Three basic earth electrode arrangements are used:
• Type arrangement
• Type arrangement
• Foundation earth electrodes
Type arrangement
This consists horizontal vertical earth
electrodes, connected each down conductor
fixed the outside the structure.
Type arrangement
This arrangement essentially fully connected
ring earth electrode that sited around the
periphery the structure and contact with
the surrounding soil for minimum 80% its
total length (i. The agreement of
the operating authority owner the
relevant systems should obtained prior to
any bonding taking place.
The standard recommends single integrated
earth termination system for structure,
combining lightning protection, power and
telecommunication systems. 20% its overall length may be
housed say the basement the structure and
not direct contact with the earth).
Separation (isolation) distance the external LPS
A separation distance (i. the electrical insulation)
between the external LPS and the structural metal
parts essentially required.
A good earth connection should possess the
following characteristics:
• Low electrical resistance between the electrode
and the earth.
This can achieved placing lightning
conductors sufficiently far away from any
conductive parts that have routes leading into the
structure.
It comprises conductors that are installed in
the concrete foundation the structure. This will minimize
any chance partial lightning current being
introduced internally the structure.—
Technical reference
IEC/BS 62305-3 Physical damage to
structures life hazard
Earth termination system
The earth termination system vital for the
dispersion lightning current safely and
effectively into the ground.
114 FURSE® EARTHING LIGHTNING PROTECTION
QUALIT SOLUTIONS FOR SAFEGUARDING PEOPLE, STRUCTURES AND SERVICES
.e. The choice of
material for the earth electrode and its
connections vital importance. So, the lightning discharge strikes
the lightning conductor, cannot ‘bridge the gap’
and flash over the adjacent metalwork. any
additional lengths electrodes are required
they need meet the same criteria those for
type arrangement. The lower the earth electrode
resistance the more likely the lightning current
will choose flow down that path preference
to any other, allowing the current conducted
safely and dissipated the earth
• Good corrosion resistance. Foundation earth electrodes
can used augment the steel reinforcing
foundation mesh.e.
Foundation earth electrodes
This essentially type earthing arrangement. will be
buried soil for many years has be
totally dependable
The standard advocates low earthing resistance
requirement and points out that the earthing
system should have overall resistance to
earth path Ohms less
