Data Centres
Thermal imaging can identify developing UPS battery, capacitor and connection issues within critical-power systems serving data centres.
Discover MoreUPS System Defects Identified by Thermal Imaging
- ✔ PCN/ITC L2+
- ✔ ISO 18434-1
- ✔ Fully insured
- ✔ UK-wide
Understanding UPS System Defects
Uninterruptible Power Supply systems support critical electrical loads during disturbances, outages and transfer events. Thermal imaging can identify abnormal behaviour within batteries, capacitors, power connections, protective devices and UPS distribution equipment while systems remain operational.
UPS defects are not limited to batteries. Developing conditions may affect cable lugs, busbars, breakers, capacitors, rectifier and inverter assemblies, bypass circuits, cooling systems and associated panel boards. Some defects appear warmer than expected, while failed components may appear unusually cool.
Our electrical thermal imaging surveys assess accessible UPS assets under representative operating conditions. This page explains how UPS system anomalies may present thermally, why comparison between similar components matters and how findings can support proactive maintenance of critical power systems.
The operational impact depends on the affected component and the redundancy available. A deteriorating connection, battery or capacitor can reduce reliability, compromise runtime, contribute to unwanted transfers or increase the risk of a critical-power interruption.
Effective assessment considers UPS load, operating mode, redundancy, battery condition, cooling, phase currents, comparable components and the consequences of failure. The thermographer must distinguish a genuine defect from normal heat produced by power electronics and electrical load.
For a wider overview, visit our Common Electrical Faults Identified by Thermal Imaging guide. Related connection anomalies are covered in our High-Resistance Connections guide.
Page Contents
- What Are UPS System Defects?
- Why UPS Defects Create Thermal Anomalies
- Thermal Imaging Examples
- Causes, Indicators, Equipment and Risks
- Where UPS System Defects Occur
- Corrective Action and Follow-Up
- Why Specialist Thermal Interpretation Matters
- Why Choose Red Current
- Industry Applications
- Frequently Asked Questions
What Are UPS System Defects?
UPS systems combine energy storage, power conversion, switching, protection and distribution components. A defect in any of these areas can alter normal temperature patterns before a functional alarm or complete failure occurs.
Battery-bank anomalies may reflect cell deterioration, inter-cell connection resistance, terminal problems, charging behaviour or unequal thermal conditions. The thermal pattern should be considered alongside battery monitoring and electrical test information.
Thermography provides condition information without interrupting supply, but it does not replace battery impedance testing, UPS diagnostics, functional testing or manufacturer-recommended maintenance.
Why UPS Defects Create Thermal Anomalies
Electrical Losses and Component Ageing
Power electronics, connections and capacitors generate heat during normal operation. Deterioration can change resistance, losses and thermal behaviour.
Cooling and Operating Mode
UPS loading, rectifier or inverter operation, bypass status, ventilation and room temperature all affect the expected pattern. These conditions must be understood during inspection.
Hot and Cool Anomalies Matter
A deteriorating connection may appear hotter than comparable phases, while a failed capacitor may appear cooler because it is no longer functioning like the rest of the bank.
Thermal Imaging Examples of UPS System Defects
UPS defects can present as connection heating or as components operating unexpectedly cool. The two examples below add panel-board lug terminations and failed control-panel capacitors to the battery-bank and capacitor-heating examples shown above.
Important: UPS anomalies are not always hotspots. A component operating cooler than comparable units may indicate loss of normal electrical function. Assessment requires UPS load, operating mode, phase-current data, cooling conditions and comparison with equivalent components.
UPS System Defect Characteristics
Common Causes
- Battery or cell deterioration
- Loose or high-resistance connections
- Capacitor ageing or dielectric failure
- Power-electronic component degradation
- Cooling or ventilation deficiencies
- Electrical overloading or imbalance
- Age-related internal deterioration
Typical Thermal Indicators
- One battery or link differs from the bank
- Localised lug or terminal heating
- Capacitor hotter than comparable units
- Unexpectedly cool failed capacitor
- Uneven phase or busbar temperatures
- Abnormal UPS panel-board pattern
Affected Equipment
- UPS battery banks
- Rectifier and inverter sections
- Capacitor banks
- Input and output connections
- Static and maintenance bypass
- UPS panel boards and breakers
- PDUs and critical distribution
Potential Risks
- Reduced battery runtime
- Loss of redundancy
- Unwanted transfer or shutdown
- Component failure
- Loss of critical load
- Business interruption
- Fire or thermal runaway risk
Concerned About Abnormal UPS Temperatures?
