I’m not an electrician, please consult with one if you’re unsure.
I think Shadow is right on both counts.
The wire is very old. Personally, I would rip it out, but that is a risk assessment you have to make.
A 240V circuit, in North America, gets there by having two hot wires one on each of the 120V circuts from the transformer in the street. So no neutral wire is needed to complete the circuit. If you want to think about electricity “flowing” it flows from one pole to the other (instead of to the neutral in a 120V circuit). The unshielded wire is your ground.
I’m not an electrician, please consult with one if you’re unsure.
I think Shadow is right on both counts.
The wire is very old. Personally, I would rip it out, but that is a risk assessment you have to make.
A 240V circuit, in North America, gets there by having two hot wires one on each of the 120V circuts from the transformer in the street. So no neutral wire is needed to complete the circuit. If you want to think about electricity “flowing” it flows from one pole to the other (instead of to the neutral in a 120V circuit). The unshielded wire is your ground.
This is a decent guide: https://www.thespruce.com/installing-a-240-volt-circuit-breaker-1824649
Please make sure you understand their point about what the main breaker does and does not disable.
Best of luck, looks like you’re tackling a tough but fun project.