Dahua D-SD59225DB-HC Installation Manual page 13

Table 2-2 Installing lightning protection devices outdoors
No. Description
1 Video lightning conductor.
2 Communication lightning conductor.
3 Power supply lighting conductor.
4 Impedance of the cable connected to the grounding wire should be less than 4 Ω.
5 The radius is 60 m.
6 Lightning conductor.
7 Steel tube.
Figure 2-3 Installing lightning protection devices outdoors (2)
R: The radius of the circle, and R = 60 m.
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L1: The length of the pole that holds the lightning conductor.
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L2: The length of the rail that holds the Device.
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H: The length of the lightning conductor.
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To get the value of L1, you need to use the formula:
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