Infrared Thermography Basics: How Heat Patterns Catch Electrical and Mechanical Failures Cheap

Key takeaways

• Infrared thermography = imaging the heat signatures of equipment to detect electrical and mechanical failures.
• Catches loose connections, overloaded circuits, bearing degradation, refractory damage, insulation failures.
• Cheap per inspection (handheld camera); high ROI on electrical and rotating equipment.
• Needs trained operator to interpret images correctly.
• Best paired with vibration (rotating) and ultrasonic (leaks) for comprehensive condition monitoring.

Short answer: Infrared thermography images the heat signatures of equipment to detect electrical and mechanical failures before they cause breakdowns. It catches loose connections, overloaded circuits, bearing degradation, refractory damage, and insulation failures cheaply. Handheld cameras cost a few thousand euros; trained operators interpret images and create the value. Best deployed alongside vibration analysis for rotating equipment. See also Vibration Analysis Basics.

What thermography detects

Electrical:

• Loose connections (heat from resistance).
• Overloaded circuits (excessive current).
• Phase imbalance (one phase hotter).
• Failed capacitors.
• Hot fuses or breakers.

Mechanical:

• Bearing degradation (friction heat).
• Coupling misalignment (heat at misaligned interface).
• Brake drag.
• Lubrication failure.

Thermal insulation:

• Refractory damage in furnaces.
• Insulation failure on pipes.
• Building envelope heat loss.

How it works

All objects emit infrared radiation proportional to their temperature. A thermographic camera images this radiation as a temperature map.

Healthy equipment has expected thermal patterns. Failures change the pattern — hot spots, temperature differences between phases, abnormal gradients.

When to use it

• Electrical inspection. Annual or semi-annual sweep of switchgear, panels, motors.
• Building envelope. Energy auditing.
• Refractory monitoring. Furnaces, kilns, melters.
• Bearing screening. Walk-around supplement to vibration.
• Process equipment. Heat exchangers, steam traps, insulation.

What thermography misses

• Internal defects without heat signature.
• Failures that develop too fast for periodic inspection.
• Issues hidden behind covers or in enclosed cabinets (unless windows are installed).

Pair with other methods: vibration for rotating, ultrasonic for leaks.

Camera specifications that matter

• Resolution. Higher resolution catches smaller hot spots. 320x240 minimum for industrial; 640x480 for detail.
• Thermal sensitivity. NETD (Noise Equivalent Temperature Difference). Lower is better; 50 mK industrial standard.
• Temperature range. Match to expected operating temperatures.
• Spot size. Field of view determines smallest detectable feature.

Consumer cameras are usually inadequate; industrial cameras start in the few-thousand-euro range.

Common analysis patterns

Loose connection: single hot terminal vs adjacent normal ones.

Phase imbalance: one phase consistently hotter than the other two.

Overload: entire breaker hotter than peers.

Bearing failure: bearing hotter than housing average.

Insulation failure: cold spot on hot pipe or hot spot on cold storage.

Severity classification

Common five-level system:

• Level 1: investigate, monitor.
• Level 2: schedule maintenance.
• Level 3: maintenance soon.
• Level 4: immediate maintenance.
• Level 5: emergency.

Based on temperature delta vs reference and consequences of failure.

Common mistakes

1. Reading the wrong emissivity. Different materials emit differently; misinterpretation produces wrong conclusions.

2. Inspecting under no load. Electrical issues only appear under load.

3. Untrained operator. Camera is easy; interpretation is hard.

4. No baseline. Comparing to historical thermal images catches degradation early.

5. No follow-up. Findings logged; nobody acts.

Cost considerations

• Camera: €2,000-15,000 depending on resolution and sensitivity.
• Training: Level 1 thermographer certification is a few-day course.
• Inspection time: minutes per asset for a trained operator.

ROI is typically fast on electrical inspection alone.

Common mistakes

1. Treating thermography as the whole condition monitoring program. Pair with vibration and ultrasonic.

2. One-time inspection. Periodic sweeps catch degradation; one-time misses development.

3. No CMMS integration. Findings disconnected from work order workflow.

How OEE relates

Catches electrical issues before they produce unplanned downtime. Plants with mature thermography programs see Availability move up as electrical issues become planned response.

How a modern CMMS supports thermography

A modern CMMS integrates thermography findings into asset history, generates WOs on severity-3+ findings, and tracks recurring issues across assets.

Fabrico's CMMS integrates thermography findings into asset history and generates condition-based WOs.

See how Fabrico captures this automatically — explore OEE for manufacturing or book a demo.

Related reading

• Vibration Analysis Basics

Frequently asked questions

How often should I do thermal inspection?

Electrical annually or semi-annually; rotating equipment as a vibration supplement.

Can a consumer camera work?

No. Industrial inspection needs resolution and sensitivity that consumer cameras lack.

Do I need certification?

Level 1 thermographer certification is common practice; some industries require it.

Can thermography replace vibration analysis?

No. They catch different failures. Use both.

What is the most-found issue?

Loose electrical connections. Common, cheap to fix, high consequence if missed.