Which statement best describes a split-phase system?

• A. Three-phase delta with 480 V.
• B. Single phase 120 V.
• C. Two 120 V legs that are 180 degrees out of phase, producing 240 V between them.
• D. Two 208 V lines in a wye system.

Answer: (C)

Split-phase means you have two hot conductors that come from a center-tapped transformer and are 180 degrees out of phase. Each leg is 120 V to neutral, and the voltage between the two hot legs is 240 V. That setup is exactly described by two 120 V legs that are opposite in phase, producing 240 V between them. It’s the standard residential service in the United States, giving both 120 V outlets and 240 V appliances by using the neutral as the midpoint.

The other descriptions point to different systems: a three-phase delta with 480 V is a multi-phase Power system, not split-phase. Single-phase 120 V lacks the second hot leg to create 240 V between lines. A 208 V line system in a wye arrangement provides 208 V between lines and 120 V line-to-neutral, with three phases 120 degrees apart, not two opposite phases.