Thermal Imaging for Electricians: Why the Mileseey TR20 Pro & TR384C Are Strong Choices for the Certified Thermal Electrician™ Program
Thermal imaging has become an important condition-assessment tool in the electrical industry. As electricians work with increasingly complex systems—including switchgear, data centers, motors, HVAC systems, UPS equipment, transformers, and renewable-energy systems—the ability to identify abnormal thermal patterns while equipment is operating can provide valuable information before visible damage or failure occurs.
Inside the Certified Thermal Electrician™ (CTE™) Program at ThermalElectrician.com, two Mileseey thermal cameras provide useful options for electrical thermography:
- Mileseey TR20 Pro – 320×240 infrared resolution with a 50 Hz frame rate, well suited for general field inspections and everyday electrical troubleshooting.
- Mileseey TR384C – 384×288 infrared resolution with a 25 Hz frame rate, providing additional detector resolution for detailed inspection and documentation.
Either camera can be useful when its resolution, field of view, measurement capability, and other specifications are appropriate for the target and inspection conditions. The camera itself does not determine whether a thermographic inspection is valid—the inspection method and the thermographer do.
1. Why Temperature Analysis Matters in Electrical Systems
Many electrical problems produce abnormal heating before visible damage occurs. Increased connection resistance, excessive loading, load imbalance, harmonic current, deteriorating contacts, cooling problems, and other conditions can create thermal patterns that warrant further investigation.
The TR20 Pro and TR384C can help electricians identify those thermal patterns so the condition can be evaluated before it progresses.
✔ Identify Unexpected Thermal Conditions
Thermal imaging can help reveal:
- Unexpected conductor or cable heating
- Abnormal transformer thermal patterns
- Overheating electrical components in HVAC equipment
- UPS battery or connection temperature irregularities
- Asymmetric thermal patterns between phases
- Localized termination or connection heating
These findings can identify areas that deserve electrical testing, inspection, maintenance, or continued observation.
✔ Support Quality Control
In installation, maintenance, and commissioning environments, thermography can provide additional condition information by revealing:
- Localized heating at electrical terminations
- Unexpected breaker or bus-connection temperatures
- Uneven thermal patterns associated with load distribution
- Temperature differences between comparable components
- Changes following corrective maintenance
Thermography cannot prove that a termination was properly torqued or that equipment was installed correctly simply because the temperature appears normal. Those conditions must be verified using the appropriate electrical and mechanical procedures.
✔ Support Electrical Fire-Prevention Programs
Excessive electrical heating can contribute to insulation damage, connection deterioration, equipment failure, and fire hazards. Routine thermographic inspections performed within an appropriate electrical maintenance program can help identify abnormal thermal conditions before significant damage develops.
2. TR20 Pro & TR384C for Electrical Thermography
Mileseey TR20 Pro – The Everyday Workhorse
The TR20 Pro currently provides:
- 320×240 infrared resolution
- 50 Hz frame rate for smooth live imaging
- ≤40 mK thermal sensitivity
- 50° × 37.2° field of view
- Adjustable emissivity
- Center, hot-spot, and cold-spot measurement tools
- Visible-light camera and multiple image modes
- Image and video recording
- PC analysis software support
Its wide field of view and 50 Hz frame rate can make it useful for general electrical inspections where the target is adequately resolved at the working distance.
Mileseey TR384C – Higher Detector Resolution
The TR384C currently provides:
- 384×288 infrared resolution
- 25 Hz frame rate
- ≤40 mK thermal sensitivity
- 28° × 21° field of view
- Adjustable emissivity
- Center, hot-spot, cold-spot, and multi-area measurement tools
- GPS
- Laser distance measurement
- Wi-Fi connectivity
- Visible-light camera
- PC analysis software support
The higher detector resolution and narrower field of view can place more detector pixels on a smaller target at a given distance than a lower-resolution, wider-angle camera. Whether that produces a valid quantitative measurement still depends on target size, distance, focus, emissivity, reflections, and the camera's practical measurement field of view.
3. Best Practices for Electrical Thermography
✔ Set the Measurement Parameters Correctly
Use the camera manufacturer's instructions to establish the appropriate measurement parameters. Depending on the camera and inspection, these can include:
- Emissivity
- Reflected apparent temperature
- Object distance
- Atmospheric parameters when applicable
- Temperature range
- IR-window or external-optics parameters when applicable
Palette selection changes how the image is displayed but does not change the underlying radiometric temperature data.
