Thermographic cameras are valuable tools for electrical inspection.

They help identify heat patterns that may point to loose connections, overloaded circuits, failing breakers, transformer issues, phase imbalance, poor terminations, motor problems and other developing faults.

The main advantage is that many inspections can be performed while equipment is operating under load. That means a facility can often inspect critical systems without stopping production.

But good thermal images do not happen automatically.

A thermal camera only shows the surface temperature pattern it can detect. If the equipment is not loaded, the emissivity is wrong, the angle is poor, the surface is reflective, the distance is too great, or the inspection is done without the right safety plan, the result can be misleading.

The original JM Test article makes this point through electrical examples: thermal cameras work best when electrical systems are running under normal load, when the user understands emissivity, and when hot or cold differences are interpreted in context rather than treated as automatic proof of failure. 

For Canadian teams, electrical thermography should also be planned around CSA Z462-informed safe work practices, qualified worker requirements, shock and arc-flash risk assessment, equipment condition, site procedures and the applicable federal, provincial or territorial safety requirements. CSA Z462:24 sets requirements and guidance for workplace electrical safety, including safe work procedures, PPE selection, qualified worker criteria and energized electrical equipment hazards. 

Why Electrical Systems Should Be Under Load

Thermal cameras detect heat patterns.

For electrical inspections, heat usually appears when current is flowing.

If a panel, breaker, conductor, transformer or motor is not carrying meaningful load, a developing issue may not show clearly. A loose connection or overloaded conductor may look normal if there is not enough current flowing during the inspection.

The source article says electrical systems should be running at normal load and recommends no less than 40% of maximum load capacity, with full load being better where practical. 

In practical terms, thermal inspections are more useful when:

• The equipment is operating under normal conditions.
• Loads are stable enough to compare phases or similar components.
• The inspection record includes approximate load condition.
• The thermographer understands what the system was doing at the time.
• Follow-up images are taken under similar conditions where possible.

A thermal image without load context can be hard to interpret later.

Electrical Safety Comes First

Thermography can reduce downtime, but it does not remove electrical risk.

If the inspection involves energized electrical equipment, open panels, exposed conductors or approach boundaries, the work must be planned carefully.

CCOHS explains that arc flash risk assessment should identify arc flash hazards, determine likelihood and possible injury severity, and decide the protective measures needed, including PPE. CCOHS also defines the arc flash boundary as the distance where a person without PPE may receive a second-degree burn if an arc flash occurs. 

Before performing electrical thermography, confirm:

• Whether the equipment can remain closed
• Whether an IR window is available
• Whether a cover or door must be opened
• Whether energized conductors or parts are exposed
• Whether the worker may cross a limited or restricted approach boundary
• Whether the worker may be inside the arc flash boundary
• Whether the thermographer is qualified for the task
• Whether an escort is required
• Whether PPE is required
• Whether the equipment is in normal operating condition
• Whether the inspection increases the likelihood of an arc flash event
• Whether a permit, authorization or pre-job briefing is required

Do not use a fixed distance such as “four feet away” as a universal safety rule. Working distance depends on the equipment, voltage, exposure, shock boundary, arc flash boundary, incident energy, task and site procedure.

Emissivity: The Biggest Source of Bad Temperature Readings

Emissivity describes how well a surface emits infrared energy.

Thermal cameras do not measure temperature directly in the way a contact probe does. They interpret infrared radiation coming from a surface. FLIR states that thermal camera measurement accuracy depends on factors such as distance, ambient temperature and the emissivity of the material being observed. 

A high-emissivity surface is easier to measure accurately.

A low-emissivity surface is harder to measure accurately because it may reflect heat from nearby objects, including the thermographer, sun, sky, equipment or other heat sources.

The source JM Test article notes that reflective surfaces such as aluminium, stainless steel, copper, chrome and nickel are harder to measure accurately, while painted surfaces, rubber and ceramics are generally easier. 

FLIR also warns that glossy or reflective metals tend to be poor emitters, and reflected temperature can affect the temperature a thermal camera measures.

