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Electrical Systems

Lightning Protection System

External & internal lightning protection per IEC 62305 / NFPA 780.

Category
Electrical Systems
Subcategory
Protection
Applicable standards
3
Issuing bodies
3

Description

External & internal lightning protection per IEC 62305 / NFPA 780.

Applicable Standards (3)

IEC — 1 standard

IEC 62305 (series) Protection against lightning
Edition: Parts 1–4, 2010–2013 Region: Global
Lightning protection system design — risk assessment, air termination, down conductors, earth termination, internal LPS.
Key requirements (7)
  • Lightning protection: Parts 1 (general), 2 (risk), 3 (physical), 4 (electrical/electronic).
  • Lightning protection level (LPL): I (highest, 99% capture), II (97%), III (91%), IV (84%).
  • Air termination: rolling sphere method (radius 20/30/45/60 m for LPL I/II/III/IV).
  • Mesh method: 5/10/15/20 m mesh size for LPL I/II/III/IV.
  • Down conductors: spacing ≤ 10/10/15/20 m around perimeter.
  • Earth termination: type A (radial / vertical) or type B (ring) — < 10 Ω target typical.
  • Surge protection: SPD coordination (Type 1 / 2 / 3) at incomer, sub-distribution, equipment.

NFPA — 1 standard

NFPA 780 Standard for the Installation of Lightning Protection Systems
Edition: 2023 Region: USA, Global
Lightning protection system design (US counterpart to IEC 62305).

BIS — 1 standard

IS/IEC 62305 (series) Protection Against Lightning
Edition: Adopted IEC 62305 Region: India
Indian adoption of IEC 62305 lightning protection.