30V... 50V... 75V... it doesn't really matter. None of these voltages will develop enough current to kill someone. The capacitor, maybe, because it will instantly discharge everything it's got in a rather short amount of time.
The training I recieved from the military stated that a person's natural resistance is somewhere around 1M ohms. The lethal limit is typically 1A in 1 second, according to what I absorbed. Now, a person's resistance to electric current varies, according to body composition, how tired you are, sweaty, soaking wet, emotionally unstable, etc., so calculating for 1A is different for different people. Right now I'm 1.6M ohms, according to Mr Fluke.
Anyways, @ 75V, with ohms law:
75V / 1M = 0.075 A, or 75mA, which is hardly lethal.
750V / 1M = 0.750 A, or 750mA, which under adverse circumstances could be.
There's the time aspect, in which if 750mA was not lethal to you initially, it could be over several seconds or longer. There's also intrance/exit wounds from arcing, etc, but I don't think any of this would be a concern at the voltages we're talking about here.
The main concern here would be stored potential in a coil or capacitor. Now that stuff hurts! (personal experience)