Compare all Specifications 12/2 x 250 ft. Solid CU MC (Metal Clad) Armorlite Cable 12/2 x 250 ft. Solid CU BX/AC (AL Armored Cable) Armorlite Cable $107.30 $122.11 (154) (4) Conductor Gauge Conductor Gauge 12 Total Wire Length (ft.) 250 Total Wire Length (ft.) 250 Click to see full answer. Likewise, what is a 12 2 wire?”12-2″ means 12 gauge, two insulated current carrying wires, plus a bare ground. 12-2 wire usually has a black, white and bare ground wire. Sometimes the white is red instead for 220V circuits without neutral. In the latter case, the sheath is usually red too.Subsequently, question is, what do the numbers on Romex mean? Romex is used for most lighting and outlet circuits in your home. Romex will be labeled with “12-2” or “12-3”. The first number indicates the gauge of the wire. You choices are typically 10, 12, or 14 gauge. The second number indicates the number of conductors. Considering this, what is MC cable? Metal-clad cable comes in several varieties, but the type you’ll find at most home centers is three insulated wires (two circuit conductors and a green equipment grounding conductor) protected by a flexible armor usually made from aluminum. MC cable is identified by the gauge of the wire, not the diameter of the armor.What is the difference between 12 2 and 12 3 Romex?Bottom line is that you use 12/2 when you need two conductors plus ground, and 12/3 when you need three conductors plus ground.