Wiring 101: Identifying Wires

One of the most important things you should think about before taking on any residential electrical work is identifying all of the different cables and wires in your home. This may seem like a minor detail, but all it takes is one misidentified wire to result in injury, fire, or something even worse. Correct wire identification is just as important to the functionality of your electrical work as it is to the safety of you and your family. 

Welcome to Wiring 101, where we cover wiring basics. We give you the foundation to better understand and work with your home’s electrical wiring. Last time, we talked about basic safety practices and important warning signs. In this installment, we will look at the differences between cables and wires. We’ll also cover how to identify the different electrical cables and wires in your home. 

Cable vs. Wire

Outside of electrical work, the terms “cable” and “wire” are often used interchangeably. But there is actually a significant difference between the two. A wire is a thin, individual conductor. It can be bare or insulated depending on its specific application. Alternatively, a cable is an assembly of two or more wires wrapped in a single jacket. For this reason, cables are a bit thicker than wires and should be easily distinguishable. It’s vital to know whether you are dealing with cables or wires. You should also understand their functions. Fortunately, both cables and wires follow simple color-coding systems.

Color Coding: Cables

You probably noticed how the outer jackets of cables come in a range of colors. This, of course, is not for fashion but for function. The color of a cable’s outer jacket or sheath can tell you both the gauge of the wires inside and the amperage rating for the circuit.

WHITE 14 gauge wire 15A circuit
YELLOW 12 gauge wire 20A circuit
ORANGE 10 gauge wire 30A circuit
BLACK 8-6 gauge wire* 45-60A circuit*
GRAY underground feeder cable* *check sheath labeling for gauge and circuit specifics

Note that not all cables are color-coded. The practice of color-coding cable sheaths began in 2001 and remains voluntary. If your home has older wiring, you should not assume that the cables comply with this color-coding system.


Color Coding: Wires

This code is standard for all conductors. You may occasionally run into other wire colors, but these are the most common.

BLACK or RED HOT WIRE The hot wire is the one that carries the electrical current from the panel and to the outlet, switch, or appliance.
WHITE NEUTRAL WIRE The neutral wire completes the circuit by carrying the current back to the panel. Older buildings may not have one, but homes built after the 1980s should have neutral wires throughout.
BARE or GREEN GROUND WIRE The ground wire provides a path for faults to return to the panel. In the event of a ground fault, this blows the fuse to safely cut off the flow of electricity.

You can’t always count on these color-coding systems to be accurate 100% of the time. You will find that most modern electrical work will fit right in. But if you ever run into a cable or wire that you can’t identify, check the sheathing. Do some research you can to find out what it is. If all else fails, don’t be afraid to consult with a professional. There isn’t any room for guesswork when it comes to electrical wiring. ALWAYS identify a cable or wire before you even think about working on it.

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