Solar Pump Installations: How to Size Submersible Flat Cable for Maximum Efficiency
The world is growing exponentially and with it, its energy needs. The shift from traditional energy sources to renewable sources is very apparent and, moreover, more important than it was ever before. This has put solar energy in a new light, and it’s becoming one of the most go-to renewable sources.
If you are a renewable energy advocate and operate in the agricultural sector, you might have already witnessed solar pumping transforming the Indian agricultural landscape by enabling complete control over your energy needs while offering an unparalleled cost advantage.
The problem: With all benefits in consideration, the main hurdle stands to be efficiency. In a solar setup, every watt-hour counts. Many buy expensive pumps and high-grade solar panels, yet face considerable efficiency drops.
The reason: Because the submersible pump cable transporting the energy you tried so hard to generate is inferior!
Even small discrepancies in the size, material and conductivity of your cable will bleed your panels and motors dry, causing considerable setbacks and significantly increasing overhead costs.
In this guide, we will walk you through all technical and practical considerations so that you can choose the submersible flat cable that aligns exactly with your power requirements.
How a Solar Pump Works and Why the Cable Matters?
Before we address the problem and seek solutions, let’s dive into the basics. Solar pumps work on electricity generated by the solar panel which relies on a very specific output range of your panels. If the cable connecting your setup is not sized properly, it causes an electrical resistance. This resistance results in a voltage drop, forcing the motor to draw more power. This is not much of an issue for systems backed by a steady supply of power. But solar-powered systems operate on limited power. A voltage drop results in Overheating, Performance issues, and Equipment malfunctions. Hence, proper sizing of the submersible is critical as it ensures the power reaches the motor efficiently.
The Ultimate Sizing and Selection Guide for Flat Submersible cables
Flat submersible cable, especially the 3 core flat cable, operates on one objective: Reduce size and not the efficiency.
They are designed to operate even in harsh conditions such as submersion in water and other reactive chemicals and oils. Their flat profiles allow for easier handling and installation, making them ideal for applications ranging from water pumps to submersible lighting systems.
For pump installations, a submersible cable runs alongside the delivery pipe allowing access in narrow spaces, and moreover preventing twisting and overheating.. Let us narrow down on a few specifics to help you size your next submersible cable to suit your solar pump system.
The 4-Step Checklist for the right size
The 4-Step Checklist for the right size
1. Motor Maximum Current (Amps)
Horsepower (HP) and kilowatts (kW) are important considerations. But ensure you take all specifications into consideration, especially the Full Load Amperage (FLA) rating. The submersible cable must be able to handle this continuous current safely, plus a buffer of about 25% for safety and starting surges. This is crucial when selecting a 3 core submersible cable for your system.
2. Total Cable Run
Most people measure the borewell depth, order that exact length of cable, and expect it to work fine. It seems logical, but it is one of the most common and expensive mistakes we see in the field. Your total cable run is never just the depth of the borewell. Here is what actually goes into it:
Borewell depth: From the surface down to where the pump motor sits
Surface routing: From the borewell head all the way to your solar controller or inverter panel.
Slack allowance: A minimum of 2 to 3 meters extra, to ensure the cable is not under constant tension, and you can service the pump without a struggle.
A quick example: A 45-meter borewell with 8 meters of surface routing needs a minimum 56-meter (53+3) cable run. Ordering an exact 45-meter cable without accounting for surface routing and slack allowance proves costly in no time. It forces unnecessary joints, creating potential failure points underground.
3. Allowable Voltage Drop
For solar pumping applications, you generally want to keep your voltage drop under 3% to 5%.
Always consult a standard sq.mm cable sizing chart provided by manufacturers to cross-reference your current (Amps) and distance (Meters) to find the exact square millimeter (sq.mm) size that keeps your voltage drop in the safe zone.
4. Choose the Right Cable Profile
For borewell installations, Flat submersible cables have always been the go-to choice. The 3 core flat cable is the industry standard for three-phase AC solar pumps, providing a robust and uninterrupted connection
Other Key Factors to Consider
- Material – Choose the material that aligns with your needs. Cheaper alloys increase resistance by manyfold, making sizing a challenge. Aim for 99.9% pure copper for maximum conductivity and efficiency in all cable submersible pump applications.
- Insulation – The insulation must withstand high temperatures and prevent any contact with water.
Cables with thermoplastic elastomer (TPE) or polyvinyl chloride (PVC) insulation prove to be the most effective in volatile environments. - Gauge – Wire gauge is a measurement of wire diameter. This determines the amount of electric current the wire can safely carry, as well as its electrical resistance. A lower number indicates a thicker wire, which can handle more current and vice-versa.
For instance, applications requiring higher power levels, such as deep wells or high-output pumps, generally need a thicker gauge wire to prevent overheating and loss of power. - Environment – Temperature variation, moisture content, and exposure to chemicals, toxic or abrasive materials highly influence the type, thickness and length of the cable. For instance, Rajasthan’s dry, high-temperature climate is far more demanding on your cable insulation than most other regions. Heat and moisture will gradually degrade your insulation if you do not account for them. For deep borewell installations under such conditions, high-grade PVC or TPE insulation is the minimum standard you should be aiming for.
- Manufacturer – It is always recommended to compare manufacturers and partner with a submersible cable manufacturer that is reputable and best suits your needs. Certifications, data sheets, and user reviews/case studies further enhance credibility. Partnering with a reputable organization such as BMI Cables means you have chosen the best submersible cable manufacturer for your business goals.
The 4-Step Checklist for the right size
The Takeaway
The demand for renewable energy is now bigger than ever and solar energy stands out as the primary renewable energy source. For those operating in the agricultural sector, this proves to be a boon as solar pumps enable efficient and sustainable irrigation at significantly lower costs, provided they are installed and maintained properly. Submersible flat cables play a crucial role in the overall utility and efficiency of your solar pumps.
This is where BMI Cables stands out as one of the leading submersible cable suppliers, offering consistent material quality, Strong process control, and Access to engineering support. Our state-of-the-art infrastructure spans a corporate office in New Delhi and a state-of-the-art facility in Bhiwadi, Rajasthan. We operate as a trusted part of the ESS ELL Cable Group and follow ISO 9001:2015-certified processes.
As a leading industrial cable manufacturer in India, BMI aims to provide value, not just materials. Our partnership extends beyond mere transactions and we manufacture the best-in-class cables for all your needs.
Every inferior cable is working against your solar efficiency and output. Take control of it.
Reach out to our engineering team today, and get a specification built around your exact requirements.
Frequently
Asked Questions
For solar pumps, aim for 3% or less, as you are already working with limited power and any further drop will significantly affect the water delivery.
Not at all! A deeper borewell means a longer cable run, and therefore more resistance. The required cable thickness increases along with the depth.
Copper conductivity is far superior to that of aluminium. This makes copper the preferred option as less resistance means less voltage drops.
The resistance goes up, the cable runs hotter, and your motor wears out faster. In a solar setup, this means less water delivery.
Ask for valid proofs and certifications such as conductor purity, insulation material, certifications, and actual test data. A decent manufacturer will have this ready. Moreover, infrastructure, manufacturing processes, and standardization are other key factors worth considering.