抄録
Distribution of lightning current in a building when it is directly hit by lightning is calculated by directly solving Maxwell’s equations with the help of Numerical Electromagnetic Code （NEC-4）. Lightning current shunts into wiring on each floor of the building unevenly through SPD’s, and current into wiring on the top and the bottom floors is the largest. SPD’s of high energy rating are necessary for apparatuses equipped on the top and bottom floors, irrespective of the height of a building.
