Final answer:
The white wire in a 120V wiring system is generally recognized as the neutral wire, which is connected to the earth to maintain a potential of zero volts for safety. The color-coding of electrical insulation varies by region, making it important to consult local codes, but generally, the neutral wire is white or sometimes blue or black in some areas.
Step-by-step explanation:
In a 120V electrical wiring system, the white wire typically represents the neutral wire. It is connected to the earth at the power source and the user location, which forces it to be at zero volts relative to the earth. This design makes the wire safe to touch, even if the insulation is missing.
The neutral wire serves as the return path for the current to complete the electrical circuit. To ensure safety and proper functioning, the neutral wire's connections offer an alternative return path for the current through the earth or ground. Wire color-coding may vary by region, and it's essential to be aware of local codes. However, the neutral wire is commonly identified by its white insulation in many areas, although it can also be blue or black in some places. Ground wires are often green, yellow, or just a bare wire.
It should be noted that in regions where different color coding is used, it is imperative to verify the local code to avoid confusion between the live/hot and neutral wires, as this can lead to safety hazards. In the United States, standard practices designate the white wire for neutral, the black or red wire for live/hot, and the green wire or bare copper for ground.