Free tools

Free lightning protection calculators

Five free calculators for common lightning protection figures under IEC 62305, NFPA 780 and AS 1768. No sign-up, and each one cites the clause, table or equation behind its result.

Each tool answers one question: whether NFPA 780 Annex L says a structure needs protection, how often a structure is struck under IEC 62305-2, which class of LPS a risk calls for, how far metal must stay from the LPS, and how much ground one mast protects.

The four calculators under /tools run on the same standard engines as Lumex™ itself, and show the working with every step cited. The rolling sphere calculator works its geometry in your browser. None of them replaces a full risk assessment or a protection design to the standard.

All three standards

Rolling sphere method calculator

A free calculator for the protected radius of a single mast, with IEC 62305, NFPA 780 and AS 1768 sphere radii in feet or metres.
NFPA 780

NFPA 780 risk assessment calculator

A free Annex L screen: compare the yearly strikes to the structure, N_D, with the tolerable frequency N_C, with every step cited to NFPA 780-2026.
IEC 62305

IEC 62305 collection area and N_D calculator

A free calculator for the collection area A_D, a roof protrusion's A_D' and the yearly strike count N_D under IEC 62305-2:2024 Annex A.
IEC 62305

Lightning protection level selector

Enter the risk components from an IEC 62305-2:2024 assessment and see the weakest class of LPS that brings R within R_T, with its design values.
IEC 62305

Separation distance calculator

A free IEC 62305-3:2024 calculator for the separation distance s: pick the class of LPS, the material and the down conductors, enter l and check the gap.

The standards behind each figure are explained in the guides, and every term is defined in the glossary.

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The tools answer one figure. Lumex™ runs the whole assessment, to a report you can sign

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