Electricity powers the world. It lights up, turns on and charges nearly everything we touch, all with the flick of a switch. But behind switch plates and outlets lies a colorful, spaghetti-like network of wires: red, black, yellow, green — each designed to connect, and keep us safe.

Whether you install, repair or upgrade wires, you may have noticed, no two wiring systems are exactly the same. But most do share at least one thing in common: a way to identify each wire. And that way is with color.

Simply put, color makes it easier to work with wires. Just ask those who come in frequent contact with wires, mainly:

• Electricians

• Electrical engineers

• Contractors

• Technicians

• Homeowners

Instead of wondering … Is this wire hot? Neutral? For grounding? A quick look at a wire’s color can reveal its role in powering an appliance or circuit. It’s simple. It’s safe. And, it’s designed to take the guesswork out of electrical work.

But it wasn’t always this way.

A brief history of wiring color codes

It took until 1928 for wire color coding to make its debut. The National Electrical Code® (NEC) was the first to reference it, and today continues to set the standards for the electrical industry. Following a uniform color code makes it easier to assess electrical wiring, and ensure safety among licensed professionals and homeowners alike.

6 Benefits of using color-coded wires

Color has many benefits, especially when used with electrical wires.

1. Color grabs our attention

It’s no mystery, color gets our attention. When compared to non-colored items, it’s the colored ones that command more of our visual attention. For electricians, wire colors indicate how power moves within circuits.

1. Color increases safety

Color alerts us to danger. In the case of electricity, recognizing a red electrical wire (hot wire) could mean lowering the risk of electrical shocks, burns, electrocution and fires. If a body encounters a high-magnitude electrical surge, it could take years to recover.

Prevention, therefore, is key when it comes to electrical safety. And color can help reduce the overall risks.

1. Color creates better memory performance

We remember better when colors are used compared to when they’re not. That’s because colors play an essential role in keeping information in the memory system. Since electrical wires are colored, it’s easier to understand their purpose within a network.

2. Color reduces downtime

Whether in a commercial, residential or industrial setting, incorrectly identifying wires could lead to accidental outages, causing unexpected downtime for both residents and workers. Colored wires prevent outages by creating a reliable system of identification.

3. Color can cut costs

Repairs are expensive when a wrong wire is cut. Power outages can cause missed transactions and lost sales. Using colored wires could end up saving businesses money in the long run.

4. Color can decrease the risk of property damage

Electrical incidences such as overheated wires or fires can cause significant property damage. Using colored wires can lower this risk by ensuring circuits are connected properly.

The NEC wire color coding standards

Though there are international wire color codes, the U.S. follows the National Electrical Code® (NEC). The code is identified as NFPA 70® because the NEC is sponsored by the National Fire Protection Association. Though not a federal law (states can choose to adopt it), it is approved by the American National Standards Institute (ANSI). Every three years, the NEC reviews, amends and adopts the latest code. The current NEC was last updated in 2020.

Why follow the NEC?

Laws and safety

Most businesses adhere to the NEC because it’s state law. Others follow it because it’s considered a best practice for improving workplace safety. Injuries and incidents may be costly, so wiring, regardless of its scope or scale, should be taken seriously.

Communication and troubleshooting

In addition to making new installations safer, following the NEC provides communication for future projects. Workers, maintenance crews and contractors (who frequently update wires) have come to rely on this color-coding system. It makes troubleshooting easier and faster.

Education and consistency

If you’d like to become a licensed electrician, your training will require a solid understanding of the NEC. This ensures consistency, whether on new construction or if updating wiring in a pre-existing building.

Cost

There is no extra cost for following the wire coding standards. The thin, PVC sheath that wraps each wire costs the same for each color.

These benefits encourage businesses to accept practices that have been adopted in their area.

Electrical Wiring Color Codes

The wire color coding guidance provided below applies to electrical wiring in the United States. Though there may be exceptions (e.g., old wiring, regional differences, the wrong color wire was installed), this section can be used as a general overview for electrical wire color codes.

In addition to identifying a wire by its color, always check to see that wires are de-energized. Of major concern are hot wires, which carry live electrical current from the electrical panel to outlets and light fixtures.

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3-Phase Wire Color Codes

Whether adding a home appliance or industrial machinery, you’ll need to know these electrical wiring color codes. In the U.S., these color-coded wires carry power from a circuit breaker to a device.

AC Power

Alternating current (AC) is the power that comes out of outlets in homes and businesses.

Homes and offices: 120, 208 or 240 Volts

• Phase 1 – Black wire

• Phase 2 – Red wire

• Phase 3 – Blue wire

• Neutral – White wire

• Ground – Green, Green with a Yellow Stripe, or Bare Wire

Industrial equipment: 277 or 480 Volts

• Phase 1 – Brown wire

• Phase 2 – Orange wire

• Phase 3 – Yellow wire

• Neutral – Gray wire

• Ground – Green, green with yellow stripe, or bare wire

When powering higher-voltage devices, be sure you are labeling wires and cables accurately and add safety signs, where needed. This identification can be used during a lockout tagout, should the equipment need to be de-energized.

DC Power

Direct current (DC) is used in cell phones, flashlights, cars and solar panels. It can also be used for industrial processes and to transmit large amounts of power from remote locations.

• Positive – red wire

• Negative – black wire

• Ground – white or gray wire

How Brady can help

Just like no two electrical projects are the same, you’ll find Brady support comes in different shapes and sizes. They offer industrial label printers, cable labels, wire markers, heat shrink sleeves, electrical safety signs and software — effective and easy ways to communicate vital information, and stay safe.

In addition to color ID, Brady offers high-performing wire and cable labeling materials that can keep you compliant. Some are self-extinguishing, while others resist chemicals, oil and moisture. In flags, tags, self-laminating, rotating and wraparounds, Brady wire markers and cable labels are durable and designed to stay visible in any environment.

Brady also makes pre-printed and custom tags and safety signs. These can also be created with on-demand printers. Informing others about potential electrical hazards (conduit labels, voltage markers, electrical panels, arc flash, lockout tagout) can reduce the threat of injury. Whether posting indoors or outdoors, just know the text, graphics and color will hold up to the elements, abrasion and repeated spills and cleanings.

If you’re looking for additional solutions, Brady is here to help. Let them know a little more about your application and they'll gladly recommend products and services that can improve your work experience.

Previously Featured on Brady's website.

References

1^ Hospital News. (n.d.) The invisible injuries of electrical shock and getting patients ‘Back on Track’.