04-01-2011, 04:50 PM
Lightning Protection Zones
A lightning protection zone is an area in which a similar electromagnetic environment can be described. A significant change in this environment occurs at the boundary of a lightning protection zone. A zone boundary may be established by a structure exhibiting a certain degree of electromagnetic shielding or the placement of a surge protective device.The concepts of lightning zones and boundaries are sometimes misunderstood and poorly defined.
i hope this page may help you little
http://engnetglobaltips/Electrical/Lightning/ele_lightning_2.aspx