A split-phase system is a type of electrical power distribution commonly used in residential settings. It typically involves a transformer that provides two 120-volt lines and a neutral line, allowing for both 120-volt and 240-volt circuits. This setup is efficient for powering standard household appliances and lighting. In a split-phase system, the two 120-volt lines are 180 degrees out of phase with each other. This means that when one line is at its peak voltage, the other is at its lowest. This configuration allows for the use of 240-volt appliances, such as electric dryers and ovens, by combining the two 120-volt lines.