> Here in the US I've heard families earning from $30k to $200k, working jobs from manual labor to white collar, call themselves "middle class."
$200K is definitely considered middle class in the US, especially by the left. For example, both Clinton and Sanders use $250K as their upper limit[0].
As for manual labor vs. white collar - it depends on what context you're talking about, but in terms of sheer economic purchasing power, that doesn't really matter that much. (Incidentally, a lot of white-collar office jobs pay a lot less than many blue-collar positions). There's definitely a class and status aspect to the term 'middle class', but that's much harder to quantify (and is also only loosely correlated with income - hence the existence of the term nouveau riche.
As an aside, $200K isn't necessarily as much as people think it is, which is (one of the reasons) why people like Clinton and Sanders consider $250K to be middle class[1]. A lot of people who "make" $200K in gross income are often working jobs which require them to cover a lot of large expenses (such as vehicles/equipment) out-of-pocket, or are running their own businesses[2]. While they might seem rich if you just look at the $200K figure, that doesn't mean they're really rich in any meaningful sense of the word - even if they're frugal, they could still be living quite hand-to-mouth on that amount.
[0] http://money.cnn.com/2016/02/18/news/economy/clinton-sanders...
[1] There are more cynical, political reasons for doing it as well, but there is a factual justification for it as well.
[2] I'm not talking about startups, but genuine 'small businesses', for which they're often the sole proprietor or one of very few partners.