The EC-1V is a single-phase voltage data logger.  Setup the Logger using the Electrosoft software, then simply plug into a mains socket.
 
This logger can be installed by anyone when fitted with a plug!  Once you're set up, just turn on the voltage supply/socket and it'll start logging. The onboard indicator will flash Green when logging.
When the logger's finished recording (or you've captured enough data!) just disconnect from supply, hook it up to your PC and download the information.  Electrosoft will let you view the data immediately on-screen and save or export for later analysis.