Reflective Surfaces Can Trick the Camera

A shiny metal surface may look hot because it is reflecting something hot.

Or it may look cooler than expected because of the way it reflects the surrounding environment.

That does not always mean the component itself is at that temperature.

FLIR gives a practical example: an object can be cool to the touch but appear hotter in the thermal image if it reflects a nearby heat source. FLIR also notes that if accurate temperature measurement is important on difficult surfaces, training is needed to correctly compensate for emissivity and reflected temperature. 

For electrical inspection, be careful with:

• Bare copper
• Aluminium bus
• Stainless steel
• Polished metal
• Chrome
• Nickel-plated parts
• Shiny labels
• Clean metallic fittings
• Glass or plastic covers
• Reflective panel surfaces

A thermal image should be interpreted with surface condition in mind.

How to Improve Readings on Low-Emissivity Surfaces

When temperature accuracy matters, a thermographer may need to increase or standardize the target emissivity.

Common methods include:

• Measuring a painted, oxidized or non-reflective area
• Using approved high-emissivity tape where safe and allowed
• Using a known high-emissivity target
• Avoiding direct reflections
• Adjusting emissivity settings
• Adjusting reflected apparent temperature settings
• Comparing similar materials under similar conditions
• Taking images from a suitable angle
• Recording the camera settings used

FLIR states that high-emissivity surfaces such as electrical tape can be used to measure low-emissivity surfaces like shiny metal more accurately. 

For energized electrical equipment, do not add tape, paint or any material unless the equipment condition, safety procedure and qualified worker assessment allow it. A measurement trick should never create a safety hazard.

Breaker Panels and Electrical Panels

Thermal cameras are often used to inspect breakers, panels and terminations.

A hot breaker does not always mean the same thing.

The source article explains that if the heat signature travels up the wire feeding the breaker, the issue may be load-related. If the heat is isolated to the breaker itself, the breaker may be failing or already defective. 

During panel inspections, look for:

• Hot breakers
• Hot lugs
• Heat at wire terminations
• Phase imbalance
• Overloaded conductors
• Poor contact points
• Loose connections
• Hot neutral conductors
• Abnormal fuse heating
• Uneven heating between similar components
• Components that are unexpectedly cool compared with active neighbours

A thermal image should lead to verification, not guesswork.

Follow-up may include load measurement, voltage checks, current measurement, torque verification where permitted, resistance testing, power quality analysis or planned repair under an approved electrical safety procedure.

Why Follow-Up Images Matter

A thermal image before repair is useful.

A thermal image after repair is often just as important.

The source article recommends photographing the breaker after the repair to confirm that the correct item was fixed and the system is now operating properly. 

After a repair, record:

• The same equipment ID
• Similar load conditions where practical
• Before and after images
• Current or load readings
• Ambient condition
• Date and time
• Repair performed
• Person responsible
• Follow-up recommendation

This creates a stronger maintenance record and helps avoid repeated troubleshooting.

Transformer Inspections

Thermal cameras are often used around transformers.

Depending on the transformer type and inspection access, thermography may help identify:

• Hot bushings
• Loose connections
• Load imbalance
• Cooling problems
• Poor terminations
• Abnormal tank heating
• Fan or cooling system issues
• Blocked airflow
• External hot spots
• Internal cooling concerns where visible indicators exist

The source article notes that transformer overheating may be linked to loose connections, excessive load, or cooling issues, and that oil-filled transformers rely on oil to help cool internal coils. 

Do not assume a thermal image alone diagnoses the full transformer condition.

Follow-up may require electrical testing, oil testing, load review, inspection of cooling equipment, bushing inspection, dissolved gas analysis, manufacturer guidance or engineering review.

A faulty transformer can be urgent, but the corrective action should be based on the asset, symptoms, test results and risk.

Overloaded Circuits and Conductors

Thermal cameras are useful for finding overloaded circuits, but they must be used with care.

