Most electrical fires in industrial switchgear do not begin with a bang. They begin with a connection that was a quarter turn loose, or a lug that corroded, or a cable that was sized for a load the panel no longer carries. Resistance rises at that one point. Current passing through it turns into heat. The heat oxidises the contact, which raises resistance further, which makes more heat. The process is slow, self-reinforcing, and completely invisible behind a closed panel door.
The window you actually have
That runaway takes weeks or months. For most of it, the fault is nothing more than a warm spot — twenty or thirty degrees above the terminals beside it, carrying load normally, tripping nothing. A protective device will not act, because nothing is faulted yet. The only thing distinguishing that terminal from its neighbours is temperature.
Infrared thermography reads that difference through a survey that takes minutes per panel, with the equipment running and under load. It does not require a shutdown, which is the usual reason electrical inspection gets postponed.
What a survey finds
- Loose or under-torqued connections, the single most common finding, and usually a ten-minute fix.
- Corroded terminations, particularly in coastal and humid environments.
- Load imbalance across phases, which shows as one phase consistently hotter than the other two.
- Overloaded conductors and breakers running hot against their rating.
- Failing contactors, where the contacts have pitted and no longer close cleanly.
The part people get wrong
A thermographic image is not self-explanatory. A hot spot means something only in comparison — against the identical terminal on the next phase, against the same panel last quarter, against the load it is carrying at that moment. A reading taken at twenty percent load will understate a fault that only shows at full load. A survey without load data, reference images and a severity criterion is a folder of orange pictures, not an inspection.
What makes it useful is the report: this terminal, this many degrees above its reference, at this load, in this severity class, fix it within this period. That is something a maintenance planner can act on.
Why it is worth the hour
The fix for almost everything found is tightening a connection or replacing a lug. The cost of not finding it is a burnt panel, an unplanned outage, and in the worst case a fire in a space people work in. Few inspections have that ratio between effort and consequence.
When Was Your Switchgear Last Surveyed Under Load?
Our inspection team runs infrared thermographic surveys of electrical panels, switchgear and motor control centres while they are running, and reports findings by severity with the load they were taken at.
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