I know an assistant had a Norman pack that discharged on him. It's like getting tasered. He should have dumped the pack after turning it off. I think they're illegal to use in the European Union.
I worked with this guy back in the 90s, a big fashion shooter. He had all these Norman and Calumet packs that would just randomly go off like a gunshot KABLAM!! It was very disturbing. None of the assistants wanted to touch the packs and risk electrocution.