Branch Circuits & WiringQuestion 237 of 521

Per 110.15, on a 4-wire delta-connected 120/240 V system, the high-leg (the conductor with the higher voltage to ground) must be identified by what color?

a.Orange
b.Blue
c.White
d.Green

Explanation

Section 110.15 requires the high-leg conductor (about 208 V to ground) to be durably marked orange or by other effective means. White is for the neutral and green for grounding, and blue is a normal ungrounded color that would not warn of the high leg.

Law Reference: 2023 NEC §110.15

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