Solid vs. Stranded, what’s the difference?
Solid conductor uses 1 solid wire per conductor, so in a 4 pair (8 conductor) roll, there would be a total of 8 solid wires. Stranded conductor uses multiple wires wrapped around each other in each conductor, so in a 4 pair (8 conductor) 7 strand roll, there would be a total of 56 wires.
Solid conductor is useful because it can be punched down onto wall jacks and since it is a single conductor, it seats properly in a insulation displacement connector. Solid is less useful when you are terminating RJ-45 connectors on it because most RJ-45 connectors use 2 prongs which penetrate the conductor. This is bad for solid because it has the tendency to break when it is penetrated. Using a 3 prong connector creates a good connection and doesn’t break the conductor, because the 3 prongs wrap around the conductor instead of penetrating it. We still recommend using stranded for patch cables, even if you have the 3 prong connectors because the most solid connection is made by penetrating multiple stranded connectors. Stranded is much less useful for punching down on wall jacks because the strands do not keep their perfect round shape when thrust into a insulation displacement connector. For the best results, use solid for wall jacks and patch panels. Use stranded for crimp-on connectors.