Is there actually something in the electrical code that prohibits installing a 240 volt outlet wherever you want? I know people often install them outdoors for EV chargers.

(everything below assumes US and NEC / local electrical codes)

I don't think code prohibits it, but in my (not very educated) opinion, you might get into some gray territory if you try install them everywhere.

There are some safety related provisions which are mandatory for regular 120V (GFCI and/or AFCI), but I don't think they are required for 240V circuits. Building inspectors might have questions if you install these outlets everywhere. Although, again, I don't remember any limitation of where you can have them.

Another issue is the type of the receptacle. Apparently, Leviton makes receptacle that might be allowed in US and is combination of regular 120V plus European style 240V. However, it is only limited to 2.5A, which is very little (I think, this receptacle is primarily designed for hotels / shared spaces where you only want to charge your devices). Also, I don't think it has ground for 240V.

Probably, the best would be to use US 15A/20A receptacles (NEMA 6-15 / NEMA 6-20), which look very similar to the regular 120V ones (the difference is blades are horizontal).

However, I've never seen any actual plug using them (even though I did install these 240V in my garage, expecting some 240V equipment). But you can rewire plugs on your "imported" equipment / appliances.

There are also some interesting differences of the supply: in US it is typically split phase 120V+120V=240V, but sometimes (according to the internet) it could be 3 phase 120V with 208V between phases; in some parts of the world, it would be 3 phase 230V with 400V between the phases. This probably would cause some differences in how grounding works, might affect safety.

But yeah, generally, 240V should not be a problem. Power-hungry equipment (water heater, range, electrical dryer, EV chargers) -- they all typically use 240V already.

No, there is a proper us code-compliant solution for outdoor 240 receptacles - it’s that 4 prong 50amp one … you see them coming out of the ground at ski resorts, for instance, and they are also used on those outdoor PDUs you see at concerts and parades …

Edit: I think it’s a 14-50r.

Edit2: You almost certainly don't need these. A plain old 20amp 110 receptacle, on a dedicated circuit, GFCI, is a perfectly reasonable and code-compliant receptacle to put all over the outside of your house and will power anything you might need.

I can believe that a 15amp (pressure washer, weeder, etc.) might seem underpowered but I am skeptical that a 20amp one would be ...

Right, there are code compliant solutions. I was just musing over an idea of having 240V "everywhere" (including inside the house in every room, having 240V for special needs is, of course, a solved problem).

14-50R is not what I would use in that case, they are bulky, unsightly and don't offer tamper resistance.

6-20R / 6-15R have variants that are tamper resistant, and they look like regular outlets.

"20A should be enough for everything".

We used to have 2.5-3kW kettles before we moved to US, which would require 20-25A (although, I don't think the math is that simple -- circuit breakers don't trip on "exactly 20A").

Also, the issue with 20A receptacles is that, again, I have never seen 20A plugs (NEMA 5-20P) on appliances (it has neutral connector "flat" rather than vertical). Which is understandable, why make them if nobody has 20A receptacles anyway. There is a requirement to have two 20A branches in a kitchen, but commonly they are wired to 15A receptacles.

Your anecdote about coffee makers is a good one - it bears repeating that one of the most intensive household loads are old-school coffee percolators, etc., and many school and church kitchens have circuits just for them.

As for 20amp, it may interest you to learn that I have a commercial microwave with two magnetrons that is actually 20amp (and has the horizontal pin, etc.).

Yeah, it shows that I have zero knowledge about commercial appliances. I guess, I wouldn't be surprised if they routinely use 20A plugs / receptacles. Would make sense. Maybe, hospital equipment, too?

You would routinely see IEC sockets in use in Europe in commercial kitchens, factories, anything outdoors like a music festival etc. Partly it's for higher power appliances (including 3 phase power), but also the waterproofing.

They're also the socket found in datacentres (in Europe) to connect a UPS or PDU.

Home users see them at campsites, marinas, and for charging electric cars without a special car charger.

https://en.wikipedia.org/wiki/IEC_60309

I actually have a set of 4 20A receptacles within about 3' of me. I had to have an electrician wire a dedicated line, the main cost was the labor, might as well use 4-wire cable wired to 240V, I got 4 120V outlets out of it and he used the 20A type that takes either the usual household plug or the 20A version.

Wiring 240V is (typically) not an issue, as it is standard (in the US) to get 240V from the transformer to the house. The devil is in the details: what current would you wire it for, what receptacle are you going to use and what are you going to plug there.

ICE-powered pressure washers go up to 4,000 psi. I have never seen an electric pressure washer above about 3,000 psi and they're usually no more than the ballpark of 2,000 psi.

Your high power examples are all either dedicated wires (no outlet) or single-use outlets (like the dryer.) I'm saying there is no general use high power outlet permitted.

People install 240V outlets for EV chargers, RV's and hot tubs quite regularly. They usually don't break code to do so.

And those are usually 240V/50A outlets, a lot more powerful than the 240V/12A outlets of Europe.