Bare copper or green wires are used as ground wires.
White or gray indicates neutral wires.
What Are Wire Color Code Standards?
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Cable Sheathing
The sheathing is a tough outer coat that binds the inner wires together.
The color of the sheathing indicates thegauges (or thicknesses) of the wiresinside.
Printednumbers and words on the sheathingtell you the number and the gauges of the wires within the sheathing.
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White or gray must be used for neutral conductors.
Bare copper or green wires must be used as ground wires.
Beyond that are general, industry-accepted rules about wire color codes that indicate their purpose.
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This is commonly found in most standard household circuits.
Red Wires: Hot
Red insulation is used to designate hot wires.
Red wires are sometimes used as the second hot wire in 240-volt installations.
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The other common use for the red wire is switching.
Sometimes other colors are used, as well.
All electrical devices must be grounded.
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Metal electrical boxes also need ground connection because they are made of a conductive material.
Plastic boxes are non-conductive and do not need to be grounded.
Green Wires: Ground
Green plastic insulation is sometimes used to indicate ground wires.
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Ground screws on electrical devices are often painted green, too.
Never use a green wire for any purpose other than for grounding.
White or Gray Wires: Neutral
White or gray wire insulation indicates a neutral wire.
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When examining a white or gray wire, make certain that it has not been wrapped in electrical tape.
This would indicate a hot wire.Older wires sometimes may lose their electrical tape wrapping.
The term neutral can be dangerously deceiving as it appears to imply a non-electrified wire.
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It is important to note that neutral wires may also be carrying power and can shock you.
Thus, both hot and neutral wires have the potential to shock and injure you.
Rarely are blue and yellow wires found within NM cable sheathing.
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Blue wires are commonly used for travelers in three-way and four-way switch applications.
Using the wrong color codes will make you less safe because you are at a greater risk of shock.
Your home is less safe, too, because improperly connected wires may cause a fire.
Each wire’s purpose is labeled for you.
Electrical Wiring Coding System: What you gotta Know.SummitCollege.
