Hidden Hazards of Open-Panel IR Thermography

Infrared thermography is one of the most effective tools in electrical predictive maintenance — but conventional open-panel IR inspection introduces operational hazards that are rarely quantified and frequently underestimated. This article examines the three most significant: productivity loss, ROI erosion, and arc flash exposure. We also cover the engineering solutions available to address them, including diagnostic monitoring software, ultrasound inspection, and IR inspection windows.

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Why IR Thermography Still Carries Real Risk

Infrared thermography is a proven, widely adopted condition monitoring technology. Its ability to detect thermal anomalies in energized electrical equipment — overloaded circuits, failing connections, imbalanced loads — before they cause unplanned downtime makes it a cornerstone of any serious predictive maintenance program. Used on motors, pumps, valve assemblies, switchgear, transformers, and distribution panels, IR inspection adds a diagnostic dimension that visual inspection alone cannot provide.

But no technology is without tradeoffs. Conventional IR thermography — the kind that requires opening energized panels — introduces three operational hazards that are rarely quantified and frequently underestimated: lost productivity, unrealized ROI, and unsafe working conditions. Understanding these hazards in detail is the first step toward designing an IR program that actually delivers on its promise. This article examines each hazard and concludes with the engineering solutions available to address them.

Hazard 1: Productivity Loss

Open-Panel Inspection Creates Compounding Downtime

Meaningful IR data requires inspecting equipment under load — ideally at or near 100% operating capacity — because thermal signatures are directly correlated with current draw. Inspecting during off-peak hours or night shifts reduces both the accuracy and the diagnostic value of the data. Hot spots that only manifest at higher loads go undetected entirely.

This creates a scheduling conflict with no clean resolution: inspect during peak operations and accept the productivity impact, or inspect during low-load periods and accept degraded data quality. Many facilities default to the latter, which means their IR program is systematically biased toward underdetecting the faults most likely to cause failures.

Timing consistency compounds the problem further. IR readings taken at different times of day — and therefore at different ambient and component temperatures — produce inconsistent baselines. Because radiant energy increases exponentially with temperature, even moderate variation in operating conditions can cause significant miscalculation of fault severity. A thermographer comparing readings across inspection cycles needs conditions to be as controlled as possible. Open-panel IR makes that difficult to achieve. Companies may even delay their inspection schedules entirely to avoid downtime, allowing costly and dangerous problems to grow undetected.

PPE Requirements Add Significant Man-Hours Per Panel

NFPA 70E and OSHA both mandate appropriate PPE for personnel working on or near energized electrical equipment. For open-panel IR inspections involving Category 3 or Category 4 arc flash hazard levels, this typically means full arc-rated suits, face shields, insulating gloves, and voltage-rated footwear.

The man-hour impact is substantial. Suiting up and dressing down with Category 3 or 4 PPE averages 30 minutes per person. For a three-person inspection team — two electricians and a thermographer — that adds 1.5 man-hours to every shift start and break. A time-motion analysis of a typical open-panel inspection reveals the following breakdown for a single energized cabinet:¹

• Two electricians require approximately 60 minutes to safely remove and replace a bolted panel cover
• The thermographer conducts the actual IR scan in roughly 6 minutes
• During the 60-minute panel removal and replacement process, the thermographer is idle for approximately 54 of those minutes
• The electricians are collectively idle for approximately 12 minutes while the thermographer completes the scan

The result: more than 3 man-hours of labor consumed per panel — the majority of it idle time, not productive inspection work. Across a facility with dozens of cabinets requiring inspection, the cumulative downtime is significant.

There is also a compliance risk embedded in this workload. PPE that is cumbersome, hot, and restrictive creates pressure — explicit or implicit — to shortcut. When bulky suits obstruct movement and visibility in tight switchgear enclosures, or when metal cladding limits access to bus joints and dead-front connections, the temptation to reduce PPE use is real. Incomplete PPE compliance during open-panel IR is not a hypothetical — it is a documented pattern.

