Presumably, you would chop off the plug on the UK/EU kettle, and replace it with your own NEMA 6-20 plug. No need to install a UK/EU plug in your house. Also works good in case you need to use some sort of weird industrial equipment that needs 240V.
Does anyone make a.travel adapter that plugs into a us 240volt socket? Such a thing is easy to imagine, but most houses don't even have an outlet you could plug it into, so the demand would be small.
I would not use a travel adapter for a kettle. They pull major current, and the quality of the travel adapters is generally not intended for that much current draw...
