Solid core has a single solid copper strand inside of the insulated jacket making it quite rigid; when bent it will hold its shape (making this wire great for breadboarding). This rigidity does come at a cost: When bent too many times in the same place the wire could break internally – we don’t recommend using this wire in situations where it will be bending all the time. If you need something a little more flexible we do carry Stranded Core Wire which is much better in situations where movement or constant bending is a requirement.

18AWG (American Wire Gauge) is the internal size of the wire. Typically with 18AWG you can run ~7 amps a couple feet without too much voltage drop. For longer distances or higher current, a larger sized wire will be needed (smaller AWG number).