Cable monitoring is crucial for the reliable and efficient transmission and distribution of electricity. Industries often overlook power cables in daily operations, yet these critical assets can develop hidden hotspots that pose serious risks. If neglected, these localized hotspots can escalate to widespread outages, triggering safety risks, regulatory non-compliance, and millions in downtime losses.

According to the Electric Power Research Institute (EPRI), power cable failure rates are between 0.7 and 2 failures /100 miles /year. The majority of these are due to avoidable causes, such as mechanical stress, electrical overloads, and installation errors. Traditional inspections usually fall short, particularly for underground installations where visual inspections are not possible. Thereby, the challenge is not cable, but the absence of continuous condition monitoring.

That’s why utilities and industries are moving toward advanced cable monitoring technologies to prevent cable failure. An advanced monitoring system not only responds to defects, they enables predictive maintenance and minimizes unexpected outages.

In this blog, we will explore what cable hotspots are, where they typically form, why cable monitoring is important, and how it is changing the way businesses secure their assets.

How Cable Monitoring Can Safeguard Your Critical Components from Hotspots?

A cable hotspot is a localized region where the temperature increases significantly beyond normal operating conditions. It is not the same as usual heating caused by routine current flow, but hotspots form due to exposure, such as poor connections, insulation damage, or mechanical stress at specific points. These occurrences appear at the system’s weakest points.

Where Do Cable Hotspots Typically Form?

1. Cable Joints and Terminations: Improper installation, poor connector crimps, broken stud in bushing well, or moisture ingress can create high-resistance zones, leading to overheating.
2. Bends and Tight Routing Areas: Excessive bending stresses the conductor, and delamination on the conductor causes uneven current distribution and thermal accumulation.
3. Insulation Zones: Water treeing, abrasion, and voids, contaminations weaken insulation, cracking of embrittled insulation, and aging /overall degradation accelerate thermal runaway.
4. Conductor Shields (Semicon Layers): Overheating or protrusions on semicon layers can lead to arcing and dielectric failure.
5. Metallic Shield / Neutral Faults: Damage or improper shield can result in localized current concentration, increasing temperature.

Additional risks include third-party damage, such as excavation or rodent infestations, as well as installation errors resulting from poor workmanship or failure to follow manufacturer guidelines, which may occur during operation or maintenance. Thus, there is a growing need for cable monitoring to mitigate these risks before they result in catastrophic failure.

Key Risks of Ignoring Cable Hotspots

• Unexpected Downtime: Abrupt cable failure can shut down the production line or trigger blackouts in critical buildings, resulting in costly downtime.
• Safety Hazard: Overheated cables may ignite fires, arc flash events, or expose live conductors, putting maintenance teams and surrounding infrastructure at risk.
• High Repair Costs: Emergency repairs and cable replacements are far more expensive than scheduled maintenance, since they require skilled technicians and may necessitate temporary shutdowns.
• Shorten Asset Life: Continuous thermal stress reduces the operational life of power cables and associated systems, raising the rate of failures.
• Regulatory Non-Compliance: In industries where reliability standards are required, failures can result in penalties, audits, or loss of certifications.
• Reputation Damage: Frequent outages and safety issues mean loss of customer trust, impacting long-term business credibility.

This is where reactive strategies transition to predictive maintenance, enabling the prevention of cable failures and the implementation of advanced cable monitoring.

What if a hotspot in a critical underground cable went unnoticed until failure?

For instance, an underground power cable in a refinery is developing a hotspot at a joint. Initially, it will not be noticeable since no alarms, no visible smoke. Gradually, over weeks, the heat slowly degrades the insulation. By the time the issue becomes critical, causing failure, the result is not just a single outage. The entire feeder line trip, production halts, and restarting operations take several days.

The Financial Damage? Millions in downtime and emergency repair costs, all this because of a lack of safety and environmental risk.

Such situations are not rare. In fact, some studies indicate that over 70% of high-voltage and medium-voltage cable failures are attributed to hotspots, partial discharge, or insulation breakdown. The irony is that all these failures were preventable with continuous power cable monitoring. However, utilities and industries overlooked these risks and suffered the consequences.

How Cable Hotspot Detection Strengthens Predictive Cable Monitoring

The methods used to detect hotspots using cable monitoring are similar to those applied in temperature monitoring. Distributed temperature sensing (DTS) embeds fiber optic cables along or within power cables. They function as continuous thermal sensors, measuring temperature variations in real-time. Rather than waiting for failure to occur, operators receive a real-time heat map of cable health, pinpointing hotspots and ensuring predictive maintenance.

Why Industries Trust Fiber Optic Hotspot Detection

• Immune to electromagnetic interference.
• Detects minor changes across the entire cable length, not just sample points.
• Works in extreme or high-voltage environments, and their non-conductive nature makes them intrinsically safe.
• Easily integrates into IIoT monitoring platforms, enabling remote oversight.
• Compact, lightweight, and robust design makes it easy to integrate into complex structure.

Benefits of Cable Monitoring Across Various Sectors

Power cables are an integral component of modern electrical infrastructure, quietly transmitting electricity where it’s needed the most. As demand grows and the challenges of an aging grid increase, the risk for cable fault detection gets higher. Cable monitoring is no longer restricted to utilities only -it’s revolutionizing reliability in various industries.

1. Urban Infrastructure & Smart Grids

Electric utilities face increasing loads due to urbanization and the integration of renewable energy sources. One undetected hotspot in a feeder cable can initiate cascading outages, impacting thousands of customers.

Benefits: Cable monitoring enhances grid robustness, enables quicker underground cable fault detection, and avoids blackouts before they occur.

2. Industrial Facilities

Factories and refineries depend on continuous power. Cable failure not only cause downtime but also a standstill in manufacturing process, risks personnel safety and resulting in lost income.

Benefits: Power cable strategies avoid downtime, protect production assets, and enable scheduled shutdowns with predictive maintenance.

3. Renewable Energy Systems

Renewable energy systems such as solar plants and wind farms rely on underground and subsea cables. Cable failures have consequences that are expensive and tricky to repair at offshore and remote solar farms.

Benefits: Cable monitoring enables the detection of issues in extreme environments, preventing prolonged outages and costly repairs.

4. Transportation & Mobility

Electrified railways, metros, and EV charging stations are critically dependent on cables. Cable failures here can interfere with passenger services and mobility networks, causing chaos to routine.

Benefits: Real-time cable monitoring ensures uninterrupted access to transit systems, enhancing public trust and safety.

5. Critical Infrastructure (Hospitals, Data Centers, Airports)

Critical sectors operate continuously with no room for disruption. Patient care, vast amounts of sensitive data, and passenger services all depend on uninterrupted network connectivity.

Benefits: Cable monitoring enables public safety, economic stability, and resilience through its reliable operations.

Cable hotspots may initiate as tiny, invisible voids, but their impact on the grid can be catastrophic. The future lies in smarter cable monitoring, which adheres to predictive, proactive maintenance and is built to minimize escalation of cable failure and breakdown. In the next blog, we will explore how fiber optic technology is revolutionizing cable monitoring.