Does 220 REQUIRE 12/3?

Recently replaced an old Cutler-Hammer circuit panel with a new square D box. The only thing plugged into this panel is a well pump (for right now). As I was unhooking the old box, I noticed that the well is running 220v through 12/2 wire, with both the black and white being hot. It's been working like this for years, so I'm wondering if it would be absolutely imperative to rewire it....

Thanks,

ranger_dood

Some pics! Because we all love pics....

Old box, as it sits now (after being disconnected, but I can't get that one unused line unhooked... gonna have to cut it).



New, 6 circuit SquareD box.



BTW- the old C-H box was working fine, but it used some goofy-*** breakers and the other two panels in the garage/barn are new SquareD panels, so I wanted to have all QO breakers. Plus the new panel just looks so nice, and is probably a bit safer.

No, 220V devices like this only require 2 hots and a ground.

Where's the romex go? Under the ground?

No, it goes down to a service disconnect, identical to this one:



From there, it goes to the pressure regulator for the tank, and then out to the well in proper conduit