LIGHTNING PROTECTION FOR MASTS
5 (8)
Uppgjord (även faktaansvarig om annan) -
Prepared (also subject responsible if other)
Nr -
No.
KL/ECS/S/LT Magnus Lindahl
ECS/S/LT-96:5037
Dokansv/Godk -
Doc respons/Approved
Kontr -
Checked
Datum -
Date
Rev
File
KI/ECS/S/LTC
1996-06-04
A
Error! Unknown switch argument.
Since an installation for lightning protection is a relatively major investment, it must
function for many years. Corrosion should be avoided, as far as possible, through
selection of the correct materials.
Above ground level, copper, aluminium and galvanized steel can be used, but these
should not be mixed in the same installation.
Earth electrodes and conductors buried in the ground may be of copper or galvanized
steel. Aluminium should not be used in soil.
Copper should be used if a non - insulated copper cable has previously been
installed at a distance of less than two metres. This may, for example be an earth line
associated with electrical installations or existing earth electrodes.
Galvanized steel should be used if there are objects in the ground, in direct contact
with the soil, which are not made of copper, for example lead - covered cable, steel or
cast - iron water pipes.
If it is not possible to guide the choice of materials, insulation must be created for one
or the other or both metals to ensure that the distance through the soil, in the
electrical sense, is more than two metres.
Connections or branches of the component of the installation above ground level
should be carried out so that moisture cannot collect at the connection point. This is
particularly important if differing materials must be joined. Attachment components
must also be selected with possible corrosion effects in mind.
Dimensions
Conductors used in lightning conductor systems must be sufficiently strong - both
mechanically and chemically.
The minimum recommended area for conductors and earth electrode leads laid in or
above the ground are: copper cable, 25 mm²; steel cable 50 mm²; aluminium cable
(not underground) 50 mm².
Conductors connecting surge voltage protectors with lightning conductors or mains
earths at common terminals must be at least 6 mm copper wire with insulation. The
wire should be laid by the shortest possible route, max. 10 m
The connection between the lightning earth electrode and the common mains neutral
terminals must be so dimensioned that any earth leakage currents do not cause heat
damage or high voltages loss through induction. The link between the radio rack and
the earth electrode must not be less than 10 mm² copper.
NOTE:
All connections involving the mains power supply must be carried out by an
authorized electrician and with the approval of the power supply company.
