NK Technologies APN Series Power Monitor measures three phases of current and voltage and computes fourteen values necessary to track power usage. The monitor uses current transformers to measure the amperes. The line voltage connects directly to the transducer, up to 600 VAC. The result is 14 data points in the RS485 Modbus RTU format. There is also a pulse contact which opens and closes as watt hours are accumulated. The APN can be configured to accept five amp secondary current transformers or the safer ProteCT™ low voltage output CTs. Either type will produce an accurate set of data to help you save energy and avoid utility surcharges.