Rolling Sphere Method Calculator |best| <AUTHENTIC · Cheat Sheet>

The sphere’s radius is not arbitrary. It is derived from the formula, which relates to the peak lightning current. The most common standard (IEC 62305 and NFPA 780) defines protection levels (I to IV) with corresponding sphere radii:

This is the industry standard.

: A 12 m high surge arrester in a substation needs Level II protection (r = 30 m). You have existing 18 m lightning masts. rolling sphere method calculator

p=R−R2−(d/2)2p equals cap R minus the square root of cap R squared minus open paren d / 2 close paren squared end-root If the height of your structure is greater than ( ), the area between the rods is . Steps to Protect Your Structure The sphere’s radius is not arbitrary

The Rolling Sphere Method is based on the . This model assumes that lightning does not travel in a straight line indefinitely. Instead, the "leader" (the initial stroke of lightning) has a specific striking distance. : A 12 m high surge arrester in