ERICORE MAXIMUM LENGTHS
The construction of the nVent ERICO
Ericore cable has been carefully designed
and tested to withstand a
250
kV potential
difference under lightning conditions. When
compared to a conventional bare copper
conductor, the Ericore cable has relatively
low characteristic impedance. This lowers
the induced voltage on the Ericore cable for
much longer lengths. The maximum length
of single Ericore cable is limited by its rated
voltage. While longer lengths of Ericore
cable can be used, the risk of damaging the
Ericore cable increases when approaching
the maximum length.
The risk can be determined by considering
the statistical nature of lightning. The
percentage of lightning strikes that are
severe enough to damage the Ericore cable
at a given length are based on the known
parameters of the Ericore cable. A cable that
is “X” meters long will withstand “Y” percent
of lightning strikes as follows:
•
69
m (
226
ft.) of Ericore handles
95
% of
lightning strikes (i.e. one strike in twenty
will damage the cable)
•
87
m (
285
ft.) of Ericore cable handles
80
% of lightning strikes (i.e. one strike in
five will damage the cable)
•
94
m (
308
ft.) of Ericore handles
75
% of
lightning strikes (i.e. one strike in four will
damage the cable)
INSTALLATION METHODS FOR
ERICORE EXCEEDING
70
M
There are two methods to extend the length
of Ericore
1. Parallel splicing - use two Ericore cables
in parallel with the Dual Terminal Adaptor
kit that allows you to install two Ericore
cables at the top of the mast
(See Figure
34
), or
2. Series splicing - Connect two or more
Ericore cables in series between the air
terminal and the first grounding point.
Terminate each section to a busbar that
is electrically connected to the structure
(see Figure
35
).
Parallel Splicing
By installing two Ericore cables, the current
from the lightning strike will split into each
cable. It is recommended that at the base of
the supporting mast, the Ericore cables are
routed down opposite sides of the building
for better distribution of the lightning
energy. Running the Ericore cables close
together is not recommended. If the paths
taken by each cable are similar in length,
then each cable length can be up to two
times the maximum single length of Ericore
cable. If the lengths of each Ericore cable
are different, then the maximum length of
shorter Ericore cable must comply with the
below equations:.
For
a
>
1
and
L
1
= a
L
M
,
L
2
≤ bL
M
where b =
1
1
a
1
- —
Key
L
1
Length of the shorter Ericore cable
L
2
Length of the longer Ericore cable
L
max
Maximum length of the shorter
Ericore cable
L
M
Maximum length of a single run of
Ericore cable
Parallel splicing of Ericore cable should
only be used for structures whose height
is less than or equal two times the
maximum length of a single run of Ericore
cable. For taller structures, series splicing
must be used.