MV Reeling Cable vs Low Voltage Reeling Cable: Key Differences and Applications

In the modern world with terminal ports, extensive mines, and industries, mobility is of utmost importance. Machinery such as shore-to-ship cranes, stacker reclaimers, and electric excavators must operate throughout the day and night without any power interruption. And that is where the reeling cable becomes a crucial component.

There are generally two kinds of reeling cables used in power systems of mobile machinery: MV reeling cables, which stand for medium voltage reeling cables, and LV reeling cables, which indicate low voltage reeling cables. The following guide covers core technical differences, application scenarios, and maintenance strategies to help you make an informed decision.

A massive red gantry crane towers over the dock, featuring a large circular cable reel with thick black cabling wound around it to power the machinery.

What Makes MV Reeling Cable and Low-Voltage Reeling Cable Different?

This difference not only involves safety ratings but will determine the overall design and power rating of the cable itself.

1. Voltage Range and Electrical Capacity

Low-voltage reeling cables normally have voltages less than 1,000 volts (either 600 volts or 1,000 volts). These are the workhorses for smaller-scale mobile equipment. In contrast, MV reeling cable is designed to handle much higher electrical stress, with standard ratings ranging from 3.6/6 kV up to 18/30 kV. This higher-voltage capacity enables the transmission of the massive amounts of power required by heavy-duty industrial motors.

2. Construction and Insulation Thickness

Since high voltage produces a higher electromagnetic field intensity, the inner construction of medium voltage (MV) cables is highly complicated.

Insulation: MV cables have much thicker insulation materials (usually, ethylene propylene rubber, or EPR) to be able to hold the high voltage and avoid such problems as "arcing."
Shielding/Screening: In contrast to low voltage (LV) cables, MV cables have semiconductive layers and metallic shielding screens (copper wires).
Size of Conductor: It seems paradoxical that, in comparison to LV cables, an MV cable has a smaller cross-section of conductors when both are needed to transmit the same power. This happens due to the increase in voltage, making it possible to reduce the value of current (I) while keeping power constant (P = V ✖ I).

3. Weight and Voltage Drop

Voltage drop is the loss of electrical pressure that occurs as electricity travels through a conductor. It is a major concern for mobile equipment that moves over long distances.

LV Performance: At low voltages, current must be very high to deliver high power. High current generates heat and a significant voltage drop over long cable runs. To combat this, LV cables must have very large (and heavy) conductors.
MV Performance: Through the application of the MV system, there will be an ability to transfer energy over large distances without any significant loss in efficiency. This low amount of current results in cables that are not heavy on the reels.

Comparison Table: MV vs. LV Reeling Cables

Feature	Low Voltage (LV) Reeling Cable	Medium Voltage (MV) Reeling Cable
Voltage Rating	Up to 1kV (600/1000V)	3.6/6kV to 18/30kV
Typical Insulation	EPR or PUR (thinner)	Thick EPR with semi-conductive screens
Weight for High Power	Very heavy due to large conductors	Lighter due to high-voltage efficiency
Voltage Drop	High over long distances	Low/Minimal
Shielding	Optional (usually for data/control)	Mandatory for electrical stress control
Installation Cost	Lower initial cost	Higher initial cost (materials/termination)

Common Applications for Each Type

The next stage in choosing the right cable lies in understanding the kind of environment and power requirements that your machines require.

Low-Voltage Reeling Cable Applications

Low-voltage cables are best suited when dealing with a “distributed” power scenario wherein the machines are small in size, or the range of movement is short.

RTG Cranes: Rubber Tire Gantry cranes found in container yards utilize LV reeling cables due to their mobile nature.
Handling Machines: Small conveyors, lumber handling machinery, and palletizing robots use LV cables since the required power input does not warrant an MV system.
Harsh Environments with PUR Jackets: In many automated warehouses, LV cables with polyurethane (PUR) jackets are used. PUR is exceptionally resistant to abrasion and chemicals, making it perfect for smaller reels that cycle thousands of times a day.

MV Reeling Cable Applications

When the scale of the operation increases, the MV reeling cable becomes the only viable technical solution.

