What is the color code for NM cable (Romex®) sheathing?
Sunday, July 8, 2018
The type of NM cable approved for indoor (dry location) use is NMB cable, and a color code for the plastic cable sheathing has been an industry standard since about 2001:
White - #14 AWG (rated for maximum 15 amps)
Yellow - #12 AWG (rated for maximum 20 amps)
Orange - #10 AWG (rated for maximum 30 amps)
Black - #8 and larger (higher amperage ratings - not shown above)
Gray - UF (Underground Feed) means cable rated for exterior use but color does not indicate wire size. Wire size printed along sheathing.
Color coding makes it easy to identify wire size in the cable at a glance but the National Electrical Code (NEC) does not require it. The NEC does, however, require that wire size be imprinted in the repeating data strip running along the sheathing.
The wires inside the sheathing are also color coded, as shown below. NM-cable for a 240-volt circuit will also have an additional hot wire that is red.
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