dehn HVI power Conductor Installation Instructions Manual page 16

The operator must classify the relevant structure into Ex zones (explosion protection document). This
Â
Ex zone classification is binding for the installer of the lightning protection system.
It is not allowed to install HVI
Â
HVI power Conductors may be installed in Ex zone 1 (gas, vapour, mist) or Ex zone 21 (dust) pro-
®
Â
vided that these installation instructions are observed.
If lightning currents flow through the HVI
Â
conductive sheath due to the low-power capacitive displacement current at remote earthing points.
The shorter the distance between the earthing points and the semiconductive sheath, the lower is
this potential.
If materials such as grain or flour are stored in silos or liquid substances in buildings, the various
Â
materials require different ignition energies to cause an explosion. In order to avoid that the diffe-
rent hazardous materials have to be assessed with regard to their ignition energies, it is necessary
to observe special installation instructions.
If these installation instructions are observed, discharge (sparking) is safely prevented when light-
Â
ning current flows through the HVI
4
power Conductors in Ex zones 0 and 20.
®
power Conductor, a potential arises on the outer semi-
®
power Conductor.
®