Cables: all cables consist of three types of wires. The first is to carry current, the second is to make the circuit complete, and the third is the grounding wire. These wires have different specification numbers, sizes and codes. The codes marked on them tell us their insulation and electrical capabilities. If the cable you use is marked "G", use a ground wire. One common example of this type of cable is the use 12 – 3/g cable. Cables usually have nm-b, BX and uf-b sheaths. They can be roughly divided into two types according to their conductors. The first is a two core cable, and the second is a three core cableNowadays, like everything else, wires and cables can also be purchased online. Many suppliers on the Internet are committed to providing all types of wires and electrical equipment online at a cost-effective price.