FAQ - Pump Irrigation
When are submersible pump cables used?
Submersible pump cables are specially designed to supply power to underwater pumps and irrigation motors, although they can be used for other applications as well. They are generally resistant to water, oil, sunlight and weather of all kinds and so are preferred for use in hostile terrain and environment. You will find 3-4 color coded conductors with specially developed insulation. They come with a good level of flexibility, abrasion resistance and mechanical protection. The cables come tested for durability, strength and performance.
What are the distinct qualities of the conductors used in submersible cables?
The conductors come in flat or round as seen in the cross section and they are rated primarily rated for 600 V. They are made of soft and uncoated Copper with low conductor resistance and good flux capacity as per industry standards (ASTM B3 and B8). Depending upon the usage, you can get the cables with control wires and power conductors. The conductors come color coded with the following specifications:
- Red – positive (start winding)
- Black – negative (run winding)
- Yellow – main hot
- Green – ground
What type of submersible pump cable is most suitable for wells?
Most cables will come with a code or a stamp which will show the user whether the cable can be used for well water. UL listed Type THW submersible cable can be used for most purposes, including wells where flexibility of cables is required. These cables are resistant to friction, oil and grease. The cables come with specially designed insulation and jackets which makes it ideal for industrial use. Look out for PVC insulation or EPR insulation, which has high resistance to oil, grease and water, low swell quality, mechanically stable and chemically inert. The cables come with an overall jacket and some also come with a double jacket. The jacket will also be resistant to oil, grease and water with low swell quality and will be mechanically stable and chemically inert. The cables can be installed easily as the conductors are bonded together for easy separation, while providing flexibility and mechanical protection at the same time.
What type of submersible pump cable is recommended for heavy duty purposes?
The “UL listed Type THW heavy duty flat submersible pump cable” can be used for a variety of purposes where extra mechanical protection is required. The Type THW is a PVC compound which provides better insulation. Places where there is a call for extra strength and durability, cables with double jacket and EPR insulation are recommended. The jacket comes with an impenetrable web, which can be stripped off easily during installation. The design of the jacket provides flexibility and mechanical protection at the same time.
What type of cable is suitable for irrigation systems?
UF/Type TWU among other types can be used for irrigation systems for general purposes, such as power and lighting. You can select cables that have solid or stranded copper conductors that come with individual PVC or EPR insulation. They are designed to withstand the extreme conditions to which they may be exposed to, and are resistant to water and moisture.
The UF-B Underground Feeder Cable comes with a flat parallel design and a non-insulated grounding conductor. The outer jacket provides the much needed protection and so is made of strong PVC.
Do I buy a 2 wire system or a 3 wire system for my well?
Actually, it is a 2 plus 1 green ground wire and a 3 plus 1 green ground wire that we are talking about. Generally a 2 wire pump might be a little bit cheaper and is definitely easier to install. However, you will appreciate the 3 wire system when you have to do repairs as it will have a control box above the ground. The 2 wire system, on the other hand, will have the “controls” inside the underwater motor and so you will have to think of pulling the motor up to check what’s wrong.
Do I need to replace the cables when I put in a new pump?
If there is no wear and tear to the jacket and insulation, you can re-use the old cables as they are made to last a long time and are really durable. However, if you are replacing your old 2 wire system with a 3 wire system or vice versa, it is best to buy new ones that will suit the system.
How do I measure the correct gauge wire for the submersible cable that I need?
To determine the correct gauge wire needed, choose the correct voltage, phase, and horsepower required. You must also take into consideration the length required for the cable, as the pump might be a few hundred feet under water. For example, a 14 AWG will be required for a distance of 270 feet, for 1 horsepower and a 2 wire cable. You will also have to determine the life span needed for the cable, as the pumps will be untouched and underwater for a really long time.
Can the submersible cables be used in extreme temperatures?
Generally the cables, be it flat or round, can be used for conditions up to 75OC, when the voltage is around 600 V. It can work even when the temperature drops as low as -25OC. The cable can work in such temperatures, even at a depth of 900 feet. However, the cable has to be designed keeping the industry standards in mind.
In case of a fault, do I cut the wire to take readings?
This is not necessary as you can take ohm readings instead. You can take the readings from both ends to determine where the fault could lie. Alternately, you can also use a clamp-on ammeter to check whether there is a fault. In case, you have to dig, then you can start mid way to determine which half is at fault. This will reduce the amount of cutting that you have to do.