Pick the lightning protection level. A lower number is stricter: the test ball is smaller, so the rod must cover more closely.
How the check works
Test ball (IEC 62305-3, 5.2.2.2). A ball of radius R is tried against the structure from every direction the search covers. It may touch only the ground and air terminals. If it can touch a roof, edge or corner, that spot is exposed.
Result words. “Covered” means no contact was found in a sampled search. It is not proof of continuous coverage. “Marginal” means the answer flips when R changes by 2 %. “Not covered” means a contact was found.
Rods are modelled as zero-diameter metal lines over their full length. The mast is assumed to be continuous metal. Neither is verified.
Walls. Ordinary side impacts are negligible up to 60 m (5.2.3), but significant facade protrusions still matter and are not modelled. The optional side check covers the top 20 % of bare walls on structures above 60 m.
Supplier radius is manufacturer data. IEC 62305-3 does not recognise it. Results in that mode are not an IEC assessment.
Not assessed: protection-angle method, mesh method, catenary wires, parapets, overhangs, ridges, roof equipment, accessible or flammable roofs, hazardous areas. Separation, bonding, down conductors, earthing and components are not verified.