Thermographic Survey

Infrared Thermography and Load-Based Survey

Infrared thermography is a non-contact, non-destructive technique that measures the surface temperature of equipment and converts it into a visible map of heat flow. A hot spot is a symptom rather than a fault, so the value of the survey lies in measuring how far a reading departs from its reference, comparing it against its three-phase siblings and against its own history, and identifying the cause behind it.

Surveys are only reliable under load. An electrical panel at no load looks almost identical to a healthy one, and a motor that is cool at rest can still be badly unbalanced under duty. We therefore agree the operating condition in advance, load the equipment to a representative duty, allow thermal conditions to stabilise, and record the load against every measurement. That is what makes one survey comparable with the next, and what allows a rising trend to be caught before an alarm fires.

Thermographic survey detects:

• Loose connections, compression lugs and poorly torqued joints generating resistive heating
• Overloaded conductors, cables and switchgear rated below the load they are carrying
• Phase imbalance and single-phase loading on three-phase systems
• Induced heating from harmonics, stray flux or proximity to adjacent current-carrying conductors
• Blocked or fouled cooling paths, obstructed radiators and degraded fan performance
• Insulation and refractory deterioration, and localised loss of thermal protection
• Hot spots at terminations, joints and fuses inside switchboards and motor control centres

Thermographic Survey Applications

Thermographic survey is applied to:

• Switchboards, motor control centres, distribution boards and panel interiors
• Busbars, cable terminations, joints, lugs, compression connectors and fuses
• Power transformers, including bushings, radiators and tap changers
• Cables in trenches, on trays and at route joints
• Motors, generators, pumps and driven equipment
• Heat exchangers, cooling fin paths, radiators and lagging

Every survey records the thermal image, the measured temperature, the temperature difference against reference and the rise over ambient, alongside a severity rating based on the applicable standard and the equipment class. Findings are priority ranked so the most urgent action comes first, the likely cause is identified, and a re-survey after corrective action confirms the fault has been cleared.