• Grounding conductor (“protective earth”/“ground”): wires must be bare, green, or green/yellow striped
• Grounded conductor (“neutral”): wires must be white or gray
• Orange, when used in a 3-phase 4 wire delta configuration supplying 120/240, shall designate the “wild” leg with 208v to neutral.
  • Orange is the only ungrounded conductor specified by the NEC. In a 120/240 center-tapped neutral delta configuration, the two end phases on the center-tapped winding provide 120 volts to neutral, but on the wild leg you will find nearly 208 volts to the neutral. If you see an orange wire in a panel, alarm bells should go off: You don’t want to wire a 120 VAC circuit across the wild 208 volt phase.

• Grounding conductor (“protective earth”/“ground”): wires must be bare, or green/yellow striped
• Grounded conductor (“neutral”): blue.
• PEN (Protective Earth/Neutral, combined) conductor, when insulated, shall be marked by one of the following methods:
  • Green-and-yellow throughout its length with, in addition, light blue markings at the terminations, or
  • Light blue throughout its length with, in addition, green-and-yellow markings at the terminations

The following are suggested wire colors when your local electrical code does not designate wire colors. Where your local electrical code conflicts with this standard, you must follow your local code requirements.

• black, red and white

• black, red, blue and white

• black, orange, blue and white

• brown, violet, yellow and gray

• brown and white
• brown and blue¹⁾

• brown, purple, yellow, gray
• brown, purple, yellow, blue

• http://en.wikipedia.org/wiki/IEC_60446
• https://en.wikipedia.org/wiki/Electrical_wiring#Color_code
• http://www.allaboutcircuits.com/vol_5/chpt_2/2.html
• Comparison of NFPA/NEC & IEC Wiring Standards - Free (login)
• NFPA 70 - National Electrical Code (NEC) - Free (login)
  • http://www.nfpa.org/freeaccess