Solution - Furuno WR2120 Installation Manual

A.3. Solution
Ways to make a current installation safer.
Lightning protection level definition:
Lightning protection level (LPL) is defined in the regulation based on peak current. LPL will be
selected for installation situations where LPL IV is generally used. Protection area will be made
using rolling sphere, its radius is determined in the Table A.7. Example of an actual condition is
shown in the Figure A.3.
Table A.7: Probability and rolling sphere radius for LPL (IEC 62305-1)
Probability
LPL
for min value
I 0.99
II 0.97
III 0.91
IV 0.84
Figure A.3: Protection of aerials and other external equipment (IEC 62305-4)
Minimum
peak
current [kA]
3
5
10
16
Key
1) lightning rod
2) steel mast with antennas
3) handrails
4) interconnected reinforcement
Key
r) radius of the rolling sphere
1) Lightning rod
2) Steel mast with antennas
3) Handrails
4) Interconnected reinforcement
r) Radius of the rolling sphere
Probability Minimum peak
for max value current [kA]
0.99
0.98
0.95
0.95
57
Rolling sphere
radius [m]
200 20
150 30
100 45
100 60