A direct strike occurs when lightning directly hits a structure or a cable attached to a structure. The energy contained within the lightning travels through the structure or cable to the earth. A number of techniques including earthing systems, air terminals and down conductors are used to protect structures against direct strikes.
A lighting protection system provides a means by which this discharge may enter or leave earth without passing through and damaging non-conducting parts of a structure, such as those made of wood, brick, tile or concrete. A lightning protection system does not prevent lightning from striking - it provides a means for controlling it and preventing damage by providing a low resistance path for the discharge of lightning energy.