In a 277/480-volt, 3Ø, 4-wire system, the line-to-line voltage is 480 V.

In a 277/480-volt, 3Ø, 4-wire system, the line-to-line voltage is 480 V.

• A. 277
• B. 120
• C. 480
• D. 240

Answer: (C)

In a three-phase system with a wye connection and a four-wire setup, the line-to-line voltage is √3 times the line-to-neutral voltage. For a 277/480 V system, the line-to-neutral voltage is 277 V, so the line-to-line voltage is 277 × √3 ≈ 480 V. The presence of the neutral wire supports 277 V loads from each line to neutral. The other voltages listed correspond to different configurations and aren’t the line-to-line value for this system.

In a three-phase system with a wye connection and a four-wire setup, the line-to-line voltage is √3 times the line-to-neutral voltage. For a 277/480 V system, the line-to-neutral voltage is 277 V, so the line-to-line voltage is 277 × √3 ≈ 480 V. The presence of the neutral wire supports 277 V loads from each line to neutral. The other voltages listed correspond to different configurations and aren’t the line-to-line value for this system.