Wait, in the US you use 15A at 120v? Here in Europe (Spain at least) the typical is 16A at 240v. 1500W isn't that much of a problem. Oven breakers are even 20 or 32A.
Yep! The typical US residential circuit is only 120v, 15A breaker (so 12A at 80% load). (And that may be only 110-120v.) 20A circuits are also fairly common, but it's not the most common; the majority of wall outlets in a US house will be 15A.
In this chart, https://en.wikipedia.org/wiki/NEMA_connector#/media/File:NEM... , the commonly used US residential sockets are NEMA 5-15 (labelled "Typical Outlet," for 15A breaker circuits), NEMA 5-20 (for, duh, 20A breaker circuits), and NEMA 1-15 ("Old Outlet," in older buildings).
> 1500W isn't that much of a problem. Oven breakers are even 20 or 32A.
We do have higher amperage circuits for appliances like ovens and clothes driers, but they're usually dedicated circuits and have different socket shapes. You can see the labels "Clothes Dryer" and "Electric Oven" in the chart linked above :-).
And of course some datacenters just wire DC to the whole schebang instead of having an individual, well two redundant, PSUs per server.