What is the standard voltage configuration for most US residential services?

What is the standard voltage configuration for most US residential services?

• A. 277/480 V three-phase service.
• B. 208 V single-phase service.
• C. 600 V delta service.
• D. 120/240 V split-phase service.

Answer: (D)

Most US homes use a split-phase system: a center-tapped transformer provides two hot conductors that are 180 degrees out of phase, plus a neutral. Each hot to neutral delivers about 120 V, and the two hot conductors together supply about 240 V between them. This setup supports standard 120 V outlets throughout the house and 240 V for large appliances like dryers or ranges from a single service entrance. The other configurations mentioned (277/480 V three-phase, 208 V single-phase, or 600 V delta) are used in commercial, multifamily, or industrial settings, not typical residential homes.

Most US homes use a split-phase system: a center-tapped transformer provides two hot conductors that are 180 degrees out of phase, plus a neutral. Each hot to neutral delivers about 120 V, and the two hot conductors together supply about 240 V between them. This setup supports standard 120 V outlets throughout the house and 240 V for large appliances like dryers or ranges from a single service entrance. The other configurations mentioned (277/480 V three-phase, 208 V single-phase, or 600 V delta) are used in commercial, multifamily, or industrial settings, not typical residential homes.