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 120V AC inside a device (but still coming from mains) 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, mains electric power (as opposed to battery electricity, etc.) 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 a U.S. term, and that the alternatives are all equally imprecise.
Conclusion: Americans are likely to use "grid" as a synonym for "mains", 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.
Best Answer
As another American EE, I would use "mains" only in certain contexts...
After the hurricane, the hospital powered life support equipment from diesel generators for 36 hours, then switched back to the mains.
"Grid" would also be acceptable.
If you're referring to 120VAC (RMS) without caring about source, the accepted U.S. industry-wide term is 'line voltage'.