Well, a few days, and a couple of deaths actually, see here (tasered while in handcuffs), and here.

Let’s be clear on this: as long as Tasers are not designated lethal weapons, they will continue to kill, and as long as the police know that they can use them, and that they do not get automatic review that a peace officer does every time he discharges a weapon, police will continue to abuse this lethal weapon.