Stranded conductor cables are very commonly used today. Inside the twisted pairs of stranded cables, each individual conductor is made up of a bundle of smaller-gauge wire strands. Generally six or seven strands are used to surround a single wire in the center. The outer strands are wrapped helically around the central wires. The stranded wires form a conductor with the similar diameter to a solid cable. But the conducting area is smaller than that of a solid cable due to the smaller diameters of each individual conducting wire strand.
The stranding structure makes stranded cables flexible. Even though the cables are bent, cables can’t be easily harmed since each strand is independent of the entire strand. Let’s see how this works. When cables are bent, all individual strands are pulled towards the center. The total stresses are distributed to all the strands to minimize the stresses on the center conductor. As a result, cable conductors can get more supports if there are more twists to the wire strands.
The conductors of stranded cables used for networking and Ethernet applications are made of bare or tin-coated copper wires. Tin-coated conductors can protect the conducting surfaces from oxidation and keep individual wire strands from fraying. That’s because of production process of tin-coated conductors. All the individual wire strands have to be dipped in a bath of molten tin before they are assembled into a single conductor.
But stranded conductor cables can cause higher insertion loss for their smaller conducting diameters especially for long distance transmission (of course the distance has limits for both solid and stranded conductor cables). Stranded conductor cables have high DC resistance which causes signals dissipation as increased heat during long distance transmission. So stranded conductor cables are not as good as solid cables for long distance runs. Another shortage of stranded cables is that they are more expensive than solid conductor cables for the equivalent length since they are expensive to manufacture.