Insufficient cross-section of the cable conductors, taking into account the length, leads to a voltage drop at the motor terminals, reducing the torque and increasing the current consumption. Increasing current consumption can cause the motor to overheat and shorten its life. Therefore, the cross-section of the connecting cable for the pump is selected taking into account the load in continuous mode, the length, the permissible voltage drop in the line no more than 3% and taking into account the economic justification.

Typically, cable failures between the submersible pump and the voltage source are caused by mechanical abrasion, thermal or electrical breakdown of the insulation due to aging, overloading, temperature cycling, or critical adsorption of water.

Dependence of the cross-section of the connecting cable on the length and mechanical power of the motor of a three-phase submersible pump - direct start, 3 x 400V.

Considering that the operation of the submersible pump is carried out in a flooded state, the operability and service life of the connecting cable is influenced not only by the parameters of the electrical, thermal and mechanical load, but also by the critical impact of the environment.

As a result, the choice of a power cable for connecting a submersible pump with a voltage source necessarily takes into account the parameters of the aggressive influence of the surrounding water: temperature, pressure, the presence of additional heat sources in the liquid, impurities and substances that cause aging, corrosion, surface pollution, algae growth and mold formation. A special waterproof cable is used for connection with a submersible pump.

Structurally, there are several types of submersible cables used to connect pumps in a well with a voltage source: round, flat and shielded cables. The most common and standard submersible cable design is considered to be round. The round cable of the H07RN-F brand with a rubber sheath and conductor insulation is widely used.

Flat cable is used, as a rule, where there are spatial restrictions inside the well or there is a need to minimize the overall diameter of the pump. As a rule, motors of multistage submersible pumps are traditionally equipped with flat cables to minimize the overall diameter of the pump when laying the cable laterally.

The shielded cable can be used wherever it is necessary to reduce the induction effect of high-frequency electromagnetic radiation when implementing the frequency control of the pump. Despite the tangible benefits of energy savings, accurate and constant process control, frequency control of a submersible pump also has negative components - electromagnetic emission, overvoltage and leakage points. These factors determine the use of submersible flat cables, including shielded ones, with improved insulating characteristics.