I have a switch for a water heater. The electric kind that heats instantly overhead as you take a shower. I am an electric engineering student and I am very curious. This switch has six terminals yet it controls one heater. Anyone who has an idea how this is so and how the wiring diagram would look. The switch has a red light that is on when it is heating. But two of the terminals are separate from the rest and on both sides they end up where the screws to the patrice box are. Hence I they must be for earthing. Can anyone help please?
Photo of the item in question: