nvent ERICO System 3000 - Practical Examples for Long Lengths of Ericore Downconductor; Telecom Towers; Buildings; Proposed Ericore Lengths

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a series connection in the service shaft.
Buildings of height greater than twice the
maximum single length (typically greater
than  m ( ft.) in height) need to use
the series connection method. The nVent
ERICO application engineering group will
determine the allowable lengths of the
lower cable sections, which may be able
to be longer than the upper length, and in
some cases, the lower sections may be
conventional downconductor.
PROPOSED ERICORE LENGTHS
Although the flowchart in Figure  allows
lengths of up to  m ( ft.), ideally
lengths should be limited to  m ( ft.)
to avoid any likelihood of lightning energy
cross-flashing to the structure.
In the case of installations exceeding the
maximum single Ericore cable length, the
advice of the nVent ERICO application
engineering group should be sought. The
following information on the techniques
used is intended as a guide for installers and
to provide background information.
Note: If the number of thunderdays for the
proposed installation site is not known, but the
ground flash density is known, this value can be
converted to thunderdays using the following
table. This resulting value can then be used in
Figure 26 located on the following page.
When to use a twin Ericore arrangement or a
series connected arrangement depends on
the particular circumstance. The following
examples give typical guidance.
TELECOM TOWERS
Most towers would be less than  m
( ft.), or so, in height so that a single
Ericore downconductor would suffice.
However, where the tower is over the
maximum single length but less than twice the
maximum single length (typically  m
( ft.) to  m ( ft.) in height), it is
preferable to run twin Ericore downconductors.
These conductors should ideally run down
opposite legs of the tower and each connect
into the ring earth at the base of the tower.
Alternatively, and less preferably, a single
upper section of typical length  m ( ft.)
could be run from the top of the tower
to a point lower down on the tower, then
bonded to the tower using a waterproofed
lower termination. A conventional lightning
downconductor could be run from this
point down to the base of the tower. This
arrangement helps ensure that the lightning
current bypasses the sensitive electronics
mounted in the antennas on the top half of
the tower.
BUILDINGS
Buildings less than  m ( ft.), or so,
in height are served by a single Ericore
downconductor.
Buildings of height over the maximum single
length but less than twice the maximum
single length (typically  m ( ft.) to
 m ( ft.) in height) may be installed
with either twin Ericore downconductors, or
Practical Examples for Long Lengths of
Ericore Downconductor
Ground flash density
(strikes / km
2
/ year)
Lightning activity
(thunderdays / year)
Up to . 
. to . 
. to . 
. to . 
. to . 
. to . 
. or more 