What an IR Scan Actually Catches — And What It Misses

What thermography is actually good at

Infrared thermography catches loose, high-resistance connections before they fail. A bolt that should be torqued to spec but only got finger-tight will run noticeably hotter than its neighbors under load — and the difference is visible on the camera the moment you point it at the bus. That's the entire game: spot the outlier, schedule the fix during the next outage window, prevent the morning the burned lug takes out the floor. Across our active maintenance accounts, that's what we find over and over.

What thermography actually finds

Across the IR scans we run on commercial switchgear, panels, and MCCs every quarter, the recurring high-priority findings break down into the same handful of categories: loose lugs at panelboard or switchgear bus connections, failing breakers running hot at the bus stab, overloaded conductors on tenant feeders, and imbalanced three-phase loads that burn a single conductor harder than its mates. Every one of those becomes an outage within months if it isn't caught. A scheduled scan that catches one is almost always cheaper than the failure it would have produced — typically by an order of magnitude when you include service-interruption cost.

What thermography misses

An IR camera doesn't see voltage. It sees temperature. So it misses three categories of fault we get called for routinely: insulation breakdown that hasn't started arcing, neutral-to-ground bonds that have lifted, and motor windings degrading internally. For those we still pull a meter — insulation-resistance testing on motor circuits and feeders, neutral-ground voltage measurement at panels, and motor-circuit analysis where the load justifies it. The combination is the answer; IR alone is half the test.

Loading discipline (the boring requirement)

Thermography is meaningless on an unloaded panel. A breaker carrying a sliver of its rating won't tell you anything. Best practice is significant load at the time of scan — typically 40%+ of rated — and you have to confirm that with a clamp meter, not a guess. We schedule scans during peak operating hours — for offices that's mid-morning Monday–Thursday; for retail it's weekend evenings; for industrial it's production shifts. A scan done at 6 AM Sunday is documentation, not testing.

What goes in the report

Every IR finding gets four things in the report: thermal image, visible-light image of the same gear, delta-T reading versus reference, and a prioritized action (immediate, next-outage, monitor). The report goes to the facility lead with photos numbered to match a panel schedule, so the electrician dispatched to fix it walks straight to the right breaker. No 'check panel L2 area' notes — every finding has a panel number, circuit number, and a photo with an arrow.

IR is the cheapest insurance in the commercial electrical world — if you do it right. Done wrong (unloaded panels, no reference images, generic findings), it's a checkbox exercise that catches nothing. The difference is loading discipline, written reporting, and pairing the camera with a meter for the things thermography can't see.