Red Current can assess accessible UPS and critical-power equipment under representative operating conditions, provide clear thermal and visual evidence, and deliver an independently reviewed report with prioritised recommendations.
Where UPS System Defects Commonly Occur
UPS thermal anomalies may occur within battery banks, inter-cell links, terminals, rectifier and inverter sections, capacitor banks, static bypass assemblies, input and output connections, maintenance bypass equipment, panel boards and downstream PDUs.
A connection defect may produce localised heating despite balanced phase current, while a failed capacitor may appear cooler than comparable units. Understanding the current path and expected operation is essential when interpreting both patterns.
The four examples on this page span batteries, capacitors and distribution connections. Together they demonstrate that UPS thermography must assess both energy-storage components and the wider critical-power system.
Corrective Action and Follow-Up
Thermal imaging identifies UPS components that warrant investigation; it does not replace battery testing, UPS diagnostics, safe isolation, functional checks or manufacturer-led maintenance. Corrective action may include checking connections, replacing deteriorated cells or capacitors, investigating cooling, reviewing load or planning specialist service work.
Where practicable, a follow-up thermal inspection under comparable UPS load and operating mode can help verify improvement. Maintenance should preserve the required redundancy and follow the site’s critical-power procedures and manufacturer guidance.
Need a Survey or Independent Verification?
Red Current can provide a specialist electrical thermal imaging survey or follow-up verification inspection under representative operating conditions. Our electrically qualified, ITC/PCN certified thermographers provide clear thermal and visual evidence, independently reviewed reporting and prioritised recommendations, while your UPS service provider or electrical contractor remains responsible for testing and remedial work.
Why Specialist Thermal Interpretation Matters
Normal UPS Operation Produces Heat
Rectifiers, inverters, batteries and capacitors have expected operating temperatures. A warm component is not automatically defective without suitable comparison and operating context.
Cool Components Can Indicate Failure
A failed capacitor or inactive component may appear cooler than comparable units. Searching only for hotspots can therefore miss important UPS conditions.
Operating Mode and Redundancy Matter
UPS load, bypass status, charging condition, redundancy and cooling all affect thermal behaviour. These conditions must be understood before assigning significance.
Interpretation and Reporting Create the Value
The value of UPS thermography lies in converting thermal evidence and operating context into a defensible maintenance decision. Red Current’s assessments draw on electrical expertise, ITC/PCN certification, structured review and an in-house knowledge base developed from years of reporting data and millions of thermal images.
Specialist Support for Electrical and UPS Service Companies
Red Current can provide specialist thermal inspection, analysis and reporting while the UPS service provider or electrical contractor retains responsibility for diagnostics, testing and remedial work.
Why Choose Red Current for Electrical Thermography?
Realising the full value of an electrical thermal imaging survey depends on the competence of the thermographer, the quality of the inspection process and the clarity of the final report. Red Current combines electrical knowledge, certified thermography expertise and structured quality assurance to provide findings that can be understood, prioritised and acted upon.
Qualified Thermographers
Our electrical thermal imaging surveys are undertaken by electrically qualified, ITC/PCN certified thermographers. These recognised certification schemes provide structured training and assessment in infrared thermography, while our electrical qualifications and field experience support safe, technically informed inspection of live electrical systems. Thermographer competence matters because image capture, measurement, interpretation and reporting must be considered together.
Read more about why ITC/PCN thermography certification and surveyor competence matter.
ISO-Aligned Survey and Reporting
Our survey and reporting processes are aligned with ISO 18434-1, supporting a consistent approach to inspection, analysis and communication of findings. Reports are prepared to give maintenance teams clear evidence, appropriate context and practical priorities.
