Romex is a brand name that became the everyday word for NM-B cable: two or three insulated conductors plus a bare ground in a PVC jacket. The jacket color is coded to conductor size: white for 14 AWG, yellow for 12, orange for 10, black for 8 and 6. It is stapled to studs and joists in houses and small buildings and is not allowed in many commercial occupancies or in wet locations. Canadian electricians call the equivalent Loomex or NMD90.
Kitchen counters get twenty-amp circuits, so pull yellow Romex, twelve-two, and leave a good tail in every box.
Twelve-two means two 12 AWG insulated conductors plus a bare ground; the ground is never counted in the name.
Also heard as
- NM
- NM-B
- rope
- Loomex
Related terms
BX
Trade name used for armored cable: insulated conductors inside a spiral metal jacket.
MC cable
Metal-clad cable: insulated conductors, including a green ground, inside interlocked aluminium or steel armor.
Make up
To splice, pigtail and fold the wires in a box so it is ready for a device or cover.
Home run
Part of a circuit running from the first box back to the panel, or the arrow on a drawing that shows it.