[rsync]

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.).

[idubrov]

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?

[Symbiote]

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