Infrared Thermography: Catching Electrical Failures Before They Happen

Electrical connections fail predictably. Resistance rises at a loose or corroded termination, resistance generates heat, heat accelerates oxidation, and oxidation raises resistance further. The loop runs until the connection opens, arcs, or ignites what is around it.

The useful part is that infrared thermography makes the loop visible long before it shows up in any other way. A thermographic survey turns an invisible degradation curve into a photograph with a temperature attached to it.

What a Thermographic Survey Covers

A commercial survey typically includes every point where current changes direction, changes conductor, or changes device:

• Main switchgear, main distribution panels, and branch panels
• Transformers and their primary and secondary terminations
• Motor control centers, starters, contactors, and variable frequency drives
• Disconnects, fused switches, and safety switches
• Automatic transfer switches and generator connections
• Bus duct, tap boxes, and large feeder terminations
• Rooftop mechanical equipment disconnects and whips

In many facilities the rooftop equipment produces the most findings, because it lives outdoors through Texas summers and winters and nobody opens it between service calls.

The Survey Has to Happen Under Load

This is the constraint that catches building owners by surprise. Infrared finds heat, and heat requires current. Scanning a panel serving equipment that is off tells you nothing.

A meaningful survey is scheduled when the building is running normally — ideally at or near peak operating load for the season. For an office, that is a weekday afternoon in summer with HVAC working. For a plant, it means production running. Coordinating that window is usually the hardest part of the job.

What the Findings Mean

Thermographers evaluate findings by comparing a component against its reference: the identical phase beside it, an identical device elsewhere, or the ambient environment. A single warm phase in a three-phase set is a far stronger signal than three warm phases, which may simply indicate a heavily loaded circuit doing exactly what it should.

Findings are usually prioritized roughly as

• Minor — a small rise above reference. Document, monitor, address at the next planned outage.
• Intermediate — a clear anomaly. Schedule a repair rather than waiting for the next annual cycle.
• Serious — significant rise with load. Repair at the next available window, and reduce load on that circuit if practical.
• Critical — severe heating. Address immediately; this is the condition that becomes an outage or a fire without warning, and it is a reason to call for emergency service rather than wait for the next maintenance window.

Exact temperature thresholds vary by standard, by equipment type, and by load at the time of the scan. What matters more than the number is that your report states the load condition, the reference used, and the rationale for the priority assigned. A report that shows a red picture with no context is a sales tool, not an inspection.

What a Usable Report Contains

• A thermal image and a matching visible-light image for every finding
• Equipment identification specific enough to find it again — room, panel, breaker position
• Measured temperature, reference temperature, and the delta
• Load condition at the time of the scan
• Probable cause and recommended corrective action
• A priority rating with the reasoning stated
• Areas that could not be surveyed, and why

That last line is the integrity check. Covers that could not be removed safely, equipment that was down during the visit, and enclosures with no viewing access are all legitimate gaps — but they belong in the report, not left implied.

How to Prepare Your Facility

1. Schedule during normal operation, at representative load.
2. Clear access to all electrical rooms and equipment — move storage in advance.
3. Have a maintenance escort available who knows the building and can authorize access.
4. Provide up-to-date panel schedules and single-line drawings if they exist.
5. Decide in advance who has authority to approve an immediate repair if a critical finding surfaces.

That last item prevents the common outcome where a critical finding sits in an inbox for three weeks waiting on an approval chain.

Where Thermography Fits in a Maintenance Program

An annual survey suits most commercial buildings. Facilities with critical uptime requirements, heavy industrial loads, harsh environments, or aging distribution often run semiannual surveys. Scanning should also be considered after a major electrical modification, after a significant load addition, and before a property acquisition.

Thermography identifies conditions; it does not correct them. The value is realized when findings feed directly into scheduled maintenance work — connections re-terminated to specification, damaged components replaced, and the affected points re-scanned afterward to confirm the fix.

Talk to Hargrove Electric

If your facility has never had a thermographic survey, the first one usually pays for itself in the findings it turns up. Hargrove Electric has served commercial and industrial clients across the Dallas–Fort Worth Metroplex for over 55 years, operating under Texas Electrical Contractor License #17522. Call 214-742-8665 or contact us online to schedule a walkthrough.