They're called enameled cables, they've got a thin layer of insulation which prevents them from rusting or shorting.
To add, enameled wires are also used in motor windings and old CRT monitors (deflector windings). The easiest way to identify it is to scratch with a knife or burn a small portion of the wire to see if the enamel separates.
What does it look like when the enamal seperates vs a non-enameled wire?
Slightly brighter and shinier. The enamel gives it a slightly darker matte finish. More importantly though, the peeled/burned enamel looks different from copper.
They're called enameled cables, they've got a thin layer of insulation which prevents them from rusting or shorting.
To add, enameled wires are also used in motor windings and old CRT monitors (deflector windings). The easiest way to identify it is to scratch with a knife or burn a small portion of the wire to see if the enamel separates.
What does it look like when the enamal seperates vs a non-enameled wire?
Slightly brighter and shinier. The enamel gives it a slightly darker matte finish. More importantly though, the peeled/burned enamel looks different from copper.