Hazard 2: ROI Erosion

Labor Costs Per Panel Inspection Are Higher Than Most Facilities Track

The man-hour costs of open-panel IR inspection are frequently underaccounted because they are distributed across multiple cost centers — maintenance labor, contracted thermography services, and safety compliance — rather than appearing as a single line item. When aggregated, the cost to inspect a single energized panel using standard open-panel methods — at typical electrician and thermographer billing rates — runs approximately $435 per panel:¹

Multiplied across all inspectable assets in a facility, that figure scales quickly. Facilities with 50 to 100 panelboards, transformers, and switchgear assemblies requiring quarterly or semi-annual inspection are looking at substantial recurring costs — costs that do not reflect the value of the inspection itself, but rather the overhead of executing it under open-panel conditions.

Electrical Injuries Create Downstream Financial Exposure

Arc flash injuries incurred during open-panel inspection carry costs well beyond immediate medical treatment. Research on workers injured in electrical shock and arc flash incidents found that approximately two-thirds had not returned to work within two months of injury. Among those who did return, the average time away from work exceeded 108 days.² The financial implications — workers’ compensation, lost productivity, potential OSHA citations, and litigation exposure — can dwarf the cost of the original inspection program many times over.

Preventive maintenance economics generally favor early intervention over reactive repair. But that calculus only holds when the inspection method itself does not introduce new risk of the injury it is designed to prevent.

Hazard 3: Arc Flash and Electrical Shock Exposure

Electrocution Remains a Leading Cause of Workplace Fatalities

Electrocution is the fourth leading cause of workplace fatalities in the U.S. according to NFPA data. Electrical injuries occur with less frequency than many other EHS incident categories, but they carry disproportionately severe consequences. The National Safety Council estimates one fatality for every 30 electrical shocks.¹

Electric shock severity is determined by current magnitude, frequency, pathway through the body, and duration of exposure. The physiological effects across the current range relevant to workplace exposures are as follows:

Source: Controlling Electric Hazards, OSHA 3075, 2002 (revised)

The practical implication for IR inspection programs is direct: any activity that requires personnel to be present near exposed energized conductors — including panel removal — creates conditions in which shock and electrocution are credible risks, not theoretical ones.

Arc Flash Risk Is Highest During Panel Manipulation

Arc flash incidents are reported at a rate of approximately one every 18 minutes in the U.S.¹ Unlike most electrical hazards, arc flash does not require direct contact with an energized conductor. A phase-to-ground fault can initiate an arc that vaporizes copper conductors, produces a hyper-conductive plasma cloud, and releases energy in the form of a pressure wave, molten shrapnel, and thermal radiation exceeding the surface temperature of the sun — all within milliseconds.

The resulting pressure wave expands the vaporized copper conductor approximately 67,000 times its original volume. Arc-rated PPE provides meaningful protection against thermal burns, but offers limited protection against the blast overpressure and ballistic shrapnel produced by a high-energy arc flash event.

The triggers most commonly associated with arc flash initiation during electrical work include tool contact with energized parts, equipment state changes, and dropped tools or panels — each of which is a routine element of open-panel IR inspection.

The statistical comparison between arc flash and general workplace injury rates illustrates the disparity in severity: typical workplace tasks produce approximately 10 disabling injuries and one fatality per 10,000 near-miss incidents. Electrical arc flash incidents produce six disabling injuries and one fatality from just 85 near-misses — roughly two orders of magnitude more dangerous per incident.¹

NFPA 70E Hierarchy of Controls Defines Safer Alternatives

NFPA 70E’s Standard for Electrical Safety in the Workplace applies a hierarchy of controls framework to electrical hazards. At the apex of that hierarchy is elimination — removing the hazard entirely. Because IR thermography requires energized equipment, elimination is not available. Substitution and relocation are similarly unavailable.

Engineering controls represent the highest achievable level of protection for IR inspection of energized equipment. IR inspection windows — permanently installed optical ports that allow thermographic imaging through a closed, sealed panel — fit squarely within the engineering controls category. They are the most effective available alternative to relying on PPE alone, which sits at the bottom of the hierarchy.

