Kathrein ARA 20 Handbuch Seite 11

Antenna earthing/lightning protection
Because of the serious consequences if the
work is not done properly, earthing and lightning
protection work may be performed only by
specially trained electricians!
Never perform earthing and lightning
protection work if you are not a specialist
with the appropriate skills!
The instructions printed here are not an
invitation to non-specialists to perform
earthing and lightning protection work on their
own account; they are meant solely as additional
information for the specialists whom you employ!
The antenna must be erected to DIN EN 60728-11 and earthed
as specifi ed. Only these antennas are exempt from the earthing
requirement:
– more than 2 m below the edge of the roof
– and at the same time less than 1.5 m from buildings.
For earthing, the mast must be connected by means of a suitable
ground conductor to the lightning protection system of the building,
using the shortest route. If no lightning protection system is
available: to the building's earth conductor.
Connection to the lightning protection system may be made only
by a qualifi ed lightning protection system installation engineer.
a) Suitable as ground conductors are
– a single solid wire with a cross-section of at least 16 mm
copper, at least 25 mm 2
b) Unsuitable as ground conductors are
- the outer conductor of the antenna cable
- metallic domestic installations (such as the metal pipework
of a water or heating system), since the permanence of the
electrical connection cannot be guaranteed
- or the shielding conductor or neutral conductor of the
mains power supply.
c) Routing of ground conductors
• Antenna cables and earthing conductors must not be
routed through rooms used for storing easily fl ammable
substances (such as hay or straw) or in which an
explosive atmosphere can develop (such as gases, vapours).
• If the antenna is used in an integrated antenna system
(e. g. a distribution system), the earthing measures must also
be designed in such a way that earthing protection is still
maintained if individual units are removed or replaced.
aluminium or at least 50 mm
Grounding
Erdungs-
conductor
leitung
Equipoten-
Potenzial-
tial bonding
ausgleichs-
cable
leitung
Grounding
Erdungs-
connection
anschluss
2
2 steel.
The standard says that
within the hatched area
antenna grounding
is not compulsory.
Hazards may be caused not only by thunderstorms (lightning),
but also by static charges and short circuits in the connected
units.
For safety reasons therefore in general for all antenna systems
an equipotential bonding conductor of 4 mm² copper should be
provided.
The cable screens of all coaxial antenna downlink cables
must be connected to the mast with an equipotential bonding
conductor.
5 / 6
Equipotential bonding rail
Potenzialausgleichsschiene
Mains connection
Netzanschluss
Equipoten-
Potenzial-
tial bonding
ausgleichs-
cable
leitung
Equipotential bonding rail
Potenzialausgleichsschiene
1.5m