Top 3 Causes of Overheating in Electrical Panels and How to Stop Them

Top 3 Causes of Overheating in Electrical Panels and How to Detect Them

Imagine this: a large industrial plant suddenly loses an entire production line. When maintenance opens the breaker panel, they find a scorched busbar connection—a hot spot that had been quietly building heat for months. The last thermography inspection? It showed no problems at all.

Scenarios like this aren’t rare. Overheating inside electrical panels is a leading cause of unplanned downtime in both industrial facilities and data centers. The good news is that these failures are highly preventable if you know what to watch for and how to monitor them.

Let’s break down the top three causes of overheating and how continuous monitoring with the GraceSense Hot Spot Monitor (HSM) can help you catch issues before they turn into costly failures.

1. Loose Electrical Connections

Loose or improperly tightened electrical connections are the number one cause of overheating and electrical failures in panels. Over time, vibration and thermal expansion can loosen bolted connections (like lugs, screw terminals, busbar joints, etc.), increasing electrical resistance at that point. Higher resistance causes localized heating whenever current flows.

Loose connections alone contribute to over 30% of all electrical failures and are a major cause of power outages. As the connection degrades, it can start to arc or even glow red-hot from the concentrated heat, a clear precursor to failure or fire if left unaddressed.

Why it matters:

• Loose joints can glow red‑hot and lead to arcing or fires.
• They’re responsible for a large percentage of electrical failures.

How to catch it:

• Traditional method: quarterly or annual IR scans (good, but only a snapshot).
• A more effective method is to use permanently mounted sensors, such as the HSM, that continuously monitor critical connection points 24/7.
• HSM mounts to busbars, breaker lugs, and transformer connections without system modifications, and alerts you as soon as abnormal heat is detected.

2. Overloaded or Unbalanced Circuits

Electrical panels can also overheat when circuits are overloaded, carrying more current than they were designed for. Overload conditions often occur in facilities that add new equipment without balancing the load or upgrading the infrastructure. Drawing excessive current through a circuit causes wires, breakers, and bus connections to heat up beyond their normal operating temperature.

If one phase or branch circuit is consistently overloaded (or heavily unbalanced relative to others), that section of the panel will run hotter and put stress on components. Overloaded circuits not only risk tripping breakers; they can also bake insulation and loosen connections over time, compounding the overheating problem.

Warning signs:

• Warm panel surfaces or a “hot electrical” smell.
• Frequent breaker trips or nuisance shutdowns.

Why continuous monitoring helps:

• Overload conditions often happen during peak operations, when no one is scanning with an IR camera.
• HSM sensors detect rising temperatures in real-time and send an alert before a breaker fails or insulation breaks down.
• Over time, trend data helps you spot circuits that consistently run hotter than others.

3. Infrequent or Incomplete Thermography

Even when the equipment itself is in good shape, gaps in the monitoring process can lead to overheating issues going unnoticed. Many facilities rely on scheduled IR thermography surveys, typically conducted only once or twice a year, to identify hot spots within electrical panels. 

These routine inspections provide only a snapshot of the situation at a given moment. If a problem develops shortly after an inspection, it may be months before the next check catches it (if it’s caught at all). This infrequency makes thermography a hit-or-miss strategy for detecting progressive issues.

Furthermore, IR scans have practical limitations. They are typically performed under the prevailing load conditions at the time. If an inspection is conducted during a light load period or when certain equipment is offline, emerging hot spots under full-load conditions may be missed.

Some critical connection points might also be hidden from an IR camera’s line of sight, especially if you’re scanning through an IR window on the panel. IR viewing windows help improve safety by allowing you to inspect without opening the panel. However, they still offer a limited field of view, meaning a loose busbar bolt tucked behind a barrier could still escape detection.

And of course, performing “open-door” thermography (where you remove panel covers for a direct view) is hazardous and disruptive, requiring extensive PPE and often a shutdown. Due to these constraints, periodic thermography can miss intermittent or slowly-worsening heat issues, giving a false sense of security that “everything looks fine” when it isn’t.

While helpful, these inspections often:

• Miss issues that develop between scans.
• Are performed when equipment isn’t fully loaded, leading to false “all clear” readings.
• Only show what’s visible through an IR window—hidden connections can still overheat undetected.
• Require open-panel work if done without IR windows, increasing arc-flash risk and PPE requirements.

Why Continuous Thermal Monitoring (CTM) is better:

• Sensors continuously monitor key points under all load conditions.
• Progressive heating trends are detected long before failure.
• Meets NFPA 70B standards, allowing you to extend inspection intervals beyond one year while staying compliant.
• Keeps technicians out of energized panels, improving safety.

NFPA 70B and the Shift Toward Continuous Thermal Monitoring

This approach isn’t just a good idea—it’s quickly becoming the new standard in electrical maintenance. The NFPA 70B standard explicitly emphasizes the implementation of CTM as part of a proactive maintenance program. In other words, industry codes now recognize that always‑on temperature monitoring is critical for safety and reliability, not just an optional add‑on.

The HSM was designed with these standards in mind. It fully supports NFPA 70B compliance by:

• Continuously recording temperature data at critical bolted connections
• Providing automated alerts when abnormal heating is detected
• Allowing facilities to extend the time between manual inspections while staying within NFPA 70B guidelines.

By adopting continuous monitoring, you’re aligning with modern preventive maintenance practices and dramatically reducing the chance that a developing hot spot slips through the cracks.

Why GraceSense™ HSM Is Different

Electrical panel overheating doesn’t have to be an inevitable surprise. By understanding and addressing these top causes – loose connections, overloads, and insufficient monitoring – maintenance teams can greatly improve their facility’s electrical reliability.

The key is early detection. Each of these issues gives off warning heat signatures before they turn into major failures, and capturing those signs is now easier than ever with continuous monitoring technology.

Instead of periodic snapshots, you get a complete thermal picture of your switchgear, bus ducts, breaker panels, and transformers in real time. This not only prevents unplanned downtime by catching problems early, but also extends equipment life (since excessive heat is known to accelerate component aging).

• Fiber-optic sensors attach directly to critical bolted connections.
• Alerts flag issues in real time, giving you the chance to fix problems on your schedule.

By identifying loose connections, overloads, and hidden hot spots, HSM helps you prevent unplanned downtime, enhance safety, and meet modern NFPA 70B continuous thermal monitoring standards.

Take the Next Step

Don’t wait for a failure to find out where your panel is vulnerable. Learn how to detect hot spots before they cause downtime and get your copy of the GraceSense eBook here.