In a 240/120 Three-Phase Delta Four-Wire System, the ungrounded conductor with the higher voltage to ground must be identified with the color:

• A. Orange
• B. Red
• C. Yellow
• D. Blue

Answer: (A)

In a high-leg delta with a center-tapped transformer, one of the three phase conductors sits at a higher voltage to neutral (ground)—about 208 V—while the other two are 120 V to neutral. To prevent confusion and enhance safety, the high leg must be marked with orange insulation. This makes it immediately recognizable so it isn’t mistaken for a neutral in 120 V circuits. The other colors listed are used for the standard phase conductors and don’t indicate the high leg.