Overheated conductors may indicate:

• Excess current
• Loose terminations
• Undersized conductors
• Poor contact
• Unbalanced loads
• Harmonics
• Poor ventilation
• Environmental heat
• Failing breaker or fuse holder
• Deteriorated insulation
• Installation issues

The source article explains that overstressed breakers and overheating conductors are common faults, and that excess current or wasted current often appears as heat. 

A thermal image can tell you where to look.

It does not automatically tell you why the heating is happening.

Use the thermal finding as the start of troubleshooting, not the end.

Three-Phase Imbalance

Thermal imaging can help identify imbalance in three-phase systems.

If one phase is hotter than the others, that phase may be carrying more load, have a poor connection, or be affected by a downstream issue.

If one phase is much cooler than the others, it may be lightly loaded, disconnected, failed, open, or not carrying current when it should be.

The source article notes that both unusually hot and unusually cool components can be important, and that harmonics can also contribute to three-phase imbalance. It recommends using a power analyzer when the exact cause needs to be confirmed. 

For three-phase systems, compare:

• Similar conductors
• Similar phases
• Similar breaker poles
• Similar fuse holders
• Similar terminals
• Similar load paths
• Similar operating conditions

Do not compare unrelated components and assume the temperature difference means failure.

Hot Does Not Always Mean Bad, and Cool Does Not Always Mean Good

A common thermography mistake is looking only for hot spots.

Hot spots matter, but cool spots can matter too.

The source article explains that a component showing cooler than its counterparts may not be working at all or may not be carrying load. 

Examples:

• A cool fuse may be open.
• A cool phase may not be carrying current.
• A cool breaker may feed an inactive load.
• A cool motor starter may not be energized.
• A hot breaker may be overloaded.
• A hot termination may be loose.
• A hot conductor may be carrying excess current.

Temperature difference must be interpreted against the circuit, load and equipment function.

Thermal Cameras Cannot See Through Walls

Thermal cameras detect surface temperature patterns.

They do not see through walls, clothing, panels or solid objects.

The source article explains that a camera can show heat transferred to the surface in front of the lens, such as a wall surface affected by a warm pipe, but it cannot see the pipe itself if the heat signature is not transferred to the visible surface. 

This matters in building, mechanical and electrical troubleshooting.

A thermal image may show a pattern on a surface.

The actual source may be behind it, below it, above it or unrelated.

Verification is still needed.

Distance, Focus and Image Quality

Better thermal results depend on better image quality.

FLIR states that thermal camera measurement accuracy depends on distance from the object, ambient temperature and emissivity. 

Before taking the image, check:

• Is the target in focus?
• Is the distance reasonable?
• Is the target large enough in the frame?
• Is the correct temperature span used?
• Is the emissivity setting appropriate?
• Is there reflected heat?
• Is the viewing angle acceptable?
• Is the target under normal load?
• Is the image radiometric if later analysis is needed?
• Are visible and thermal images paired where helpful?
• Is the asset ID documented?

A blurry thermal image may still look impressive, but it may not support a good maintenance decision.

Camera Selection Matters

The right thermal camera depends on the job.

For electrical thermography, consider:

• IR resolution
• Thermal sensitivity
• Focus type
• Lens options
• Temperature range
• Accuracy
• Emissivity adjustment
• Image storage
• Reporting software
• Battery life
• Screen visibility
• Safety and ruggedness
• Wireless or meter integration
• Ability to capture radiometric images
• Compatibility with IR windows where applicable

The FLIR T530, mentioned in the source article, has 320 × 240 IR resolution, or 76,800 pixels, and FLIR lists accuracy as ±2°C or ±2% of reading, with variable emissivity correction and temperature ranges up to 650°C standard, with an optional range up to 1200°C depending on configuration. 

For Canadian publishing, keep availability conditional. JM Test Canada lists thermal imagers and IR thermometers, including FLIR, Fluke, Fotric and SEEK options, and shows the FLIR T530 Professional Thermal Camera as a call-for-availability product. 

Thermal Camera Checklist for Electrical Inspections

Before the inspection:

• Confirm the inspection route.
• Confirm qualified worker requirements.
• Review arc flash labels and boundaries.
• Confirm required PPE.
• Confirm whether panels stay closed or are opened.
• Confirm IR window use where available.
• Confirm the equipment is operating under load.
• Confirm camera battery, memory and settings.
• Confirm emissivity assumptions.
• Confirm report format.

