Homeowner Electrical Cable Basics | The Family Handyman
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Not All Cable Is Color-Coded
Cable-sheath color coding started in 2001 and is still voluntary. If you have older wiring, don’t assume it complies with the current color coding. However, most manufacturers now follow the standard color code.
Wiring problems and mistakes are all too common, and if left uncorrected have the potential to cause short circuits, shocks and even fires. Planning to buy smart devices? Here’s what you need to know about smart home wiring.
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Wire Color Coding
This code is standard for all conductors. The colors you’re most likely to find in your home are the following:
BLACK (OR RED) = HOT. Hot wires carry current from the panel to the device, which could be a switch, receptacle, light fixture or appliance. There are other colors for hot wires, but they’re much less common.
WHITE = NEUTRAL. Neutral wires carry the current back to the panel, completing the circuit.
BARE (OR GREEN) = GROUND. In the event of a ground fault, the ground wire provides a path for the fault current to return to the panel, opening the breaker or blowing the fuse and cutting off the flow of electricity.
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NM-B – Nonmetallic Cable
This is the most common type of electrical cable in homes built since the mid-’60s. “Nonmetallic” simply means that the outer jacket is not metal. It’s often referred to as Romex, which is a brand name. Typically, NM-B cable has either two conductors and a ground, or three conductors and a ground. The conductors are individually insulated, wrapped in paper and sheathed in plastic. Ground wires are either bare copper or insulated in green.
14-2 Used for general lighting and receptacle circuits. 15-amp circuit maximum.
14-3 Used for three-way switches and split receptacle circuits. 15-amp circuit maximum.
12-2 Used for 20-amp kitchen, bathroom, laundry and garage receptacles; 230-volt heating circuits up to 3,700 watts; and 115-volt circuits up to 1,800 watts. Can be used anywhere in place of 14-2.
12-3 Same uses as 12-2, with the addition of three-way switches and split receptacle circuits.
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