American wire gauge (AWG) question

[DA74254]

I'm afraid your question here is unaswerable..

The wiring is always measured by the "active" part, which would be the core.
The insulation varies in thickness quite massively, depending on brand and where it is manufactured.
Though, a rough guess will be that the 0,75mm2 or maybe the 0,5mm2 (AWG 18-20). The "standard" wires that I use in my DIY electronics (Arduino boards) is AWG 24 and the mentioned 0,75mm2/AWG 18 for battery/power leads.