Thermal Imaging - A Solution In Locating Faults

Abnormal heat generation associated with resistance issues or excessive current flow is the primary cause of many problems in electrical distribution systems. Infrared thermography can see these invisible thermal signatures of impending faults or other damage before they occur.

The Unseen

Thermal imaging shows the technical professional what the naked eye can't. This technology works on the principle that faulty or weakening components often heat up before they fail, making them stand out like a in your disconnect or load center.

The Thermal Imager (Camera)

A thermal imager is an electronic tool that detects heat flow of infrared spectrum waves without having any direct physical contact with the observed component. Infrared radiation is directed by the imager lens onto a detector point, which is assessed by the camera circuitry in the thermal imager.

The output generated by the thermal imager is usually derived by a fluctuation in resistance or voltage, which is presented as an image (aka ... thermogram) on the imager display.

Thermal Imagers come in an array of types and resolutions, with some more sensitive then others (ie.. FPA - focal-plane array), based on the detector configurations and electronics.

History Of Thermal Imaging

Early imaging systems in the 1960-1970's were big and bulky matching the state of electronics at the time. The requirements of CRT (cathode ray tube) displays offered minimal portability.

Emissivity was also a concern with early equipment, since it is the measure of an object's ability to emit infrared radiation. That energy determines the temperature of the object being observed.

The late 1980's into the early 1990's brought surface mount electronics, smart integrated chips and LED, LCD displays, for higher sensitivity, software intelligence and portability, and as a result, lower initial cost of the equipment.

Explainer: How is the Emissivity value Rated? - Emissivity is rated on a scale of 0 (high quality mirror) to 1 (very black body). Different materials have values between these limits. Examples: Copper = 0.04, Glass = 0.95, Concrete = 0.91

The Faults that Lurk in the Shadows

What can thermal imaging do you for you?

From loose connections and overloads, to faulty breakers, and imbalances, thermal imaging can pinpoint issues long before they escalate into a full-blown high energy fault (arc flash), and/or fire.

Questionable Connections

Loose connections can lead to arcs, which is a spark that jumps between two conductive materials. This poses a fire hazard but also weakens the connection and builds resistance, leading to an overheat of the device.

Thermal imaging can spot these hotspots, alerting the electrical professional to potential concerns.

Overloaded Circuits

When circuits are pushed beyond their voltage or current handling capacity, they heat up, and thermal imaging can show that variant.

This is especially common in older facilities that weren't designed to accommodate our ever-increasing power demands, and may have been jury rigged by unknowing personnel.

Faulty Breakers

Faulty breakers can act up for various reasons, such as age, wear, or manufacturing defects.

Thermal imaging can identify overheating breakers, ensuring maintenance personnel can replace them before they fail dangerously.

Imbalanced Loads

Ideally, electrical loads are perfectly balanced, so they draw equal power from all electrical phases.

Imbalanced loads occur when the phases aren't pulling their weight evenly. This leads to inefficiency and can cause components to heat up.

Thermal imaging can pinpoint such issues, allowing the electrical professional to redistribute the load for a more balanced and safer scenario.

Causes Behind the Faults

Understanding a fault's root causes is crucial for for both the equipment, and professional, and end-user health and safety.

Age and Wear

Over the years, components can deteriorate, connections can weaken, and breakers can become unreliable.

Thermal imaging can help address these issues proactively.

Environmental Factors

Electrical enclosures are exposed to the elements, and their location can affect their reliability. Extreme temperatures, humidity, and corrosive conditions can speed up wear and tear.

Thermal imaging is a valuable addition for detecting the effects of these factors, providing the electrical professional with reaction time.

Manufacturing Defects

Sometimes, manufacturing defects in production defeat the best quality assurance systems. These defects can lead to unexpected failures.

Thermal imaging can potentially pickup defect anomalies in temperature allowing the faulty equipment to be replaced directly or under warranty.

Poor Maintenance

The lack of proper maintenance can lead to issues like loose connections, which thermal imaging can readily detect.

A scheduled maintenance program, along with either internal or external (thermography consultants) imaging inspections, is a way of making sure any downtime is not unscheduled.

Explainer: Does NFPA 70B Have An Electrical Maintenance Requirement? - NFPA 70B (The Standard for Electrical Equipment Maintenance) now requires the inspection of all electrical equipment at least every 12 months as of 2023. It also calls for thermal inspections based on the physical condition of the equipment. Consult NFPA 70B for full information. - NFPA 70B

Last Thoughts

Thermal imaging offers the ability to see beyond a physical observation of equipment. From loose connections to overloaded circuits and faulty breakers, thermal imaging can ensure a safer and more reliable electrical distribution system.

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