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Understanding the Colors of Electrical Wires: The Basics

Man fixing wires

When trying to understand your home’s electrical system, you may encounter a tangle of colored wires. Here’s what those colors mean, and a few things to keep in mind when checking your wiring system. If your home is older or you’re having difficulty with your home’s wiring system, we recommend you utilize a certified electrician.

  • Black Wire: Hot
    First, you should always be aware of which wires may pose a safety hazard. Black, red, white with black or red tape will always indicate a hot wire. The term “hot” means these wires carry a live current from your electric panel to the destination. While white wiring is permitted— only when clearly marked with black or white tape—using any other color for a wire carrying current is strongly discouraged. This may pose a serious safety hazard that could result in death. Black or red wires always carry power from the service panel (breaker box) to your home’s devices.
  • Red Wire: Hot
    Red wires are usually used as a secondary hot wire. Red wires are also hot and should be clearly marked to avoid the dangers of electrocution. Red wires are commonly used when installing ceiling fans, where the light switch maybe.
  • Green Wire: Ground
    Green insulated wires are often used for grounding. Ground screws on electrical devices are often painted green, too. Never use a green wire for any purpose other than for grounding, as this may pose a serious threat of electrocution for you or a professional working on your home’s electrical system.
  • White or Gray Wires: Neutral
    White or gray indicates a neutral wire. The term neutral can be dangerously deceiving, as it appears to imply a non-electrified wire. However, neutral wires may carry power and can also pose a danger of electrocution if not handled properly, neutral wires carry power back to the service panel. Thus, both hot and neutral wires have the potential to shock and injure you if not handled properly.
  • Blue and Yellow Wires: Hot
    Blue and yellow wires are sometimes used as hot wires. Blue wires are commonly used for travelers in a three-way and four-way switch applications.

A multimeter will help you check and troubleshoot your home’s electrical wiring system. The multimeter can be used to check if there is an electric current flowing and how much. This can be especially useful if your home’s electrical system is old, outdated or if you are unsure which wires may be hot or not.

If you need help with your electrical wiring, call Mister Sparky® of San Antonio at (210) 899-2430 and we’ll send one of our professionals to assist you.