The present report describes controlled source electromagnetic sounding using a power distribution line. The line connects a generator with two grounding networks, through which current is injected into the subsurface. The resulting electric field on the surface is measured using electrodes driven into the ground. The electrodes are located at a distance from the line which is comparable with its length. The measurements were conducted 2012-10-11. An effective electric environment model has been calculated from the measured data. The model admits estimating the depth of current penetration into the ground in case of an earth fault in the power grid. In addition, the electric field strength on the surface in the region surrounding the power line can be estimated.