Could be a small DC fridge but more likely it's an AC Lines voltage shock. Certainly if the equipment was faulty or the ground was bad, and the TS touched the fridge AND ground, i.e. water faucet or other pipe, the level of the shock can be anything from 60 volts up to lines voltage. If it was full lines voltage the TS would be scared as all get-go. Given the level of concern reported it would seem more like a low voltage shock. But most likely AC voltage.mini fridge freezer combo.
Same here. I‘m sure that our transformer supplier has an old bloke who goes round with file and sharpens up the frames before shipping them out.I've had more physical damage from an electrical shock by the sudden and rapid pulling my hand away from the source of the shock only to find some sharp object in the way of the travel of my flesh.