How much current equipments are drawing from three phases
(combined or individual) is called three phase load and how much
supply we are getting from source is called three phase supply. Ex.
In INDIA single phase supply is 220 volt ac with neutral. So in
three phase supply all RYB phases should be 220 volts ac with
neutral individually. If we calculate with phase to phase than it
shoulb be 415 volts ac.