LIGHTNING PROTECTION METHOD IN STEEL FRAME BUILDING

PROBLEM TO BE SOLVED: To provide a lightning protection apparatus that can prevent damages to electrical equipment caused by reverse flow of induced current, when an indirect lightning stroke occurs. SOLUTION: A cable 3 of a computer 2 and the protected equipment side of a lightning arrester 9 are connected via an arrester conductor 10, and the steel beam 7 between supports 5 and the earth side of the lightning arrester 9 are connected with a conductor (ground wire) 8 via a ground box G. The steel beam 7 has a high electrical resistance (small conductor) relative to the steel support 4 or is insulated, and is not grounded directly to the ground 12. That is, even if an indirect lightning stroke strikes a building, current or static electricity is not generated in the steel beam 7. Thus, a surge current accompanying induced lightning stroke is prevented from flowing in reverse, from the steel beam 7 to the computer 2 side through the lightning arrester 9. COPYRIGHT: (C)2003,JPO