I'm not sure if this is a case of selective memory, or if it's real.
It seems that Americans do not use the term "mains power," which is common in British English. The closest synonym I know is "wall power," which is imprecise.
As an American electrical engineer, I don't want to flip-flop dialects, and "wall power" is both naive-sounding and awkward when referring to 120 V inside a device or otherwise far from a wall.
Is there a better term I should know, or should I assume that "mains" is mainstream to my fellow Americans?
Edit: According to Wikipedia:
In the US, electric power is referred to by several names including household power, household electricity, powerline, domestic power, wall power, line power, AC power, city power, street power, and grid power.
This insinuates that "mains" is not an American term, and that the alternatives are all equally imprecise.
Conclusion: Americans are likely to use mains as a synonym for grid, which isn't baseless. So really the British style only seemed better because I hadn't yet considered whether the word already has another meaning.