Which voltage configuration represents a three-phase wye system with 120 V line-to-neutral?

Which voltage configuration represents a three-phase wye system with 120 V line-to-neutral?

• A. 208Y/120 V.
• B. 120/240 V.
• C. 480Y/277 V.
• D. 600Y/347 V.

Answer: (A)

In a three-phase wye system, the line-to-neutral voltage is the phase voltage, and the line-to-line voltage is √3 times that value. If the line-to-neutral is 120 V, the line-to-line voltage should be about 208 V (120 × √3 ≈ 208). So 208Y/120 V represents a three-phase wye setup with 120 V to neutral and 208 V between any two lines, matching the required configuration. The other options either show different line-to-neutral voltages (277 V or 347 V) or describe a split-phase service (120/240 V) that isn’t a true three-phase wye.

In a three-phase wye system, the line-to-neutral voltage is the phase voltage, and the line-to-line voltage is √3 times that value. If the line-to-neutral is 120 V, the line-to-line voltage should be about 208 V (120 × √3 ≈ 208).

So 208Y/120 V represents a three-phase wye setup with 120 V to neutral and 208 V between any two lines, matching the required configuration. The other options either show different line-to-neutral voltages (277 V or 347 V) or describe a split-phase service (120/240 V) that isn’t a true three-phase wye.