I often come across electric kitchen stoves plugged into a 240V receptacle that rather than being recessed into the wall like a normal outlet, is mounted in a electric box sitting on the floor, which is supplied by a two-foot-or-so run of BX cable that then disappears into the wall. The box and outlet can be moved freely around a few inches, although the cabinets to either side assure it sits on the floor behind the range. Is this safe, and is it up to (U.S.) code? I occasionally see same thing for clothes dryers too.

Thx.