How NSSHOEU / NTSWOEU Submersible Cables up to 6 kV Keep South Africa’s Pumps Running Where It Matters Most

Why Submersible Cables Matter in High-Demand Environments

Delivering electrical power underwater is one of the most demanding tasks in cable engineering. Unlike surface installations, submersible power cables must operate continuously under hydrostatic pressure, moisture ingress, chemical contamination, and mechanical stress, often for years without interruption.

In South Africa, these challenges are magnified. From deep-level gold and platinum mines to municipal water infrastructure and wastewater treatment plants, submerged electrical equipment plays a critical role in keeping operations safe, compliant, and productive.

At the heart of these systems are submersible cables, purpose-designed to power pumps and motors that cannot afford failure. Among the most trusted solutions globally are NSSHOEU and NTSWOEU submersible cable families, engineered for voltages up to 6 kV and designed specifically for long-term underwater operation.

This article takes a deep, practical look at NSSHOEU / NTSWOEU submersible cables, explaining:

• Where and why they are used

• How they are constructed

• Which standards they comply with

• How to select the correct voltage and configuration

• Why they outperform conventional power cables in submerged conditions
  —all with real South African context and experience.

Typical Applications of NSSHOEU / NTSWOEU Submersible Cables

Industrial and Municipal Water Applications

South Africa’s water sector relies heavily on submersible pumping systems, particularly in regions where groundwater abstraction and long-distance pumping are essential.

Typical applications include:

• Municipal water treatment plants

• Borehole and deep-well pumping systems

• Raw water transfer stations

• Wastewater and sewage pumping installations

In these environments, cables must withstand:

• Permanent immersion

• Variable water chemistry

• Continuous electrical loading

• Limited maintenance access

NSSHOEU (0.6/1 kV) cables are commonly used for low-voltage industrial pumping, while NTSWOEU (up to 6 kV) cables are selected for deep wells and high-power motors, where voltage drop and current limitations make medium voltage essential.

Mining and Resource Industries in South Africa

Mining is where submersible cables are truly tested.

South Africa’s gold, platinum, and coal mines generate vast quantities of underground water that must be removed continuously to maintain safe working conditions. This process, known as mine dewatering, depends on large submersible pumps operating at significant depths.

Key mining applications include:

• Shaft sump pumping

• Underground dewatering stations

• Open-pit mine water management

• Process water circulation systems

These environments expose cables to:

• Oil and hydrocarbon contamination

• Abrasive slurries

• Mechanical handling damage

• Elevated ambient temperatures

• Continuous duty cycles

NTSWOEU 3.6/6 kV submersible cables are widely used in South African mines because they combine medium-voltage performance with robust rubber construction, offering reliability where failure is not an option.

Special Installation Scenarios

A unique feature of NSSHOEU / NTSWOEU systems is their suitability for vertical pump installations, particularly in boreholes and shafts.

In many installations:

• The ascending (rising) pipe acts as the earth conductor

• 3-core cables without a dedicated earth core are used

• Space constraints demand compact yet mechanically strong designs

These cables are specifically engineered for:

• Long vertical suspension

• Constant tensile loading

• Safe electrical earthing through metallic pipework

Applicable Standards and Compliance

International Standards

NSSHOEU and NTSWOEU cables are manufactured in accordance with established German and European standards:

• VDE 0250 Part 812 – Submersible motor cables

• VDE 0250 Part 813 – Medium voltage rubber-insulated cables

These standards define:

• Electrical performance requirements

• Insulation systems

• Mechanical robustness

• Test voltages and quality criteria

Relevance to the South African Market

While South Africa uses its own national standards (such as SANS), VDE compliance is widely accepted across:

• Mining engineering specifications

• Municipal water authority tenders

• EPC project documentation

For South African operators, compliance with recognised international standards:

• Simplifies safety audits

• Reduces project approval risks

• Enhances long-term reliability and insurability

Cable Construction Overview

The performance of NSSHOEU / NTSWOEU cables is rooted in purpose-driven construction, optimised for underwater operation.

Conductor Design

• Flexible stranded tinned copper conductors

• Class 5 flexibility according to DIN VDE 0295

Why this matters:

• Tinning improves corrosion resistance in moist environments

• Fine stranding enhances flexibility during installation

• Stable current-carrying capacity over long service life

Insulation System

• Heat-resistant EPR (Ethylene Propylene Rubber)

EPR insulation is preferred because it offers:

• Excellent dielectric stability under water

• Resistance to thermal ageing

• Superior performance under medium-voltage stress

• Long-term reliability compared to PVC or standard rubber

Inner Sheath

• Rubber compound GM1b

Functions include:

• Mechanical bedding

• Moisture barrier

• Additional protection during handling and lowering

Outer Sheath

The outer sheath is critical for survival in harsh environments:

