These application notes on mine electric power systems are based on work done under contract to the Bureau of Mines. The notes are intended to provide ready reference to mine maintenance engineers. The subject covered in the first notes are (1) the measurement of earth resistivity, (2) measurement of ground bed resistance, (3) cable fault location using time domain reflectometry instruments, (4) cable fault location, (5) common splicing errors and how to avoid them, and (6) learning from failed splices. Because this is an active area of research, the Bureau of Mines plans to issue new and updated notes and to distribute them to the holders of the original publication. Additional application notes will include electric transient suppression and additional items on trailing cable splicing.