Abstract: An electric submersible motor-driven pump includes a pump housing (2) in which is located a pump motor (3) and an associated impeller (4). A separate detachable float and switch housing (6) is detachably connected to the pump housing (2) and defines a substantially elongated upright chamber having a longitudinal axis in which an elongated float (8) moves for operating a switch arm of a switch whose electrical components are isolated from the fluid being pumped. A switchable adapter plug exteriorly of the housings is rendered operative by the electrical components upon movement of the float (8) to selectively energize or de-energize the pump motor (3).