During the inspection:

• Stay outside unsafe approach boundaries.
• Use the safest practical working distance.
• Keep panels closed where possible.
• Avoid touching energized parts.
• Compare similar components under similar loads.
• Capture visible and thermal images where useful.
• Record load or current where possible.
• Note reflective surfaces.
• Do not over-interpret shiny metal readings.
• Stop if the equipment condition looks unsafe.

After the inspection:

• Prioritize findings by severity and risk.
• Verify with electrical measurements where needed.
• Document asset ID and location.
• Save original radiometric images where available.
• Take post-repair images.
• Trend repeated inspections over time.
• Update the maintenance record.

Where Thermal Cameras Are Useful

Electrical Panels

Thermal cameras can help identify hot breakers, poor terminations, overloaded circuits and abnormal heating.

Transformers

They can help identify external hot spots, bushing heating, cooling issues and abnormal thermal patterns.

Motors

Thermal imaging can help detect overheating, bearing issues, load problems, cooling issues and phase imbalance clues.

Fuses and Disconnects

Temperature differences can point to poor contact, overloaded circuits or a failed/open component.

Switchgear and MCCs

Thermography can help find loose joints, heating terminals, overloaded compartments and abnormal breaker or contactor heating.

Mechanical Systems

Thermal imaging can also support inspections of bearings, belts, pumps, insulation, pipes, steam systems, HVAC and process equipment.

The source article focuses heavily on electrical applications, including panels, breakers, transformers, overloaded circuits and three-phase imbalance. 

Common Thermography Mistakes

Inspecting Equipment With Too Little Load

If the system is not carrying enough load, faults may not show clearly.

Ignoring Emissivity

Reflective metal surfaces can produce misleading readings.

Treating Every Hot Spot as the Same Problem

Heat may come from load, poor contact, environment, reflection or component failure.

Ignoring Cool Components

Cool components may indicate an open circuit, failed component or unloaded phase.

Standing Too Close to Energized Equipment

Safety boundaries and PPE must be determined by the task and risk assessment, not convenience.

Not Taking Post-Repair Images

A repair should be confirmed and documented.

Assuming the Camera Sees Through Materials

Thermal cameras detect surface temperature patterns. They do not see through walls or panel covers.

Using the Wrong Camera for the Job

Resolution, focus, lens, measurement range and reporting features matter.

JM Test Systems Canada Support

JM Test Canada lists thermal imagers and IR thermometers in its Canadian product catalogue, with products from brands such as FLIR, Fluke, Fotric and SEEK. 

JM Test Canada’s rental page also says its rental division includes instrument and controls, electrical, communications, gas detection, utility products and mechanical equipment. For Canadian copy, do not copy the original US page’s Baton Rouge address, US phone number or US-specific distributor language without confirmation. Use Canadian availability language instead.

Customers should confirm:

• Thermal camera availability
• Rental or purchase options
• Camera resolution
• Lens options
• Temperature range
• Software/reporting tools
• Accessories
• Calibration or verification documentation
• Shipping timeline
• Suitability for electrical thermography
• Compatibility with IR windows where applicable

Practical Takeaway

A thermographic camera can help identify electrical and mechanical problems before they become failures.

But good results depend on more than pointing the camera at equipment.

The system should be under meaningful load. The thermographer must understand emissivity and reflection. Similar components should be compared under similar conditions. Hot and cool differences both matter. Follow-up measurements and post-repair images are important. Safety planning is essential around energized electrical equipment.

The source JM Test article correctly emphasizes load, emissivity, breaker patterns, transformer heating, overloaded circuits, three-phase imbalance, and the fact that thermal imagers do not see through walls or solid materials.

For Canadian teams, the best approach is to use thermal cameras as part of a planned inspection programme, supported by CSA Z462-informed electrical safety practices, proper PPE selection, qualified workers, documented findings and follow-up verification.