There appears to be a trend developing. Your insurance underwriter is asking you to provide an annual thermographic switchboard inspection, and for a lot of building managers and business owners this is the first time anyone has asked for one.
It is worth understanding why they are asking, because the request is not arbitrary and the report they will accept is more specific than most people expect.
Why underwriters started asking
Electrical fires in commercial buildings very rarely begin with a dramatic event. They begin with a connection that is not quite tight enough, or a component that has degraded, drawing the same current through a slightly higher resistance. That resistance turns current into heat. The heat degrades the termination a little further, which raises the resistance, which makes more heat.
The process is slow, silent, and completely invisible with the covers on. By the time it announces itself, the surrounding insulation has usually been cooking for months.
Insurers pay for the outcome. They have worked out that an annual infrared survey is a cheap way to intercept the process while it is still a maintenance item rather than a claim.
What "an inspection" actually means to them
This is where most requests come unstuck. An underwriter asking for a thermographic inspection is asking for a document with specific properties, not a site visit.
The report needs to identify:
- Every board inspected, by name and location, so the survey's coverage is defined
- The measured temperature at each anomaly, and the temperature of a reference component doing identical work
- The difference between them, because a single temperature means nothing on its own
- A priority rating against published criteria, with a stated repair timeframe
- The load at the time of inspection, because a fault under light load under-reads
- Who carried it out, and to what certification
If a report does not contain measurements, it is a set of photographs. Increasingly, underwriters know the difference.
The load condition matters more than people realise
A fault only generates heat when current flows through it. Inspect a board sitting idle and a serious defect can read completely normal.
The working standard is that boards must be live and carrying at least 40% of normal operating load during the survey. This is also why the inspection is non-intrusive: nothing is switched off, and the plant keeps running while the survey happens. The only interruption is that covers come off and go back on, which on most commercial boards is a job for your electrician.
If someone offers to inspect your switchboards during a shutdown, they are offering you a document, not an inspection.
Who is qualified to classify a finding
Capturing a thermal image is not difficult. Deciding what it means is the qualified part.
A Category 2 thermographer certified to ISO 18436-7 is trained to set and apply severity criteria, correct for emissivity and reflected temperature, and understand where a measurement is unreliable. A Category 1 holder can capture images competently; classification is a Category 2 function.
Ask for the certification number. It is a reasonable question and any legitimate provider will give it to you without hesitation.
What can make the number wrong
Even with the right equipment, several things will produce a reading that is confidently incorrect:
- Emissivity error. Bare copper and polished metal emit infrared very poorly. An uncorrected reading on a shiny busbar can be out by tens of degrees — always low, which is the dangerous direction.
- Reflection. Polished surfaces mirror the thermographer, the lighting and the surroundings, producing hot spots that are not there.
- Spatial resolution. If the target is physically smaller than the camera's measurement spot, the reading averages it with everything around it. Again, always low.
- Load. Covered above, and the most common reason a real fault is missed.
None of these are exotic. They are the everyday reasons an inspection carried out by someone without training produces a clean report on a board that is about to fail.
What it costs, and what it is worth
A single main switchboard survey with a full written report is a few hundred dollars. Distribution boards on the same visit are a fraction of that again.
Set against that: a burnt board replacement, an unplanned outage while it happens, and — if the failure causes a fire — an insurance conversation you would rather not have with a renewal condition unmet.
If you want to put your own numbers to it, the cost of late detection calculator prices the same defect at four points on its way to failure using your own repair and downtime figures.
What to do when the request lands
- Ask the underwriter for the condition in writing, so you know exactly what has to be produced and by when.
- Get a scope: how many main switchboards, how many distribution boards, and where they are.
- Confirm the provider is certified to ISO 18436-7 Category 2 and will supply the certification number.
- Book it while the site is running normally, not during a shutdown.
- Confirm who removes covers — your site electrical team if you have one, otherwise we bring an electrician.
- Diarise it annually — the second survey is where trending starts, and trending is what turns a report into a maintenance programme.
We carry out these inspections across the Sunshine Coast, Brisbane and throughout Queensland, and the report is written to be handed straight to your insurer. Details of the service and what a finding looks like are on the electrical thermography page.