I don't think it would have been a toddler, Metro. They don't make puddles on the ground, they just go in their diapers. So potty training isn't relevant in this situation.
Wonnka - Do you have free will turned on? I can't imagine why the kid didn't go to the toilet. Also with electrocution, you normally get "singed" first with the chance to stay away from electrical objects for awhile. Then if you go right back to the repair, death can often result. Did your Sim get singed first?