The current induced along a vertical metallic post and the buried horizontal wire is obtained by solving the corresponding homogeneous integro-differential equations. The excitation given in the form of lightning channel current is taken into account via the appropriate boundary conditions at wires ends. The influence of a lossy half-space is taken into account by means of Sommerfeld integrals appearing in the integral equation kernel. These integral equations are solved by the finite element method, while Sommerfeld integrals are evaluated via the exponential approximation technique.