Power Wiring Color Codes
If you’ve got a basic home power wiring job on your hands, then chances are you’ve got a bunch of different colored wires staring you in the face. If you are unsure which wire should be attached where, then it may be helpful to review the common power wiring color codes so you can help ensure a successful and safe installation.
Black Power Wiring
For light switches and other power applications, black wire is typically used as the primary hot wire. This means that it is the wire that is directly connected to the 110-volt power source. This connection means that the black wire is always “hot,” or carrying an electrical charge. Due to this fact, extreme caution should be made to ensure that the electricity is turned off when working with black wires (actually, as a general rule, electricity should be turned off when working with any color of power wiring).
Red Power Wiring
Red power wiring is also used to indicate hot wires. However, in light switches and ceiling fans, the red wire is typically used as the switched leg hot wire. This means that it is connected to the on/off switch so that power only runs through it when the power switch is turned on. In international settings that utilize a 220-volt charge, the red wire may serve as the second primary hot wire (helping deliver additional voltage as an always-charged wire).
Blue and Yellow Power Wiring
Blue power wiring is common in three-way and four-way light switches. They are commonly used as the connecting wires that allow one light switch to “communicate” with another. This allows two switches to seamlessly control the same light source from two different locations. In some cases, blue wires may also be used as secondary switched legs in ceiling fans and other applications. Yellow wires may replace blue wires in any of these applications.
Green Power Wiring
A green power wire is the ground for an electrical appliance. It is attached to a screw or other device outside the circuit to help reduce the possibility of an electric shock. For some electrical appliances, a bare copper wire may be present in place of a green wire.
Power Wiring Considerations
These power wiring color codes are considered standards within the United States. However, they are by no means universal. As a result, one should always approach wiring projects with caution and the understanding that a previous electrician may have wired an appliance incorrectly. Additionally, color codes may vary by country. If you feel uncomfortable completing a specific wiring task, it is recommended you contact an experienced electrician.