TS EN 62305-3 defines four protection levels. Rolling sphere radius. LPL I=20 m, II=30 m, III=45 m, IV=60 m; The mesh spacing is 5/10/15/20 m respectively; the typical down conductor spacing is 10/10/15/20 m. The required level is determined by risk analysis.

Conserved ground radius: rp = √(2·r·h − h²) (h ≤ r)
Example calculation: LPL III → rolling sphere 45 m, net 15×15 m, down conductor ~15 m. A single rod at a height of 8 m protects an area with a radius of ≈ 25.6 m on the ground (rp = √(2×45×8 − 8²)).

Lightning Protection Level (LPL) Parameters

Select the protection level according to TS EN 62305-3; view the rolling sphere radius, mesh spacing, and down conductor spacing. Optional: calculate the protected radius on the ground by entering the pole/rod height.

Rolling sphere r
–
Mesh size
–
Down conductor spacing
–
Protected ground radius
–
Notes: The values correspond to the protection levels of TS EN 62305-3 (Tables 2 & 4). The protection angle depends on the height. (62305-3, Figure 1) and a single value cannot be given. The conserved ground radius is calculated by the rolling sphere method rp=√(2·r·h−h²) (for h≤r) — single rod approximation. The required level of protection comes from risk analysis. (See Lightning Risk Preliminary Assessment); this tool displays the geometric parameters of the selected level.
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How is it calculated?

  1. Select the protection level (LPL I–IV).
  2. Enter the (optional) pole/rod height (m).
  3. Press Show; the geometric parameters and protected radius will be displayed.

Frequently Asked Questions

What is the radius of a rolling sphere?
It is a geometric method that defines the protection zone, varying according to the protection level (LPL I 20 m, II 30 m, III 45 m, IV 60 m).
Why is the protection angle not provided?
The protection angle depends on the building height (TS EN 62305-3, Figure 1) and cannot be expressed by a single value.
Which protection level should I choose?
The required LPL (Lightning Plaque) is determined based on the lightning risk analysis results of the structure; this tool shows the parameters of the selected level.

Related tools and services

This tool and its content are for general informational purposes only; they do not constitute a binding inspection/declaration of conformity. Definitive results will be determined through on-site inspection in accordance with relevant legislation and standards. Get a quote →