Internal Wire Gauge?

Suitable for Framing ...

"  Electricity seems to be a fickle beast and simply loves to flow. It doesn't seem to care too much about which route it has to take as long as there is a route. "

I don't know about other folks, but I try to avoid accidentally buying 300V wiring for tube amp builds. The wire rating I cited above is used by transformer manufacturers in their mains and output transformers. UL 1015 is not shielded wire; it is a PVC jacketed hookup wire with a rating of 600V and is specifically designed to work in appliances, including tube amplifiers.

And don't forget to check the voltage ratings of the resistors. Some of those boutique brands (including Vishay RN60) are rated for 200 volts, and you can easily drop that voltage in tube amps.

Yes bad use of wording by me, jacketed is more appropriate, as opposed to shielded, however, there are a ton of wires that would be suitable, meet UL (or other standards), and have a 600V rating. However, unless you passing near another wire and/or the case, you often don’t require jacketing at all, bare wire may be suitable (just like a PCB), as long as the wire is supported. The op is asking about internal wiring, which could be many spots. I normally recommend for those not great at soldering to invest in a stripper that is good with teflon wiring and then use teflon wiring as excessive heat not not significantly damage the jacket.

1015 is often used as it is very cheap and provides better protection and colder guaranteed temperature rating than 1569 for 277V circuits.