Input Parameters
Typical values: 25°–60° depending on mast height and class
Results
Protection Radius
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Protection Area (Circle)
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Mast Height
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Method Used
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Formula Applied:
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Reverse Calculation — Required mast height for a desired radius:
Protection Zone Visualization
Frequently Asked Questions
How do you calculate lightning protection radius from mast height?
The lightning protection radius is calculated using the rolling sphere method formula: r = √(h × (2R − h)), where h is the mast height and R is the rolling sphere radius (20m, 30m, 45m, or 60m depending on the protection level per IEC 62305). Alternatively, the protection angle method uses r = h × tan(α), where α is the protection angle that varies based on mast height and protection class.
What is the rolling sphere radius for different lightning protection levels?
According to IEC 62305, Level I protection uses a rolling sphere radius of 20 meters, Level II uses 30 meters, Level III uses 45 meters, and Level IV uses 60 meters. A smaller rolling sphere radius provides a higher level of protection but results in a smaller protection radius for the same mast height.
What mast height is needed to protect a 15-meter radius area?
Using the rolling sphere method with Level III protection (R=45m), you would need a mast height of approximately 15.3 meters to achieve a 15-meter protection radius. The exact height depends on the protection level chosen. The relationship is h = R − √(R² − r²), where R is the sphere radius and r is the desired protection radius.