Number of down conductors, by dividing the building perimeter into typical intermediate distances It is present and is at least 2. Typical spacing according to TS EN 62305-3: LPL I–II 10 m, LPL III 15 m, LPL IV 20 m. For example, a 40×20 m structure (perimeter 120 m) requires approximately 8 down conductors for LPL III.

Number ≈ Perimeter / distance between blocks (LPL I–II 10 m, III 15 m, IV 20 m), at least 2
Example calculation: 40×20 m structure (perimeter 120 m), LPL III (intermediate spacing 15 m) → 120/15 = 8 → 8 down conductors; at least 2, priority given to corners.

Number of Downstream (Downstream) Conductors

See the approximate number of down conductors required according to the building environment and protection level (LPL) (TS EN 62305-3).

Building surroundings
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Typical distance
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Number of down conductors
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Notes: Number ≈ perimeter / typical intermediate distance (TS EN 62305-3 Table 4: LPL I–II 10 m, III 15 m, IV 20 m), at least 2. Corners and entrances are given priority; The actual site layout is determined based on building geometry, natural components, and risk analysis. This tool provides a preliminary estimate.
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How is it calculated?

  1. Enter the length and width (m) of the structure.
  2. Select the Level of Protection (LPL).
  3. Press Calculate; the perimeter, spacing, and number of down conductors will be displayed.

Frequently Asked Questions

How is the number of down conductors determined?
The building perimeter is divided into typical spacing intervals corresponding to the Level of Protection (LPL); the result is rounded up to a minimum of 2.
What is the minimum number of down conductors required?
According to TS EN 62305-3, every structure must have at least 2 down conductors; they should be evenly distributed around the perimeter if possible, with priority given to corners.
Are natural components considered down conductors?
Yes, natural components such as continuous metal columns/facades can be used as down conductors; this affects the design.

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 →