Ship to Shore STS Crane: These giant cranes consume a huge amount of energy for the lifting of huge containers at a fast pace. In order to avoid losing too much energy and dealing with the weight of the wire rope on the drum, MV is commonly used.
Mining Excavators: In surface mining, electric excavators operate in large open areas. MV enables these devices to get electricity from a substation, that is at some distance, without experiencing voltage fluctuation.
Stacker Reclaimer: These devices are used in bulk materials handling, like in a coal or ore yard, and move over a long rail track. Therefore, MV is usually preferred for a better voltage supply at the motor ends.

How to Choose and Maintain Reeling Cables for Your Project

The cheapest cable is not always the best since selecting a cable based on cost can lead to "false economy," where the initial savings from purchasing the product end up costing you ten times more.

Selection Criteria

Determine Total Power Load: Find out the maximum current load. If you have situations involving heavy loads and lengths of over 100 meters, calculate voltage drops. If the voltage drop exceeds 5%, then MV may be necessary.
Reeling Method: Mono-spiral (winding of cables around themselves) or random winding? The monospiral requires cables that are resistant to tensile forces, whereas random winding demands cables that have high abrasion resistance.
Environmental Issues: Sunlight, temperature, and contact with chemicals like hydraulic fluids and salt spray. For example, a cable used in a Siberian mine requires a specialized "cold-flexible" jacket that won't crack at -40 degrees.

Maintenance and Longevity

Even the best-reeling cable will fail if poorly maintained. Follow these professional guidelines:

Regular Visual Inspection: Check for "necking" (where the cable diameter thins due to over-tension) and jacket cuts. For MV cables, pay close attention to the termination points; any signs of carbon tracking or discoloration indicate an impending electrical failure.
Clean Reeling System: Dust, dirt, and ice may accumulate on the drum or within the guide pulleys. These particles work like sandpaper, scraping the outer insulation layer of the cable.
Alignment Check: Make sure that the cable is aligned properly on the drum. Otherwise, the cable will be rubbed against the flanges of the drum, resulting in premature wear.

Conclusion

MV reeling cables are better than low-voltage reeling cables due to their higher power capacity and lighter weight. Low-voltage cables have a shorter lifespan due to poor heat dissipation. On the other hand, MV cables dissipate heat better and are suitable for longer and heavier applications.

Do you need to install a power cable for port cranes, mining machines, and conveyors?Contact us now! We are happy to help you by supplying excellent reeling cables depending on your specifications.

FAQs

1. What is the primary function of a reeling cable?

The reeling cable is used to deliver energy or control signals to equipment that moves around. The structure of this cable enables it to wind and unwind on a drum without being affected by the forces of stretching, bending, and twisting.

2. At what voltage does a cable become "Medium Voltage"?

Depending on various standards, the range between 3.6kV and 30kV is usually referred to as "medium voltage." Voltages lower than 1kV fall under the category of "low voltage."

3. Why is an MV reeling cable often lighter than an LV cable for the same power?

Higher voltage enables lower current flow while transmitting the same amount of power. As conductor size depends on current flow capacity, an MV cable can operate with smaller conductors, which makes it lighter than an LV cable with extremely large conductors that are needed to avoid voltage drop.

4. Can I use a standard flexible cable on a reel?

No, it is not. A regular flexible cable is simply not designed to withstand the tensile forces required for winding and unwinding. Winding a non-reeling cable will damage it by breaking the internal conductor or making it twist like a corkscrew in no time.

5. How do I prevent my reeling cable from twisting?

Install a cable without any pre-twist and ensure perfect alignment of the drum and guiding pulleys. It is best to use a cable that has anti-torsion braiding incorporated into the design.

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about HEBEI- HUATONG

Founded in 1993, Hebei-Huatong is a global cable manufacturing enterprise with production facilities located in Tangshan (Hebei Province, China), Busan (South Korea), Panama, Kazakhstan, Tanzania, Cameroon, and Angola. Its core product portfolio includes submersible pump cables for oil extraction, flexible moving cables for harbor cranes, cUL/CSA listed cables for AI PDU and marine shipboard cables. The company provides robust support for the continuous, safe, and efficient operation of industrial sectors worldwide, including offshore and onshore oil & gas exploration, and material handling via port cranes.