Meter apparatus for determining parameters of an AC electric signal in first (L) and second (N) wires, the AC electric signal comprising an AC electric current ( I AC ) and an AC electric voltage ( V AC ), wherein the meter apparatus comprises: a measurement section configured for providing first ( V VS1 ) and second ( V VS2 ) measure signals each one indicative of the AC electric voltage ( V AC ) based on a first capacitive coupling ( C 1 ) with the first wire (L) and on a second capacitive coupling ( C 2 ) with the second wire (N), the first ( V VS1 ) and second ( V VS2 ) measure signals depending on capacitance values of the first ( C 1 ) and second ( C 2 ) capacitive couplings, first ( C 1 ) and second ( C 2 ) capacitive elements for performing said first and second capacitive couplings, and a control unit configured for: determining said capacitance values of the first ( C 1 ) and second ( C 2 ) capacitive couplings according to the first ( V VS1 ) and second ( V VS2 ) measure signals, and determining the amplitude of the AC electric voltage ( V AC ) according to the first ( V VS1 ) or second ( V VS2 ) measure signal, and to the capacitance values of the first ( C 1 ) and second ( C 2 ) capacitive couplings, wherein said measurement section further comprises first ( C 3 ) and second ( C 4 ) input capacitive elements electrically coupleable to the first ( C 1 ) and second ( C 2 ) capacitive elements, respectively, the first ( C 1 ) and second ( C 2 ) capacitive elements and, respectively, the first ( C 3 ) and second ( C 4 ) input capacitive elements defining, when coupled to each other, an impedance voltage divider ( C 1 ,C 3 ; C 2 ,C 4 ) for providing said first measure signal ( V VS1 ) from said AC electric voltage ( V AC ), the first measure signal ( V VS1 ) being in phase with respect to said AC electric voltage ( V AC ) . a measurement section configured for providing first ( V VS1 ) and second ( V VS2 ) measure signals each one indicative of the AC electric voltage ( V AC ) based on a first capacitive coupling ( C 1 ) with the first wire (L) and on a second capacitive coupling ( C 2 ) with the second wire (N), the first ( V VS1 ) and second ( V VS2 ) measure signals depending on capacitance values of the first ( C 1 ) and second ( C 2 ) capacitive couplings, first ( C 1 ) and second ( C 2 ) capacitive elements for performing said first and second capacitive couplings, and a control unit configured for: determining said capacitance values of the first ( C 1 ) and second ( C 2 ) capacitive couplings according to the first ( V VS1 ) and second ( V VS2 ) measure signals, and determining the amplitude of the AC electric voltage ( V AC ) according to the first ( V VS1 ) or second ( V VS2 ) measure signal, and to the capacitance values of the first ( C 1 ) and second ( C 2 ) capacitive couplings, determining said capacitance values of the first ( C 1 ) and second ( C 2 ) capacitive couplings according to the first ( V VS1 ) and second ( V VS2 ) measure signals, and determining the amplitude of the AC electric voltage ( V AC ) according to the first ( V VS1 ) or second ( V VS2 ) measure signal, and to the capacitance values of the first ( C 1 ) and second ( C 2 ) capacitive couplings, <EOS>