The pool guy doesn't leave me with a warm fuzzy. Wires crossed causing it to run hot? Doubt it. You can cross wires and get it to run backwards, or if he had it wired for 120 and it was connected to 240 that would be pretty obvious. Arcing? Could be a bad connection but that would be obvious as it wouldn't run well if at all. The motor is coming up to speed, isn't it? Not sure what to suggest next.
Al