Running the same wattage device at 240V instead of 120V would decrease the amperage, assuming the device was designed to handle either voltage.
My desktop PC uses about 600W running at full tilt. It can take 120V or 240V. At 120V, it will pull 5A to run its 600W load. At 240V, it'll only use 2.5A. This means for the same gauge of wire, it'll experience less resistive losses and thus be cooler and less prone to overheating.
You wouldn't change the outlet to a higher amperage outlet, you'd just change to the 240V equivalent of that same amperage rating. For the US, it looks pretty much the same as a regular wall outlet but has the blades horizontal instead of vertical. Something like this:
> Running the same wattage device at 240V instead of 120V would decrease the amperage, assuming the device was designed to handle either voltage.
Well yes, but usually the whole point of switching to 240V is to get more power than what 120V can supply. The people complaining about electric kettles being “slow” in the US compared to the EU would still be complaining if those kettles always pulled the same number of Watts on both 120V and 240V, because it's the Watts that determine how fast the water heats up. The amperage is therefore probably going to be at minimum approximately the same in that case — and probably higher if you're doing something more intensive (and therefore requiring more current) with that new 240V outlet than just running an electric kettle (like running a stove or a clothes dryer or an air conditioner or an electric car charger or a rack of 10+ of those 600W-PSU-laden computers — hence those usually getting beefier 20A+ circuits while everything else in a house might be 15A).
