In a 480Y/277 V system, what is the line-to-neutral voltage?

• A. 277 V
• B. 600 V
• C. 480 V
• D. 208 V

Answer: (B)

In a three-phase wye system, the line-to-line voltage is sqrt(3) times the line-to-neutral voltage. So the line-to-neutral voltage = line-to-line voltage divided by sqrt(3).

For a 480Y/277 V system, the line-to-line voltage is 480 V. Dividing by sqrt(3) (approximately 1.732) gives 480 / 1.732 ≈ 277 V. Therefore, the line-to-neutral voltage is about 277 V.

This is why 277 V is the correct line-to-neutral value for this system, while 600 V or 208 V don’t apply here.