You have to buy the Aeotec that corresponds to your grid system. In Norway these are typically TN (400V) or IT(230V), and you will need two different products for 3 phase measuring on the different grid systems depending on which you have. 3phase3clamps for TN and 3phase2clamps for IT.
But still it calculates kWh 3 times higher then it really is, so I created a virtual power meter to correct this value. See attached pic for my solution. 