✔ Account for Environmental and Surface Variables
Reflected radiation, airflow, solar loading, ambient conditions, viewing angle, target emissivity, distance, focus, and target size can influence the usefulness of a thermal measurement and must be considered when they are relevant.
✔ Inspect Under Representative Operating Load
Electrical thermography is most useful when equipment is operating under a load that meaningfully represents its normal operating condition.
NFPA 70B annex guidance discusses circuit loading of not less than 40% of nominal circuit loading when normal circuit loading is not feasible. That 40% value should not be treated as a universal threshold that automatically makes every scan valid or invalid. Actual circuit loading and relevant operating conditions should be documented when they affect interpretation.
✔ Use Maintenance-Program Inspection Intervals
There is no universal rule stating that motors and MCCs must be scanned monthly, switchgear biannually, and an entire facility annually.
Thermographic inspection intervals should be established through the applicable electrical maintenance program and should consider:
- NFPA 70B equipment-condition assessment
- Equipment condition and maintenance history
- Manufacturer recommendations
- Asset criticality
- Previous thermographic findings
- Operating environment
- Facility reliability requirements
- Applicable governing or contractual requirements
✔ Follow Electrical Safety Requirements
A thermal camera is noncontact, but the work required to obtain line of sight to energized electrical equipment can create electrical exposure. Follow the employer or facility electrical safety program and applicable NFPA 70E requirements based on the actual task, equipment condition, shock hazard, arc-flash hazard, boundaries, and work method.
PPE is not determined by the CTE™ color or the apparent severity of a thermal finding.
✔ Get Proper Electrical Thermography Training
The Certified Thermal Electrician™ Program trains electricians to apply thermography within an electrical context, including electrical heating principles, measurement variables, comparison methods, NFPA 70B maintenance concepts, ANSI/NETA MTS suggested-action criteria, reporting, and electrical safety considerations.
4. Choosing Between the TR20 Pro and TR384C
Detector Resolution
Field of View
- TR20 Pro: 50° × 37.2° — wider field of view.
- TR384C: 28° × 21° — narrower field of view.
These differences affect how much of the scene is captured and how many detector pixels can be placed on a particular target at a given distance.
Refresh Rate
- TR20 Pro: 50 Hz
- TR384C: 25 Hz
Refresh rate primarily affects how smoothly motion is displayed. It should not be used by itself to determine which camera will produce the better quantitative temperature measurement.
Measurement & Reporting
Either camera can support professional electrical thermography when used within its specifications and when the target is adequately resolved.
The CTE™ reporting framework should document information such as:
- Equipment and asset identification
- Thermal and visual images
- Operating/load condition
- Target temperature
- Reference temperature
- Calculated ΔT
- Comparison method
- Measurement limitations
- Applicable ANSI/NETA MTS suggested-action tier
- Professional recommendation
5. The CTE™ Framework: Measurement First, Classification Second
A thermal camera does not assign the severity of an electrical condition simply because a particular temperature appears on the screen.
First establish whether the measurement itself is valid. Then determine the correct thermographic comparison:
- Similar electrical components under similar loading
- Electrical component compared with ambient air temperature
Once the correct comparison has been established, the applicable ANSI/NETA MTS suggested-action criteria can be applied to the resulting ΔT.
6. Conclusion: The Camera Is Only Part of Electrical Thermography
Thermal imaging can provide electricians with valuable information about electrical equipment while it is operating. The Mileseey TR20 Pro and Mileseey TR384C provide two different combinations of resolution, field of view, frame rate, and features that can be useful for electrical inspections.
But professional electrical thermography is not defined by the camera. It depends on the thermographer's understanding of infrared measurement, electrical systems, loading, comparison methods, equipment behavior, electrical safety, documentation, and the limits of what the thermal image can actually prove.
The Certified Thermal Electrician™ Program at ThermalElectrician.com is designed specifically to bring those disciplines together so electricians can use thermal imaging as a defensible electrical condition-assessment tool.
👉 Learn more or enroll at: ThermalElectrician.com
Educational note: Always follow the thermal-camera manufacturer's specifications and instructions, the employer or facility electrical safety program, applicable NFPA 70E work practices, NFPA 70B maintenance requirements, ANSI/NETA criteria when used by the maintenance program, equipment manufacturer instructions, and site-specific requirements.
