US AC Power Circuit Wiring Color Codes are specific colors assigned to different wires in AC electrical systems, practiced primarily in the United States. These color codes guide electricians, technicians, and engineers in identifying various AC power circuit wires for troubleshooting, maintenance, and documentation purposes. The US AC Power Circuit Wiring Color Code Standards are established by the National Electrical Code (NEC). It insists on wire color standards for Residential and Commercial wiring.

120/240 V AC Circuit Wiring (Residential Wiring)

It presents the wiring color code standards for hot (Phase), neutral, and ground wires applicable to home and office applications.

In a three-phase wiring system, Hot wires are denoted by Black, Red, and Blue colored wires. Neutral wires are given a White color and Ground wires are indicated by Green, Green with a Yellow stripe, or as a bare wire. In high-leg connections where the voltage of one phase exceeds the others, Orange colored wires denote the high-leg. In a single-phase wiring system, a Hot wire is denoted by Black color and an optional Red Color for a second Hot wire used generally for split-phase systems.

277 V or 480 V AC Circuit Wiring (Commercial Wiring)

It offers the wiring color code standards for Hot (Phase), Neutral, and Ground wires applicable for industrial and high-power applications.

In three-phase systems, Brown, Orange, and Yellow colored wires denote Hot wires. Neutral wires are given a Grey color and Ground wires are indicated by Green, Green with a Yellow stripe, or as a bare wire. Single Phase system follows Black color for the hot wire and red color for an optional second hot wire.