See our guidance on electrical thermal imaging standards, reporting and survey requirements.
Reviewed, Actionable Reporting
Thermal images alone do not provide a maintenance strategy. Our reporting process turns observations into documented findings with supporting thermal evidence, priority classifications and recommendations that can be used by facilities teams, insurers and electrical contractors.
Find out whether an electrical thermal imaging report can support insurance requirements.
Experience Across LV and HV Systems
UPS systems combine batteries, power electronics, capacitors, switching and critical distribution. Red Current delivers electrical thermography across data centres, healthcare, commercial and industrial environments, helping ensure each anomaly is assessed in the correct operating and redundancy context.
Explore our common electrical faults guide and high-voltage thermal imaging surveys.
Specialist support without competing for remedial work: Red Current can provide the thermographic survey, analysis and report while the client’s appointed electrical contractor or in-house electrical team completes any required investigation and remedial work.
Industries Affected by UPS System Defects
UPS system defects are particularly significant where critical loads rely on uninterrupted power, battery autonomy and resilient distribution.
Manufacturing Facilities
Thermal imaging can identify developing UPS battery, capacitor and connection issues within critical-power systems serving manufacturing facilities.
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High Voltage Substations
Thermal imaging can identify developing UPS battery, capacitor and connection issues within critical-power systems serving high voltage substations.
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Hospitals & Healthcare Facilities
Thermal imaging can identify developing UPS battery, capacitor and connection issues within critical-power systems serving hospitals & healthcare facilities.
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Distribution Centres
Thermal imaging can identify developing UPS battery, capacitor and connection issues within critical-power systems serving distribution centres.
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Food Manufacturing Facilities
Thermal imaging can identify developing UPS battery, capacitor and connection issues within critical-power systems serving food manufacturing facilities.
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Commercial Offices
Thermal imaging can identify developing UPS battery, capacitor and connection issues within critical-power systems serving commercial offices.
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Schools, Colleges & Universities
Thermal imaging can identify developing UPS battery, capacitor and connection issues within critical-power systems serving schools, colleges & universities.
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Shopping Centres & Retail Parks
Thermal imaging can identify developing UPS battery, capacitor and connection issues within critical-power systems serving shopping centres & retail parks.
Discover MoreFrequently Asked Questions
Thermography can identify abnormal battery or inter-cell connection temperatures, hot cable lugs, unequal phase connections, capacitor anomalies, cooling problems and unusual temperature patterns within UPS panels and distribution equipment.
An individual battery or connection behaving differently from comparable units may warrant investigation, but battery monitoring, impedance or conductance testing and manufacturer guidance are also required.
Yes. A capacitor that has lost normal electrical function may dissipate less heat and appear cooler than comparable operating capacitors in the same bank.
No. If phase currents are balanced but one or more lug terminations are hotter, connection resistance or another local issue may be more likely. Loading and comparison must still be verified.
No. Thermography complements battery testing, UPS diagnostics, functional testing and manufacturer-recommended servicing; it does not replace them.
Rectifier, inverter, bypass and charging conditions affect which components are active and how heat is distributed. The operating state is necessary context for interpretation.
Priority considers thermal behaviour, UPS load, redundancy, affected component, likely failure mode, battery autonomy, criticality and the consequences of transfer or loss of supply.
Specialist thermographers interpret both hot and cool anomalies alongside UPS operating mode, load, component function and critical-power context, then provide consistent reporting and actionable recommendations.
For broader survey questions, visit our Electrical Thermal Imaging Survey FAQs.
UPS Defects Can Appear Hot or Unexpectedly Cool.
UPS thermography is not limited to finding hotspots. Connection heating, battery differences and capacitors operating cooler than comparable units can all provide valuable evidence. UPS loading, operating mode, cooling, redundancy and appropriate follow-up testing are essential if findings are to support sound maintenance decisions.
Red Current provides specialist electrical thermography for end users, facilities teams, insurers and electrical testing companies throughout the UK. Contact us to request pricing, obtain a sample report or discuss a subcontract survey requirement.
