Submersible pumps are devices whose entire assembly is submerged in the fluid to be pumped. They are usually referred to as Electrical Submersible Pumps (ESPs). They operate by pushing, rather than pulling, water during its pumping process and are featured as single stage or multiple stages. Each stage of a submersible pump consists of a motor in a casing, closed with mechanical seals to prevent leakage. The motor is connected to a cable that generates power to run the motor, and the casing extends to some sort of pipe or hose leading to the surface. Submersible pumps can be connected to different types of pipes, flexible hoses or wires, depending on the job and the liquid being pumped.