Copper wire is a narrow strip of reddish, metallic material. When placed, it will cover two or more halves of a block space's vertical and/or horizontal centers.
Where Found
Copper wire is created on one of the two types of metalwork benches. Five pieces of wire are obtained from one copper ingot.
Prior to version 1.5.1, a non-electric metalwork bench could be used to make ten elevator shafts for one block of steel and ten copper wires, which was more steel-efficient than an electric metalwork bench.
Uses
The only way to get electricity across gaps between crafting surfaces is to place copper wire or a conducting block in an unbroken series of vertically and/or horizontally adjacent spaces between them. Wire can be placed in any space with a back wall or adjacent solid block, crafting surface, or wire. Starting in version 1.5 it may also be placed on a solid block, allowing electricity to be conducted through it, as long as the block isn't an ore block.
It is also possible to use copper wire as a decoration.