ALTA wireless AC Current Meters measure the RMS current of an alternating current (AC) system using a current transformer (CT) that wraps around the "hot" wire of a two wire (hot, common, ground(optional)) power system. The sensor reports Minimum RMS current, maximum RMS current, average RMS current, and amp hours to the iMonnit system. The iMonnit system is capable of generating watt hour or kilowatt hour readings as well.