What Causes Underground Power Cable Short Circuits?

Underground power cables are designed to deliver safe and reliable electricity, but over time they can develop faults. One of the most common and disruptive issues is a short circuit. When this occurs, the power supply is interrupted, equipment may malfunction, and safety risks increase especially in commercial and residential areas. Understanding the main causes behind underground cable short circuits helps prevent outages and ensures quicker rectification.

Understanding the causes of underground power cable short circuits helps prevent outages and ensures faster rectification when problems arise.

1. Aging and Deterioration of Cable Insulation

Over time, underground cables naturally degrade due to heat, moisture, soil pressure, and environmental conditions. As insulation becomes weak or brittle, the conductors can come into contact with each other or with the earth, leading to a short circuit. Underground cables degrade naturally due to heat, moisture, and soil pressure. As insulation weakens, conductors may come into contact with each other, causing a short circuit. Regular cable testing helps identify early insulation damage.

2. Poor Installation Practices

Incorrect cable laying, improper jointing, or using substandard materials can cause premature failure. Common installation issues include:

• Sharp bends in the cable
• Incorrect burial depth
• Poorly installed joints or terminations
• Insufficient protection during backfilling

These problems can create points of stress that eventually lead to insulation damage and short circuits.

3. External Mechanical Damage

External forces are one of the leading causes of underground cable faults. Typical sources include:

• Excavation and digging works
• Heavy vehicle movement over shallow-buried cables
• Construction equipment striking the cable

Even minor mechanical damage can weaken insulation and cause a delayed short circuit.

4. Water Ingress and Moisture

Moisture entering cable joints, terminations, or damaged insulation can reduce insulation resistance. Over time, this leads to:

• Corrosion of conductors
• Breakdown of insulation
• High leakage currents that result in a short circuit

In areas with high groundwater levels, water ingress becomes a significant risk.

5. Rodent or Pest Damage

Rodents sometimes chew through cable insulation, particularly in older or poorly protected installations. When insulation is eaten away, conductors become exposed, resulting in earth faults or short circuits.

6. Overloading and Overheating

If a cable carries more current than it is designed for, the conductor temperature rises. Continuous overheating accelerates insulation breakdown. Once insulation weakens enough, a short circuit can occur between phases or phase-to-earth.

7. Soil Movement & Environmental Stress

Shifting soil, especially in areas with:

• Heavy rains
• Construction activity
• Vibrations
• Thermal expansion

can cause mechanical stress on underground cables. This movement may crush or stretch cables, damaging insulation and causing a fault.

Professional Cable Fault Detection & Rectification

When a short circuit occurs, fast and accurate fault locating is essential. At ControlTek Electro Mechanical, we use advanced testing equipment and cable route tracing technology to pinpoint underground cable faults with precision. Our team provides: we use advanced technologies for accurate cable fault location including:

• Cable route tracing
• Fault location
• Cable jointing and rectification
• Testing and commissioning

Conclusion

ControlTek is a well-experienced company with a professional team ready for 24/7 emergency underground cable fault rectification. For immediate assistance, please contact +971 50 369 0890.