Which connection has three-phase leads and a neutral?

Which connection has three-phase leads and a neutral?

• A. Delta
• B. Open-delta
• C. Isolated
• D. Wye

Answer: (D)

Wye (star) connection has three phase leads plus a neutral because the three windings are joined at a common point, creating a neutral conductor that can carry current for line-to-neutral loads. This allows both the three phase voltages and a phase-to-neutral voltage to be supplied. In a Wye system, line-to-line voltage is the square root of three times the line-to-neutral voltage. Delta wiring, by contrast, forms a closed loop with no neutral, and open-delta or isolated configurations do not provide a neutral conductor for line-to-neutral loads.

Wye (star) connection has three phase leads plus a neutral because the three windings are joined at a common point, creating a neutral conductor that can carry current for line-to-neutral loads. This allows both the three phase voltages and a phase-to-neutral voltage to be supplied. In a Wye system, line-to-line voltage is the square root of three times the line-to-neutral voltage. Delta wiring, by contrast, forms a closed loop with no neutral, and open-delta or isolated configurations do not provide a neutral conductor for line-to-neutral loads.