Charge Up Your Safety: How to Apply Electrical Wiring Color Coding

Effective wire marking provides clear, instant hazard communication to workers and helps prevent injuries both routine work and maintenance.

Which standard should you use in your facility? 

Wire marking standards use color codes to identify specific wires. Not all electrical wiring color codes are the same.  It depends on your location, installation type, and voltage. 

When you document the color code that your facility follows, it makes work safer, and future maintenance easier.

1. For higher-voltage cases, it's important to have a documented wire labeling system.
2. Detailed labels can include information such as circuit identification, or the appropriate disconnection po1int for lockout/tagout.

U.S. Electrical Wiring Color Codes 

The U.S Electrical color code is typically used for power wires in “branch circuits.” Branch circuits are the wiring between the last protective device and the load.

120/208/240 Volt AC Wire Colors

These systems are common in home and office environments.

If the wiring system has one phase at a higher voltage than the others, use a “high leg” connection, and mark the wires with orange. (NEC article 110.15.)  

277/480 Volt AC Wire Colors 

  These higher-voltage systems are common in industrial motors and equipment. 

DC Power Wire Colors 

  Solar power systems and many battery systems use DC (direct current) power, rather than AC (alternating current). 

International Electrical Wiring Color Codes 

In some areas, a color code is specified by law; other areas rely on common practice. Different codes are popular in different areas. 

European (IEC) Wire Color Codes 

 Most European countries follow a wire color code established by the International Electrotechnical Commission (IEC) for AC branch circuits. This standard is covered by IEC 60445. 

Canadian Wire Color Codes for AC Power 

In Canada, wire color coding standards are set by the Canadian Electric Code (CEC). The color code for AC power wiring is similar to the code used in the United States: 

Data Wire Color Coding 

Telecommunications or computer network wiring applications use a different approach to identifying data cables via ANSI/TIA/EIA 606-A standard.  If a cable marker is blue, that indicates that it’s part of a specific subgroup of the local network. Printed text on the label identifies which workstation uses that cable, the port on the server it should be connected to, and when the cable was installed.

Wire markers should be visible during installation and normal maintenance of the wiring systems. The wire marking labels should use high-contrast and durable print. The markings should be durable enough to last as long as the wires themselves. 

Applying Color Codes to Electrical Wiring 

Most narrow wires will be color-coded by the manufacturer, using insulation of different colors. When wires are larger than #6 AWG, they are manufactured with black insulation. In these cases, color coding should be added during installation, via colored bands that wrap around the wire. 

The DuraLabel line of label printers offer a simple and reliable way to print long-lasting markers and wire tags. Self-laminating wire wraps and heat-shrink tubes are available to create clean, professional labels for your project.