When a voltage measuring device is connected to AC mains, the meter shows the steady input voltage of 22O V this means

The voltmeter in AC circuit reads value $\sqrt{<{\mathrm{v}}^2>}$ and meter is calibrated to rms value $\sqrt{<{\mathrm{v}}^2>}$ which is multiplied by $\sqrt{2}$ to get V_peak . In other words, voltmeter connected to the AC main read root mean square value  $\sqrt{<{\mathrm{v}}^2>}$.