[Kirby64]

240V-20A circuits will handle 3.8kW continuous. It’s probably a 240V-20A circuit, as that is what the power supplies typically want. Also, easy to convert an outlet to 240V, if the breaker is dedicated to that outlet. Just requires swapping the breaker and the outlet, not the wires.

[FireBeyond]

I don't think that's exactly common other than for outlets that are already wired for those specialized purposes, no?

Certainly on my panel the only "single outlet" breakers are hot water, AC, oven/stove, dryer.

[Kirby64]

I agree it’s not common. Doesn’t mean you couldn’t do that. If every room has its own breaker for the outlets in that room, you could convert that room to 240V, as an example, though.

Also, another place where you might already have this outlet: some older houses that use window AC units that were larger had 240V 20A outlets. Not common these days, but you can still buy these types of window AC units.