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1:3
H 500 m
A M
3H A I
A D
4000 m
3H A DJ
L H 40 m A L H J L J

W
W
W J
L

L L
Figure 3.2.3.2 Equivalent collection area A D Figure 3.2.3.3 Equivalent collection area A M , A L , A I for indirect lightning strikes to the structure
for direct lightning strikes to
an isolated structure

Relative location of the structure C D
Structure surrounded by higher objects 0.25
Structure surrounded by objects of the same height or smaller 0.5
Isolated structure: no other objects in the vicinity (within a distance of 3H) 1
Isolated structure on a hilltop or a knoll 2

Table 3.2.3.1 Location factor C D

Routing C I
Overhead line 1
Buried 0.5
Buried cables running entirely within a meshed earth-termination system (see 5.2 of IEC 62305-4 (EN 62305-4)) 0.01
Table 3.2.3.2 Installation factor C I

Transformer C T
Low-voltage power, telecommunication or data line 1
High-voltage power line ( with high-voltage / low-voltage transformer) 0.2
Table 3.2.3.3 Line type factor C T

Environment C E
Rural 1
Suburban 0.5
Urban 0.1
Urban with tall buildings (higher than 20 m) 0.01
Table 3.2.3.4 Environmental factor C E

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