380V

The old French electrical system known as "triphasé", with three live wires and no neutral. Plug it in the right way and you get 240V, do it the wrong way and you blow your electrical devices.

My uncle told me the story of some English neighbours of his in the south of France, who didn't trust the local workers, so that came over with their own English workforce. The electrician had no idea that he was working with 380V and their fridge blew when the power came back on.

Not that I'm going to try plugging this one on myself, the photo was taken for posterity before I chuck it all away...