# Wall Voltage in 3Phase

I have a relatively simple question on the grid voltage. When we say the voltage from the wall is 220 Vrms is that the line-line voltage or is that the phase voltage. ie are the two output lines from a socket both hot (in which case each line’s magnitude would be 220/sqrt(3) Vrms) or is one hot and the other neutral?

So, if the phase voltage is 230 volts (UK), the line (or phase to phase) voltage is $$\\sqrt3\$$ higher at 398 volts. If the phase voltage is 240 volts then the line voltage is 415 volts.