• Chlorinated rubber compounds

  5GM5 for 0.6/1 kV (NSSHOEU)

  5GM3 for 1.8/3 kV and 3.6/6 kV (NTSWOEU)

Key properties:

• Oil resistance

• Abrasion and tear resistance

• Flame retardancy

• Long service life in submerged and contaminated conditions

Voltage Ratings and Cable Types Explained

NSSHOEU 0.6/1 kV

Best suited for:

• Low-voltage industrial pumps

• Municipal water systems

• Short to medium cable runs

Advantages:

• Cost-effective

• High flexibility

• Proven reliability in submerged LV applications

NTSWOEU 1.8/3 kV

Designed for:

• Deeper wells

• Higher motor outputs

• Reduced current and voltage drop

Provides:

• Improved insulation thickness

• Enhanced electrical performance

• Better efficiency for medium-depth installations

NTSWOEU 3.6/6 kV

The premium solution for:

• Large submersible pumps

• Deep mining shafts

• Long-distance underwater power transmission

Key benefits:

• Lower operating current

• Reduced conductor size for equivalent power

• Superior long-term reliability in demanding mining environments

Electrical and Mechanical Performance Parameters

Key performance characteristics include:

• Rated voltage and test voltage compliance

• Optimised current-carrying capacity under water

• Continuous operating temperatures suitable for EPR insulation

• Resistance to tensile and bending stresses during installation and retrieval

Dimensions, Weight, and Installation Considerations

Diameter and Weight Impact

Cable diameter and weight influence:

• Borehole sizing

• Suspension loads

• Installation equipment selection

For example:

• NTSWOEU 3×95 mm² 6 kV cable weighs approximately 5,870 kg/km, requiring careful load calculations.

Core Configurations

Common configurations include:

• 3-core designs

• 4-core designs where required

• Special sizes such as 3×70/35 mm²

Practical Installation Tips

• Avoid sharp edges during lowering

• Use proper strain relief systems

• Ensure compatibility with pump motors and rising mains

• Prevent torsional stress during installation

South African Case Study: Mining Dewatering in the North West Province

Project Background:
A platinum mine in South Africa’s North West Province required a reliable dewatering system for a deep underground section with continuous water ingress.

Challenges:

• Permanent submersion

• Oil-contaminated water

• High mechanical stress

• 24/7 operation

Solution:
Installation of NTSWOEU 3.6/6 kV submersible cables powering high-capacity pumps.

Results:

• Significant reduction in unplanned downtime

• Improved electrical stability

• Service life exceeding previous standard cable installations

• Lower total life-cycle cost

Comparison with Conventional Power Cables

Standard PVC or non-submersible rubber cables typically fail due to:

• Water ingress

• Insulation degradation

• Mechanical damage

NSSHOEU / NTSWOEU cables offer:

• Purpose-built underwater performance

• Superior durability

• Lower maintenance and replacement costs

Common Questions About NSSHOEU / NTSWOEU Submersible Cables (FAQ)

Q1: Can these cables operate continuously under water?
Yes, they are designed for permanent immersion.

Q2: Are they suitable for mining applications?
Absolutely, especially mine dewatering systems.

Q3: Why EPR insulation?
Because of its electrical stability, heat resistance, and longevity.

Q4: Can the rising pipe act as earth?
Yes, in approved installations.

Q5: Expected service life?
Typically many years under correct installation and loading.

Q6: How do I choose voltage rating?
Match motor rating, depth, and cable length.

Key Selection Guidelines for Engineers and Project Managers

• Match cable voltage to motor voltage

• Consider depth, temperature, and chemical exposure

• Ensure compliance with standards and project specs

• Factor in installation and life-cycle costs

Conclusion

In South Africa’s water and mining sectors, submersible cables are not consumables—they are critical infrastructure.

NSSHOEU and NTSWOEU submersible cables up to 6 kV offer:

• Proven electrical reliability

• Robust mechanical design

• Long service life in harsh submerged conditions

Choosing the right cable ensures:

• Safer operations

• Reduced downtime

• Lower long-term costs

• Confidence below the surface, where failure is not an option

Contact Anhui Feichun Special Cable Co., Ltd.

For comprehensive technical specifications and quotations, please contact our specialized mining cable engineering team:

Technical Engineering Support:

tech@feichuncables.com

Sales Engineering Department:

Li.wang@feichuncables.com

WhatsApp Contact:

Manufacturer: Anhui Feichun Special Cable Co., Ltd. (安徽飞纯特种电缆有限公司)

Manufacturing Headquarters: Building A, Private Science and Technology Park, Hefei Economic and Technological Development Zone, Anhui Province, People’s Republic of China

+86 17333223430