In a 3-phase wye system with a neutral, what is the typical line-to-neutral voltage in a 120/208 V system?

In a 3-phase wye system with a neutral, what is the typical line-to-neutral voltage in a 120/208 V system?

• A. 208 V
• B. 277 V
• C. 480 V
• D. 120 V

Answer: (D)

In a 3-phase wye system with a neutral, the line-to-neutral voltage is the voltage from any one line to the neutral point, while the voltage between two lines (line-to-line) is higher by a factor of √3. For a system labeled 120/208 V, the numbers mean V_LN is 120 V and V_LL is 208 V, because 120 × √3 ≈ 208. So the typical line-to-neutral voltage is 120 V. This naming also helps explain other common systems: 277 V would be the line-to-neutral in a 480Y/277 V setup (since 277 × √3 ≈ 480 V), whereas 480 V would be the line-to-line voltage in that same system.

In a 3-phase wye system with a neutral, the line-to-neutral voltage is the voltage from any one line to the neutral point, while the voltage between two lines (line-to-line) is higher by a factor of √3. For a system labeled 120/208 V, the numbers mean V_LN is 120 V and V_LL is 208 V, because 120 × √3 ≈ 208. So the typical line-to-neutral voltage is 120 V. This naming also helps explain other common systems: 277 V would be the line-to-neutral in a 480Y/277 V setup (since 277 × √3 ≈ 480 V), whereas 480 V would be the line-to-line voltage in that same system.