⚡ The Critical Role of Emissivity in Electrical Thermal Imaging — And How to Adjust It on the Mileseey TR20 Pro

Thermal imaging has become a core diagnostic tool for electricians, facility maintenance teams, and predictive maintenance professionals. But even the most advanced thermal cameras are only as accurate as the settings used to operate them—especially when scanning electrical components such as breakers, lugs, busbars, terminals, conductors, motor leads, or metallic enclosures.

One setting stands above all others in determining whether a temperature reading is trustworthy or misleading: emissivity.

Understanding emissivity is essential for any electrician performing thermography, and it is one of the first concepts taught in the Certified Thermal Electrician™ Program. Because electrical surfaces vary widely in reflectivity, thermal conductivity, and radiative behavior, emissivity adjustments are not optional—they are fundamental.

This is also why our partnership with Mileseey Tools is so valuable. Their TR20 Pro thermal imager provides electricians with a powerful, intuitive way to control emissivity settings, helping ensure accurate temperature readings in the field.

🔥 What Is Emissivity and Why Does It Matter?

Emissivity is a measure of how effectively a surface emits infrared radiation compared to a perfect emitter (called a “blackbody”). Emissivity values range from 0.00 to 1.00.

High-emissivity surfaces (typically 0.85–0.95) include painted metal, insulation, rubber, and many oxidized surfaces. Low-emissivity surfaces (often 0.10–0.30) include bare copper, bare aluminum, stainless steel, and polished metals.

Low-emissivity surfaces reflect infrared radiation rather than emitting it. This means the camera may display:

• The temperature of surrounding objects.
• The temperature of the technician or nearby equipment.
• Ambient reflections from walls, lighting, or hot equipment.
• False “hot spots” or misleading cool areas.

For electrical thermography, that can lead to dangerous misinterpretations.

For example, a bare copper lug may be 160°F internally, but due to low emissivity, the camera displays 110°F. Without adjusting emissivity or compensating with proper technique, the true failure point is hidden.

For this reason, emissivity is one of the most critical concepts electricians must master when performing thermal imaging.

⚡ Electrical Components Are Not “Thermal-Friendly” Surfaces

Electrical systems contain many low-emissivity metals—exactly the surfaces most likely to develop dangerous heat:

• Circuit breaker terminals and lugs.
• Aluminum wire terminations and busbars.
• Bus duct joints and stabs.
• Transformer taps and terminations.
• Motor peckerheads and terminal blocks.
• Bare conductors and metallic straps.
• Switchgear stabs and metallic enclosures.

These components often appear cooler than they truly are unless emissivity is properly accounted for. This is why using a camera with adjustable emissivity—such as the TR20 Pro from Mileseey Tools—is essential.

🎛️ Adjusting Emissivity on the Mileseey TR20 Pro

Our partner Mileseey Tools has given electrical professionals a major advantage by making emissivity adjustments fast, intuitive, and field-friendly on the TR20 Pro thermal imager.

1. Access the Emissivity Setting

On the TR20 Pro:

• Press the Menu button.
• Navigate to Settings.
• Select the Emissivity (ε) option.

The default emissivity is often set around 0.95, which is correct for many non-metal, matte surfaces—but incorrect for most bare electrical metals.

2. Choose the Correct Emissivity Value

When scanning electrical systems, approximate emissivity values are:

• Bare copper: 0.20–0.30
• Oxidized copper: 0.65–0.85
• Bare aluminum: 0.10–0.30
• Painted metal: 0.90–0.95
• Rubber insulation: ~0.95
• Many plastics: ~0.95

The TR20 Pro allows you to manually set emissivity to match the observed surface, dramatically increasing measurement accuracy.

3. Apply a High-Emissivity Target When Needed

If the metal is too reflective, electricians can improve accuracy by applying a small high-emissivity reference spot on the surface, such as:

• A small piece of standard electrical tape.
• A dot of flat, non-reflective paint (when equipment is de-energized and permitted).
• A high-emissivity sticker designed for thermography.

Once placed, you adjust the emissivity on the TR20 Pro to match the tape or coating. The camera then gives a more realistic temperature reading of that point, acting as a reliable reference.

4. Re-Scan the Component After Adjustments

Once emissivity is set correctly and any necessary high-emissivity markers are in place:

• The apparent temperature rises to more closely reflect the true thermal load.
• Hot spots become clearer and easier to quantify.
• Subtle phase-to-phase or component-to-component differences are easier to see.
• Reflections and false patterns are greatly reduced.
• Diagnostic accuracy increases significantly.

This is vital when identifying loose connections, over-torqued lugs, corrosion, phase imbalance, or load-driven heating in electrical systems.

⚠️ Why Emissivity Errors Are Dangerous in Electrical Work

Improper emissivity settings can lead to:

• Underestimating dangerous temperatures: low-emissivity surfaces may hide hotspots that are 20–50°F hotter than displayed.
• Drawing incorrect conclusions: a seemingly cool terminal may actually be failing internally.
• Misdiagnosing phase imbalances: one phase may appear hotter just because of surface differences, not actual load.
• False confidence in equipment safety: high-risk components may appear normal.
• Inaccurate NFPA 70B maintenance reports: emissivity errors can invalidate thermal criteria and trending data.

This is why all Certified Thermal Electrician™ students study emissivity in depth—and why tools from Mileseey Tools, particularly the TR20 Pro, are an excellent match for electrical thermography.

🤝 Mileseey Tools and the Certified Thermal Electrician™ Program

Our partnership with Mileseey Tools ensures that Certified Thermal Electricians have access to thermal imagers that:

• Support precise, adjustable emissivity control.
• Provide stable, repeatable temperature readings.
• Offer high-resolution imaging for electrical diagnostics.
• Remain affordable for contractors entering the thermography market.
• Use intuitive menus to reduce operator error in the field.

The TR20 Pro in particular is ideal for electrical work because it combines adjustable emissivity, excellent image clarity, a strong refresh rate, and user-friendly controls—everything a Certified Thermal Electrician™ needs on a live job.

When paired with the Certified Thermal Electrician™ training, electricians gain both the theoretical knowledge and practical technique needed to use emissivity correctly in every scan.

🎓 Conclusion: Emissivity Is the Foundation of Electrical Thermography

Electrical thermography is only as accurate as your understanding and application of emissivity. Whether scanning switchgear, panelboards, transformers, MCCs, bus ducts, or motor circuits, emissivity determines whether your camera reveals the truth—or hides it.

Thanks to Mileseey Tools and the advanced capabilities of the TR20 Pro, electricians now have a powerful, affordable device that makes emissivity adjustment simple and reliable.

For those who want to master emissivity interpretation, diagnostic technique, and real-world thermography for electrical systems, the Certified Thermal Electrician™ Program provides the only training of its kind designed specifically for electricians.