Angus80808, You will need to reconfigure one of the existing 120V dedicated branch circuits to a 250V dedicated branch circuit. At the electrical panel the 250V branch circuit must be connected to a 2 pole breaker. If the wire is #12 awg and the receptacle is a 20 amp then the breaker must be a 2 pole 20 amp breaker.
As in regards to phasing the power that feeds your home is fed from a split phase secondary winding of the power company's utility transformer. Single phase, only one phase. Two hot ungrounded conductors with a center tapped grounded conductor, the neutral.
As in regards to phasing the power that feeds your home is fed from a split phase secondary winding of the power company's utility transformer. Single phase, only one phase. Two hot ungrounded conductors with a center tapped grounded conductor, the neutral.