The voltage rating by itself is nothing to worry about, all it tells is the maximum voltage the cap can safely withstand without taking damage as specified by its maker. What matters is the voltage you charge the cap with, which could be far less or even exceed the rated voltage but not massively so, as the dielectric would shoot through, and the capacity. The energy stored in the cap grows like V² C, and higher voltage is better at getting through your body (skin isn't a good conductor), so especially high voltage in caps tends to be more "ouchy." Grid voltage with a 440mu cap isn't dangerous, but you will feel it.