Severity Isn’t a Color — It’s a Defensible Decision
In professional electrical thermography, the most valuable skill isn’t finding a hot spot — it’s translating temperature data into a consistent, repeatable severity decision that supports electrical maintenance best practices and electrical safety expectations.
What Is Thermography Severity?
Thermography severity begins by selecting a valid comparison method, calculating the temperature difference (ΔT), and then applying the applicable ANSI/NETA MTS suggested-action tier. In the CTE™ Program, colors are only a visual teaching aid mapped to that tier — they are not an independent thermography standard.
Why Severity Matters in the CTE™ Program
A defensible thermography program uses a defined comparison method and documented ΔT so findings can be communicated consistently without inventing a separate severity scale.
ANSI/NETA MTS supplies the suggested-action framework used for the CTE™ visual mapping, NFPA 70B supplies the electrical maintenance context, and NFPA 70E governs electrical safety-related work practices. These roles should not be blended together.
Severity protects you professionally: it creates a defensible, repeatable method rather than “it looked hot.”
Severity Is the Bridge Between Thermography and Reliability
A thermal camera doesn’t “diagnose” a problem — it reveals thermal behavior. A defensible finding comes from identifying the correct comparison, calculating ΔT, applying the applicable ANSI/NETA MTS suggested-action tier, and then documenting the other evidence that affects the final professional recommendation. The CTE™ color is only a visual representation of that NETA tier.
ΔT is meaningful only when the reference is valid. A similar-component comparison and a component-to-ambient comparison are not interchangeable because ANSI/NETA MTS assigns different action thresholds to them. Absolute temperature, manufacturer limits, equipment ratings, load, environment, and historical trend remain important evidence, but they are evaluated separately rather than used to invent a different CTE color.
Where NFPA 70B and NFPA 70E Fit in a Thermography Program
Thermography sits at the intersection of maintenance and electrical safety, but the documents serve different roles. NFPA 70B addresses electrical equipment maintenance and recognizes infrared thermography using temperature-difference comparisons. ANSI/NETA MTS provides the suggested-action tiers used for the CTE™ color mapping. NFPA 70E addresses electrical safety-related work practices, including the controls required when a task exposes a worker to electrical hazards.
Thermography is part of an electrical maintenance program. Document the comparison basis, ΔT, loading information, equipment condition, and other relevant evidence so the finding can support a maintenance decision rather than a color-only conclusion.
Electrical safety requirements are determined by the task and the electrical hazards involved — not by a Green, Yellow, Orange, or Red thermography label. A thermal severity result never overrides the electrical safety program or NFPA 70E work practices.
Important reminder
Thermography must be planned and performed in accordance with the organization’s electrical safety program and applicable NFPA 70E work practices. A severity result is never permission to move closer, remove a barrier, cross a boundary, or perform energized work without the required justification and controls.
The Big 6: What Affects Confidence and the Professional Recommendation
Heating is load-dependent. Document loading and whether the compared components were operating under sufficiently similar conditions. Load affects confidence in the comparison and the recommendation; it does not create a different NETA color threshold.
First establish whether the finding is based on similar components under similar loading or component-to-ambient. Do not mix the two threshold columns. If the comparison is weak, document that limitation rather than forcing a severity result.
Shiny or low-emissivity surfaces can produce misleading apparent temperatures. Manage emissivity and reflected apparent temperature appropriately and document material limitations.
Airflow, wind, covers, enclosure heat soak, and ventilation can change the observed thermal pattern. These conditions belong in the interpretation and report.
Confirm that the target adequately fills the measurement spot and that viewing angle and distance do not compromise the reading. Measurement quality affects confidence in ΔT.
Historical trend, manufacturer limits, equipment ratings, thermal pattern, asset criticality, and other evidence can materially affect the professional recommendation. They should be documented separately and do not independently recolor the measured NETA tier.
Making Severity Actionable: What Your Report Must Include
A color without the comparison basis is not a defensible thermography finding. A CTE-quality report should make the comparison method, measured ΔT, applicable ANSI/NETA MTS tier, CTE visual color, supporting evidence, and professional recommendation clear enough that another qualified person can follow the logic.
CTE™ reporting checklist (no fluff)
Include asset identification and location, circuit loading and operating context when available, the qualifying comparison method (similar components under similar loading or component-to-ambient), measured and reference temperatures, calculated ΔT, the applicable ANSI/NETA MTS suggested-action tier, the corresponding CTE™ visual color, thermal and visual images, measurement limitations, manufacturer or equipment temperature limits when relevant, historical trend when available, and the final professional recommendation. Trending is supporting evidence — not a third NETA comparison column.
Severity and the “False Alarm” Problem
One of the fastest ways to lose trust in a thermography program is to let color replace the actual comparison method. Over-calling a finding can create alarm fatigue and waste maintenance resources; under-calling can allow a deficiency to continue. The CTE™ colors exist only to make the applicable ANSI/NETA MTS action tier easier for students and report readers to recognize.
For the applicable NETA comparison, Green maps to the first suggested-action tier: a possible deficiency that warrants investigation. Do not convert Green into a universal “no problem” label.
Yellow corresponds to the NETA tier indicating a probable deficiency with repair as time permits. The exact ΔT range depends on whether the comparison is similar-component or component-to-ambient.
Orange maps only to the 21–40°C component-to-ambient tier, where the suggested action is to monitor until corrective measures can be accomplished. There is no Orange tier for similar components under similar loading.
Red corresponds to >15°C for similar components under similar loading or >40°C for component-to-ambient. The NETA suggested action is immediate repair; the work itself must still be planned and performed under the applicable electrical safety requirements.
The CTE™ Method: Repeatable, Defensible, Teachable
The Certified Thermal Electrician™ Program does not create a competing thermography standard. It teaches technicians to establish the correct comparison, calculate ΔT correctly, apply the applicable ANSI/NETA MTS suggested-action tier, document the maintenance context required by NFPA 70B, follow NFPA 70E electrical safety-related work practices, and then use CTE™ colors only as a clear visual aid. The technical logic comes first; the color comes last.
Professional note: This article is educational and supports thermography decision-making. It is not a substitute for ANSI/NETA MTS, NFPA 70B, NFPA 70E, your organization’s electrical safety and maintenance programs, site-specific procedures, manufacturer instructions, or an engineering evaluation where one is required.
