to the antenna or antenna cable produce induction voltages in the kilovolt range.
Furthermore, when the distance is too short, there is a danger of flashover from the lightning conductor to parts of the an-
tenna unit.
3.4.
Choosing a safe location
From the knowledge outlined in the previous chapter, the factors below should be taken into account when choosing a loca-
tion, with regards to safety against lightning strikes:
1.
Antenna and antenna cable should in principle 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.
Lead the antenna cable inside the building the shortest way.
3.
Lay the antenna cable in principle at right angles to lightning conductors which are
nearby, as then the induction effect is at its lowest.
4.
The 2m distance from lightning conductors to antenna cables laid inside the building
must be enforced, as for many walls there is still a danger of the lightning striking
through the wall.
5.
Install the lightning protection module for conduction of induced surge voltage in-
side the building, directly on the entry of the antenna cable.
3.5.
Installation of the lightning protection module 2XV9450-1AR83
The lightning protection module 2XV9450-1AR83, provided for the conduction of induction voltage (not included under the
scope of delivery of SICLOCK GPS1000) consists of a base part and a lightning conductor module which can be connected
into the basis part. The basis part is connected to the earth cable via the DIN rail supplied with the unit. Basically, it should
be installed inside, at the place where the antenna cable enters the building. Ideally at this point of entry, there should be a
straight connection lead to an own earth foundation.
Several changes of direction with small radii and also rolling up the reserve cable before the earth foundation are ex-
tremely detrimental to the conduction effect.
For details of installation, please see the instructions enclosed with the lightning protection module.
