This paper proposes a partial element equivalent circuit (PEEC) model for t
he analysis of the electromagnetic environment inside a building during dir
ect or nearby lightning strike. A PEEC model for the lightning protection s
ystem (LPS) is developed in conjunction with a PEEC model for braided coaxi
al cables, A two-step matrix solution of the whole set of equations describ
ing the LPS and cables allows one to predict the current distribution in th
e downconductors and the induced voltages and currents on the cables' shiel
d and loads. Results are given in frequency and time domain for direct and
nearby lightning strikes and for different positions of the cables inside t
he LPS volume.