Remove the plastic outer cover of a non-metallic electrical cable and what you’ll find inside is a colorful assortment of smaller, interwoven wires.
But those bright wires aren’t just for show: They’re color-coded. And knowing what each of those colors means can help you stay safe when you’re around electricity.
With that in mind, let’s discuss the color-coded wires you’re most likely to encounter:
Wires that carry electricity from the service panel to a destination, such as your lamp or toaster, are said to be “hot.” In most cases, these wires are wrapped in black insulation, but red insulation may also be used (for example, as the second wire in a 240-volt installation).
It’s also acceptable to use white insulation for hot wires. However, such wires should be looped in black or red electrical tape to signify their “hot” status. (Blue and yellow insulation may be used on hot wires in an electrical conduit. However, these colors are rarely found in non-metallic electrical cables.)
According to The National Electrical Code (NEC), white and gray insulation must be used for all neutral electrical wires. But remember, white wires sometimes double as hot wires, so always look for those tell-tale loops of black or red electrical tape. And keep in mind that this tape can get separated from the wire — if you see any loose tape in the box, proceed with caution.
The NEC requires that bare copper or green wires must be used to ground all electrical devices. Ground wires connect electrical devices to metal appliance frames or housings to provide a safe path for electricity to travel in case of a fault. While most ground wires are bare copper, green insulation is also designated specifically for grounding and should not be used for any other purpose.
Remember, safety first. If you’re not certain about the function of a specific electrical wire, get professional help. And if you have any other questions, please get in touch.