Pump Cable Wire Differences

When working with Pump Cable, there can be some confusion surrounding the difference between 2 wire, 3 wire and 4 wire cables since the terminology around it has evolved over the years.

Pump Cable typically has a red wire, black wire and green wire but can also include a yellow wire. The green wire is the "ground" wire, so most of the confusion actually comes from some people not counting it as a wire as it is not considered a "power conductor".

In this blog, we will explain the different methods of referring to pump cable that you will run into in the Industry. Let's get into it.

Typical Pump Cable Description

To start, it's important to know that neither method is wrong. Some people describe the TWU14-4-2 pump cable by the type of motor installed onto the submersible pump. Others refer to the actual number of wires the pump cable has. Like mentioned before, the green pump cable is often not counted in the number since some people don't consider is a "power conductor."

Years ago, you used to be able to purchase pump cable that did not include a "ground" wire. This meant that the installer had to run an additional separate ground wire along the side of the pump cable to ground the pump. Sometimes this could result in installers failing to install ground wires, leaving a serious shock hazard.

During that time there were actually two wires (black & red, no ground) for two wire pumps and Black, Red & Yellow for three wire pumps (no ground, while Black, Red, Yellow and Green were also sold for three wire pumps, which is still the normal for three wire pumps today).

Quick Breakdown

Two Wire Pumps = Three wires - Two Conductors (Black & Red) & Third Green Ground wire

Three Wire Pumps = Four wires - Three Conductors (Black, Red & Yellow) & Fourth Green Ground wire

Which type of Submersible Pump is the best, Two wire or Three wire?

Ultimately, a Professional Pump Installer should discuss the options with you, but we can provide you with three things to consider.

1. Something that plays a major role in the decision is the horsepower. If you are needing to supply a sufficient water volume and pressure for your water system and is sizes to require a motor larger than 1 1/2" horsepower, then the best option is to go with a three wire well pump, ensuring it starts and ends properly. If your application does not require a pump with higher horsepower than 1 1/2", then it could come down to a few other decisions.

2. If you are wanting to maintain or replace the starting components of your pump without needing to pull the pump out of the well, your best option is a three wire well pump. Three wire pumps might have a higher upfront cost, but the ability to replace individual components inside the control box is worth it and they also typically have a longer life expectancy.

3. If you want to keep the initial cost low with an easier installation, a two wire well pump might work best for you. A downside is that you will have to replace the entire submersible pump if something major were to take place. In lower horsepower pumps, the choice often comes down to your personal preference. The major difference between a two wire and three wire pump is where the motor starting components are located.

In three wire pumps, the motor's starting components are in a "control box" that is located above ground in the well house or in your basement.

In Conclusion:

Completely understanding which number of wire pump cable you need for your application will ensure you select the correct one. Keep in mind, different people use different terminology so be sure to confirm before purchasing.