When I visited south america in 2006, I immediately noticed the water heating systems directly built into the shower heads. They were basically omnipresent, in

When I visited south america in 2006, I immediately noticed the water heating systems directly built into the shower heads. They were basically omnipresent, in every hostel I stayed at. I am a software person, with only bare minimum EE understanding. But this setup spooked me a lot. But after a few rounds, you think to yourself: "They are using this stuff around here everywhere, it can't be as dangerous as you think." Let 5 weeks pass, and I enter the shower in a hotel in Cusco, Peru. Showering was fine, until I tried to turn off the water, which closed the loop. I have to say, I am pretty happy south america only has 110V. I had to wrap a towel around my hand to be able to close the valve. So, I was right in not trusting this stuff. Its weird and dangerous. But its apparently omnipresent in the countries down there...