Saw this story from New Zealand linked to from the Of Arms and the Law blog:
Policeman stuns himself
Nov 18, 2006
A clumsy constable attending a domestic dispute in Central Auckland accidentally shocked himself and a teenager with a taser gun before pepper-spraying an innocent woman, reports said on Saturday.
The constable was loading his weapon when he accidentally blasted himself with the stun gun's 50,000 volts while trying to stun a man at the centre of the incident last month, the New Zealand Herald reports.
Another shot hit the man's 16-year-old son.
After five attempts to hit the man, the officer eventually used pepper spray, but succeeded only in hitting the man's 21-year-old daughter, an unintended target.The wanted man eventually gave himself up.