Selecting and Sizing Submersible Pump Cable

Selecting and Sizing Submersible Pump Cable

For nearly a century, submersible pumps have been an effective solution for transferring water from well systems to its final destination inside a structure or house. This well water pump stands out in the fact that it can be installed without the worry of freezing as it’s totally submersed in the fluid which is being pumped. One of the components that aids in the pump’s performance is the submersible pump cable.

The submersible pump cable is used from the service box to the wellhead and from the wellhead to the pump in submersible applications (see diagram on next page). The cable is approved by Underwriters Laboratories (UL) for underwater duty and is designed to safely carry electrical loads inside water wells so long as it is sized properly.

There are two main components to a submersible pump cable, which first includes the conductors. These copper wires conduct electricity and come in many sizes. The smaller cable is identified in American Wire Gauge (AEG) sizes from #14 on the smallest end to #4/0 (pronounced four OTT) on the largest end of the scale. Beyond the AWG sizes are the MCM sizes, which start at 250 and go up to 2,000. The other component of a submersible pump cable is the insulation, which is defined as plastic or rubber material covering the copper conductors to keep the conductors from shorting between themselves or to ground.

Properly sizing the submersible pump cable for an application is crucial to the operation of the pump itself. Doing so involves a calculation based on a number of factors, such as the following:

• Horsepower (HP) of the motor
• Voltage and phase of the motor
• Distance from the breaker panel to the motor
  • Sum total of the drop + offset (also known as wire in the ditch or lateral run) + distance through the house to the service entrance
• Code requirements

Most of the factors taken into consideration for submersible pump cable sizing are commonly utilized together in a sizing table that is available from your submersible motor manufacturer. Submersible pump cable sizing tables list the maximum number of feet of each sizing cable you can run from the service entrance to the motor for each horsepower motor. 

When it comes to installing a well water pump and all the parts it’s composed of, there’s little room for mistakes. Thanks to the cable sizing information provided by submersible motor manufacturers such as A.Y. McDonald, you can rest assured in the fact that you’ve selected the right size for the application at hand. For more information on the topic, take the ‘Selecting and Sizing Submersible Pump Cable’ AYU course, call us at 1-800-292-2737, or visit aymcdonald.com.