I think the plot was something like a serial murderer got the electric chair and when he died his spirit went into the electrics. He then moved about and killed people that had got away or were on the jury? Anyway, using his new supernatural powers he makes a guys kitchen into a giant microwave and all the popcorn in the cupboard popped. The kitchen got so hot the guy melted/exploded. Gave me nightmares when I was little.