I, too, have had a shock from the PRUSA i3 from the power source apparatus for the extruder. The mild shock came when I touched the left side of this area and was just a buzzing feeling in my hand. It is also where a 'caution' sign points to it. I am concerned as I am learning about these printers in order to introduce one to a high school in Honduras and it needs to be safe! Can anyone advise? I live in the UK and there is lots of humidity and damp this August and also no carpets are anywhere from the outdoors to the printers so that can't be the answer. Thanks, Em B.