Key takeaways
- An infrared thermography electrical inspection finds connections and components running hotter than they should, while the equipment is carrying its normal load.
- The scan only means something under load, so it is scheduled for a normal working day, with panels opened safely by a qualified electrician.
- A good report shows each finding with a thermal image, a regular photo, the location and a recommended action, ranked by urgency.
- The value is in the follow-up: every hot spot should be repaired and then scanned again to confirm the heat is gone.
An infrared thermography electrical inspection uses a thermal camera to look at panels, switchgear, disconnects and connections while they are working. Electrical problems that are on their way to a failure usually show up as heat first. A connection that has worked loose, a breaker carrying more than it should, or a conductor that is undersized for its load all run warmer than the equipment around them. The camera makes that heat visible, so it can be fixed on a planned day instead of during a shutdown nobody chose.
This guide covers what the inspection involves, what the camera can and cannot see, how to read the report, and what should happen after it. It is written for building owners, facility managers and property managers in the San Antonio area who are deciding whether a scan belongs in their maintenance plan.
Why heat is the early warning
Current flowing through any connection produces some heat. A tight, clean connection with the right size conductor produces very little, and it stays steady. When a connection loosens, corrodes or is overloaded, resistance goes up and so does the heat. That heat makes the problem worse over time: metal expands and contracts, the connection loosens further, insulation dries out, and eventually something fails or burns.
Most of that happens behind a closed panel cover, where nobody sees it. A thermal image catches it while it is still a maintenance item rather than an outage, a fire risk or a damaged piece of equipment.
What the scan looks at
An inspection is planned around the equipment that carries the building's load. On a typical commercial property that list includes:
- The main service equipment and the main disconnect.
- Distribution panels and the panels that feed tenant spaces.
- Breakers, fuses and the lugs where conductors land.
- Disconnects for rooftop units, compressors, pumps and other motor loads.
- Transformers and the connections on both sides of them.
- Busway, bus plugs and the connections at the ends of feeders.
- Motor control equipment on properties that have it.
The camera compares like with like. Three phases of the same circuit should run at about the same temperature, and identical breakers carrying similar loads should look similar. When one phase or one connection stands out from its neighbors, that difference is what the inspector writes up.
It only works under load
A scan of equipment that is lightly loaded tells you very little, because a bad connection carrying almost no current barely warms up. That is why the inspection is scheduled during normal operating hours, when the HVAC is running, the kitchen or production line is working and the building is drawing what it usually draws.
Seeing inside a panel also means removing covers on energized equipment. That is work for a qualified electrician wearing the right protective equipment and following the facility's safety procedures. Nobody should be pulling dead fronts off live panels to take a picture. Some properties have infrared windows installed on switchgear so the camera can see in without opening anything, which is worth considering on larger equipment that is scanned regularly.
What the camera cannot tell you
Infrared is a strong tool with real limits, and a good inspector will tell you what they are. The camera sees surface temperature. It cannot see through a closed metal cover, and shiny surfaces such as bare bus or polished metal reflect heat from other objects, which can hide a problem or invent one that is not there. A component that only fails under a load the building did not carry that day will not show up.
A scan also does not replace the rest of maintenance. Tightening, cleaning, exercising breakers and testing protective devices are separate tasks. NFPA 70B, the standard for electrical equipment maintenance, treats thermography as one part of an overall maintenance program rather than the whole of it, and that is the right way to think about it.
How to read the report
The report is the product you are paying for, so it should be easy to act on. Each finding should include:
- The equipment and its location, named the way your building names it.
- A thermal image and a regular photo of the same spot, so the repair crew can find it.
- The temperature of the problem compared with a similar reference, such as the other phases.
- The likely cause, such as a loose connection or an overloaded circuit.
- A recommended action and how soon it should happen.
Findings are usually ranked by severity, so you know what needs attention now and what can wait for the next planned shutdown. A list of every panel scanned with no problem found is useful too, because it shows the inspection actually covered the equipment it claims to.
After the scan: the repairs
Thermography finds problems; it does not fix them. Most hot spots are repaired by de-energizing the equipment, cleaning and remaking the connection, replacing a damaged lug or breaker, or rebalancing loads that have drifted onto one phase. Some repairs need a planned outage, which in an occupied building is scheduled after hours or on a weekend.
At Wattsmith, every repair from a report gets a written price before the work is done, and we schedule outages around your hours. Once a repair is complete, the spot should be scanned again under load to confirm the heat is gone. Repairs that grow into larger work, such as a panel that cannot carry its load, are covered on our panel upgrade service page and in our guide to a commercial electrical service upgrade.
How often to scan
Many facilities scan once a year, and properties with heavy, steady loads or equipment that cannot be allowed to fail often scan more often. Insurance carriers sometimes ask for a scan as part of their own review. The right interval depends on the building, the age and condition of the equipment, and what an unplanned outage would cost the business. The first scan is often the most useful, because it gives you a baseline to compare every later scan against.
We cover how scans fit into a full maintenance plan in our post on commercial electrical preventive maintenance and infrared scans. On our maintenance agreements, infrared scans of loaded equipment are part of the scheduled visits, with a written condition report after each one.
Getting started
Before a first inspection, gather what you have: the panel schedules, any single line drawing, and a list of equipment that has given trouble. Pick a normal working day for the scan, and let tenants or staff know which panels will be opened. Plan for a short follow-up window for repairs, since it is common for a first scan to find something worth tightening.
It also helps to decide in advance who receives the report and who approves the repairs. On a multi-tenant property, a finding inside a tenant's panel may be the tenant's responsibility under the lease, while the house panels and the service belong to the owner. Sorting that out before the scan keeps the follow-up from stalling while people work out who pays. Keep each year's report with the building's records, because the comparison from one scan to the next is where slow changes show up.
For everything else we do for businesses, see our commercial electrical services page. If a scan turns up a problem that needs attention right away, our commercial electrical repair guide explains what happens from the call to the fix.