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Electrical infrared thermography: delta T severity of a hot spot

Classify an electrical hot spot from its temperature difference with a similar component or the ambient air (NETA MTS), and get the repair urgency. Free.

  • Instant result
  • Formula and standards shown
  • On desktop and phone

Pre-filled example

One phase of a circuit breaker 12 °C hotter than the other two, circuit loaded at 60%.

°C
%

Result

Probable deficiencySeverity

Action
Repair as time permits
Attach this calculation to a work order

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Each hot spot turned into a dated work order

Here, the calculator is free and the result is gone when you close the page. In Reglova, it is attached to the work order on the right machine: you find it again at the next breakdown, and on audit day.

The CMMS software comparison, our gaps included
  • Attached to the work order with its inputs: the server recalculates it, it stays verifiable.
  • On the technician's phone, even without a network.
  • In the machine's history, for the next breakdown.
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Reglova · Calculations · Work order WO-AT01-04219
Silent video, 33 s: from the work order for an oil leak on a shear cylinder, the tightening torque of an M12 bolt, then "Attach to the work order". A step to tighten it to 93.1 N·m lands in the checklist (step text from the French demo data). Watch the video

When to classify a thermography hot spot

  1. 01

    Sort the hot spots of a thermography survey before opening work orders.

  2. 02

    Set the repair deadline for a connection that heats up.

  3. 03

    Keep the same grid from one survey to the next to compare.

Good to know

Below 40% load, the difference is underestimated because it grows with current: measure again at full load if possible. Check the grid's wording against the 2023 edition of NETA MTS.

NETA delta T thresholds for electrical hot spots

In infrared thermography of a panel or a switchboard, what matters is not the temperature of a point but its difference from a similar component under the same load, or from the ambient air. The calculator classifies the difference with the NETA MTS thresholds and gives the corresponding action.

Formula · Reference documents

Similar components: 1 to 3 °C possible, 4 to 15 probable, over 15 major ; ambient air: 1 to 10 possible, 11 to 20 probable, 21 to 40 monitor, over 40 major

NETA MTS, table 100.18 (wording to be checked against the 2023 edition)

Inputs and accepted ranges
InputUnitAccepted rangeExample
Measured difference2 optionsBetween similar components
Temperature difference ΔT°C0 to 1,00012 °C
Circuit load%0 to 20060 %
Calculated results
  • Severity
  • Action
What the calculator flags
  • Load below 40 %: the difference grows with load, the class is underestimated.

Thermography surveys followed to the last repair

  • Breakdowns reported by QR code
  • Work orders on the phone, even without a network
  • Mandatory inspections reminded by email
  • Audit file as a PDF, in one click
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Free during the beta, no credit card