Electrical thermography benefits insurance companies for a straightforward reason: it identifies electrical problems before they become claims.
That is the short version. The longer version explains why the request has become so common, and why the report you supply has to meet a standard that a set of photographs will not.
The risk being mitigated
Faulty electrical equipment and wiring remain among the most common causes of fire in commercial and industrial buildings. The failure pattern is consistent enough to be predictable.
A termination loosens, or a component degrades. Resistance rises. The same current now generates heat where it previously did not. That heat degrades the connection further, raising resistance again. The process compounds quietly behind a closed cover, sometimes for years.
From an underwriter's position this is close to the ideal insurable hazard to attack: high consequence, low visibility, slow onset, and cheap to detect if anyone bothers to look.
Why infrared specifically
Several things make thermography unusually well suited to the insurer's problem:
- It works on live plant. No outage means no commercial reason to defer the inspection, which means it actually happens.
- It is non-contact. The survey introduces no new risk to the equipment being inspected.
- It produces measurements. A temperature difference is evidence, and evidence is what an underwriter can price.
- It is repeatable. The same survey next year is directly comparable, so deterioration is visible.
- It is cheap relative to the exposure. A few hundred dollars per board against a total loss.
What the insurer actually wants in the report
This is where requests commonly fail. "We had it thermally imaged" does not satisfy a condition if what was produced is a folder of orange pictures.
A report that will be accepted identifies:
- Every board and asset inspected, by name and location
- The measured temperature at each anomaly
- The temperature of a reference component doing identical work under the same load
- The difference between them, which is the actual finding
- A priority rating against published criteria, with a repair timeframe
- The load at the time of inspection
- The thermographer's certification
The load condition is not a technicality. A fault only produces heat when current flows through it, so a survey carried out on lightly loaded or idle boards can return a clean report on equipment that is genuinely failing. The working requirement is at least 40% of normal operating load.
The severity criteria
Findings are classified rather than described, which is what makes one report comparable with the next:
| Priority | ΔT vs reference | Fault temperature | Recommended action |
|---|---|---|---|
| 1 — Critical | > 30 °C | > 100 °C | Serious abnormality. Immediate repair recommended — failure may be imminent. |
| 2 — Significant | 20 – 30 °C | 75 – 100 °C | Should be corrected — could fail suddenly. Repair within one week. |
| 3 — Caution | 10 – 20 °C | 50 – 75 °C | Minor problem. Rectify when convenient, then re-inspect for the trend. |
| 4 — Checked | < 10 °C | < 50 °C | No abnormality at inspection. Re-inspect at regular intervals. |
A Priority 1 finding with a documented repair afterwards is a strong position at renewal. A Priority 1 finding with no follow-up is a worse position than never having inspected at all, because the risk is now documented and unaddressed. That is worth understanding before commissioning a survey: the report creates an obligation as well as a defence.
Who is qualified to classify
Setting and applying severity criteria is a Category 2 function under ISO 18436-7. A Category 1 holder is trained to capture images competently; classification, emissivity correction and judging when a measurement cannot be trusted sit at Category 2.
Ask for the certification number. Any legitimate provider will give it without hesitation, and some underwriters now ask for it directly.
What it is worth in practice
The commercial case rarely needs much construction. Set the cost of an annual survey against a burnt board, the unplanned outage while it is replaced, the after-hours premium because these things never fail on a Tuesday morning, and the excess on a fire claim.
If you would rather see it in your own numbers than take the general argument, the cost of late detection calculator prices one defect at four points on its way to failure using your repair cost, downtime rate and hours lost.
For what a survey involves and what a real finding looks like, see the electrical thermography page. If your underwriter has already sent the condition, what they will and will not accept is covered in more detail.