Your Guide to Electrical Wire Color Codes

Before you attempt a DIY electrical project, make sure you know what you’re getting into. If you’re unfamiliar with the standard electrical wire color codes, attempting a repair can lead to a confusing tangle of different cable colors. Our wire color guide shows you what to look for when finding a specific wire.

What Color Is the Ground Wire?

The protected ground wire color must be bare metal, green, or green with a yellow stripe. In some direct current (DC) systems, the protected ground may also be white or gray, as these systems don’t always have a neutral wire.

Grounding wires help prevent electrical shock and system overload by redirecting excess power into the ground to dissipate. Usually, ground wires only come into play when the neutral wire fails to keep the circuit balanced. This can be due to a power surge, electrical energy overload, or damage to the neutral wire.

What Color is the Neutral Wire?

Neutral wires must be white or gray colored, as mandated by the US National Electrical Code.

Neutral wires carry electrical current from the device back to the electrical box, keeping the electrical circuit in equilibrium. They have an electrical charge and can still shock you if you touch a non-insulated wire.

What Color Wire Is the Common Wire?

The common wire is another name for the neutral wire used in your heating system. In the US, the common wire should be white or sometimes gray. However, some homes have incorrectly colored cables. A professional electrician can test your wires to find the common wire, or you can use a multimeter.

To test for the common wire:

  1. Turn off your home power at your breaker box.

  2. Cap off the wires you don’t need to test, taking special care with wires you suspect are live.

  3. Turn the power back on.

  4. Set your multimeter voltage to the highest DC setting available.

  5. Test the wire by connecting it to the red prongs of the multimeter. A multimeter reading means the wire is hot, and you must take extra precautions not to touch this live wire. No reading on the multimeter means you’ve found the common wire.

  6. Turn the power off, reconnect all your wires, and turn the power back on.

What Color Is the Hot Wire?

Hot wires can be any color other than those used for grounding and neutral wires. However, many electricians follow similar coloring systems, making things easy to follow. Hot wires carry electricity from the source to the device it’s powering.

Be extra cautious when handling hot wires, as they carry an electrical charge. Always turn off the power to your home before handling wires you suspect are hot.

What Color Is the Negative Wire?

The first or negative hot wire is almost always black. However, some people repurpose a white neutral wire as a hot wire, indicated with a wrapping of black electrical tape at one end.

What Color Is the Positive Wire?

The second hot wire, a positive wire, is usually red. If you find a white neutral wrapped in red electrical tape, it indicates a neutral wire repurposed as a positive wire. If you have a phase 3 circuit, there may be a third hot wire, usually in blue.

Leave Complex Wiring to the Professionals

Even if you know these standard wire colors inside and out, working on electrical systems is complicated and often dangerous. Never handle your home’s electrical wiring if you don’t know what you’re doing. Always entrust complex electrical problems to professionals, like Mister Sparky of Atlanta. We handle wiring problems large and small, and we can ensure all your wiring is up to code. Call (770) 824-9592 to schedule service or book an appointment online.