User blog comment:Xilinoc/Ch. 580 - THE LIGHT/@comment-24913480-20140514092956/@comment-11051098-20140514160420

Regarding Kenpachi:

You have to remember that electricity is a dangerous thing. According to Wikipedia, only 50 volts against dry skin in the chest area is potentially lethal to the heart. Who knows how many volts Kubo put into Candice's thunderbolts. He could intend to make her thunderbolts as powerful as 1 million volts.

Besides, how many times have Kenpachi underestimated his opponent's power? Ichigo, Nnoitra, Royd/Yhwach, to some degree post-release Yammy. He probably thought he didn't need to remove his eyepatch to kill a girl.