Pleuger cavern pump units are single-stage or multi-stage centrifugal pumps which are typically coupled with water-filled motors as standard, or oil-filled motors for special applications. For this application the motor is assembled below the pump and the suction area is located above the motor. For cavern pumps, the power supply cable is contained in a water-filled protection pipe (water-filled motors with ATEX-certificate) or a special armored cable is connected with a plug to the motor (oil-filled motors). The special design ensures a safe operation in explosive atmospheres. Cavern pump units are manufactured according to customer specification only.