Engineering Solutions That Reduce Exposure

Diagnostic and Monitoring Software

Real-time electrical monitoring systems use embedded sensors to track voltage, current, power factor, harmonic distortion, and other parameters continuously. When measurements deviate outside acceptable thresholds, alerts allow maintenance teams to intervene before a fault progresses to failure. These systems support condition-based maintenance scheduling — directing inspection resources toward assets showing early indicators of degradation rather than applying uniform inspection intervals across all equipment.

Supplementary circuit protection — arc-fault circuit interrupters (AFCIs), ground fault circuit interrupters (GFCIs), and current-limiting fuses — can further reduce incident energy exposure by deenergizing circuits rapidly when arcing signatures are detected.³

Ultrasound Inspection

Airborne and structure-borne ultrasound is an effective screening technology for energized electrical equipment, including transformers, motor control centers, switchgear, and relays. It detects corona, tracking, and arcing — all of which produce ultrasonic emissions detectable without opening panels.

Ultrasound functions as a pre-screening tool rather than a replacement for IR thermography. It allows inspectors to identify anomalies and prioritize panels for closer examination before committing to panel removal. Continuous online ultrasound monitoring — with permanently mounted transducers — provides 24/7 surveillance and immediate alerts for arc flash precursor conditions.

However, ultrasound cannot replace IR thermography for thermal fault diagnosis. When ultrasound identifies an anomaly, IR thermography is still required for definitive characterization — unless the inspection can be conducted through a closed panel.

IR Inspection Windows

IR inspection windows are permanently installed optical ports fitted with a lens material that transmits infrared radiation while maintaining the mechanical and electrical integrity of the panel enclosure. The thermographer positions the camera against the window and acquires thermal images of the enclosed components without opening the panel — no arc flash PPE requirement, no electrician support staff, no panel removal time.

The productivity impact is substantial. A documented case study from a U.S. paper mill illustrates the magnitude:¹

• Pre-installation: a two-person team required approximately 331 man-hours to complete IR inspection across 65 applications
• Post-installation of 197 IR windows: a single thermographer completed all 65 applications — plus 5 additional assets previously inaccessible due to incident energy levels — in 16 man-hours
• Total investment: $60,960 (equipment and installation)
• Payback period: two inspection cycles
• Cumulative productivity gain after five cycles: approximately $135,000

Because the panel remains closed, arc flash risk is reduced to less than 0.1%.¹ NFPA 70E classifies closed, guarded enclosures separately from open-panel work — IR windows eliminate the PPE requirement that drives much of the man-hour overhead in conventional IR programs. They are also NFPA 70E compliant as an engineering control.

Summary:

• Open-panel IR thermography introduces three compounding operational hazards beyond the inspection cost itself: productivity loss, ROI erosion, and arc flash and shock exposure.
• Scheduling and timing constraints make it difficult to conduct open-panel IR inspections under representative load conditions, reducing data quality and increasing the risk of missed or miscategorized faults.
• PPE requirements for Category 3–4 arc flash environments add more than 3 man-hours of labor per panel — the majority of which is idle time, not productive inspection work — at an estimated cost of $435 per panel.¹
• Electrical injuries sustained during open-panel inspection carry significant downstream financial exposure: two-thirds of injured workers do not return to work within two months of injury.²
• Arc flash initiates from routine inspection activities — panel manipulation, tool handling, equipment state changes — and is statistically far more likely to produce a disabling injury or fatality per near-miss incident than general workplace hazards.¹
• NFPA 70E’s hierarchy of controls identifies engineering controls as the highest achievable protection level for energized electrical inspection; IR inspection windows qualify as an engineering control and eliminate the conditions that drive arc flash risk.
• IR windows reduce inspection man-hours by approximately 90%, eliminate the arc flash PPE requirement, and typically pay for themselves within two inspection cycles.¹

References:

¹ 10 Things You Need to Know About Infrared Windows, IRISS, Inc.

² Occupational Injuries From Electrical Shock and Arc Flash Events, Fire Protection Research Foundation, March 2015

³ NEC 210.12, 2002 National Electrical Code Controlling Electric Hazards, OSHA 3075, 2002 (revised)