Data Centres
Thermal imaging can identify abnormal breaker and protective-device behaviour within electrical systems serving data centres.
Discover MoreFailing Circuit Breakers Identified by Thermal Imaging
- ✔ PCN/ITC L2+
- ✔ ISO 18434-1
- ✔ Fully insured
- ✔ UK-wide
Understanding Failing Circuit Breakers and Protective Devices
Circuit breakers and related protective devices are designed to interrupt electrical supplies under defined fault or overload conditions. Thermal imaging can identify abnormal heating that may indicate deteriorating internal contacts, terminal resistance, ageing coils, mechanical wear or other developing conditions.
An elevated temperature does not automatically prove that a breaker will fail to operate. Heating can also be influenced by electrical load, adjacent equipment, enclosure ventilation and connection condition. Thermography is therefore used to identify abnormal behaviour that warrants informed investigation rather than to replace functional testing.
Our electrical thermal imaging surveys assess protective devices while electrical systems remain energised and operating under representative load. This page explains how failing breakers and related devices may present thermally, what the patterns may indicate and why specialist interpretation is essential.
The operational consequence depends on the device and circuit protected. A developing MCB or RCBO issue may affect a final circuit, while deterioration within an MCCB, shunt-trip assembly or motor protection device may compromise a larger distribution or production system.
Effective assessment considers the pattern and location of heat, circuit loading, similar devices, breaker construction, operating history and the consequences of loss of protection or unwanted disconnection. Safe isolation and appropriate electrical testing may then be required to establish the cause.
For a wider overview, visit our Common Electrical Faults Identified by Thermal Imaging guide.
Page Contents
- What Are Failing Circuit Breakers?
- Why Failing Circuit Breakers Generate Heat
- Thermal Imaging Examples
- Causes, Indicators, Equipment and Risks
- Where Breaker Defects Occur
- Corrective Action and Follow-Up
- Why Specialist Thermal Interpretation Matters
- Why Choose Red Current
- Industry Applications
- Frequently Asked Questions
What Are Failing Circuit Breakers?
Circuit breakers contain current-carrying contacts and mechanical operating components that must remain reliable throughout the device’s service life. Wear, repeated operation, fault-current exposure, contamination, ageing and connection deterioration can change electrical and thermal behaviour.
Thermal imaging may reveal heating across the breaker body, at terminals or around an internal component. The location and shape of the pattern help guide further investigation, but do not by themselves confirm the exact internal condition or protective performance.
Where a breaker or protective device is suspected of deterioration, the thermal finding should be considered alongside load, manufacturer information, inspection history and appropriate electrical or functional testing following safe isolation.
Why Failing Circuit Breakers Generate Heat
Internal Contact Resistance
Worn, contaminated or deteriorating contacts can increase electrical resistance and create heat within the breaker body while the device remains in service.
Connections and Internal Components
Heating may originate at cable terminals, internal contacts, coils or electronic components. Distinguishing the source is important because the appropriate investigation and response will differ.
Load and Enclosure Effects
A heavily loaded but serviceable device may run warmer than adjacent breakers. Enclosure ventilation and neighbouring equipment can also influence apparent temperature, making comparison and context essential.
Thermal Imaging Examples of Failing Circuit Breakers
Protective-device anomalies can occur within small final-circuit breakers, larger MCCBs and motor-protection equipment. The two examples below add an MCCB coil and motor overload unit to the MCB and RCBO examples shown above.
Important: Abnormal heating within a protective device does not in isolation confirm that the device will fail to trip, trip incorrectly or require replacement. Loading, component design, comparable devices, manufacturer guidance and appropriate electrical testing must also be considered.
Failing Circuit Breaker Characteristics
Common Causes
- Internal contact deterioration
- Mechanical wear and ageing
- Repeated switching operations
- Fault-current exposure
- Loose or high-resistance terminals
- Coil or accessory degradation
- Contamination or corrosion
Typical Thermal Indicators
- Breaker body hotter than comparable devices
- Localised terminal heating
- Internal hotspot away from terminals
- Uneven heating between poles
- Abnormal coil or accessory temperature
Affected Equipment
- MCBs and RCBOs
- RCCBs and protective devices
- MCCBs and ACBs
- Shunt-trip and undervoltage coils
- Motor protection breakers
- Motor overload units
- Distribution and control panels
Potential Risks
- Failure or delayed operation
- Nuisance tripping
- Loss of circuit protection
- Unplanned disconnection
- Equipment damage
- Process interruption
- Fire or arcing risk
Concerned About Abnormal Breaker Temperatures?
Red Current can assess protective devices under representative load, provide thermal and visual evidence, and deliver an independently reviewed report with prioritised recommendations. We also support electrical testing companies requiring specialist thermography.
Where Circuit Breaker Defects Commonly Occur
Thermal anomalies may be found within MCBs, RCBOs, RCCBs, MCCBs, ACBs, motor protection breakers, motor overload units and accessories such as shunt-trip or undervoltage coils. These devices occur throughout distribution boards, switchboards, MCCs and control panels.
A hotspot at a terminal may indicate a connection fault, while heating across the body or around an accessory may suggest internal component behaviour. The current path and device construction must be understood before the likely source is reported.
The four examples on this page span final-circuit protection, residual-current protection, a larger MCCB accessory and motor protection equipment. Together they demonstrate why protective-device anomalies should not be reduced to one generic breaker-failure pattern.
Corrective Action and Follow-Up
Thermal imaging identifies protective devices that warrant investigation; it does not replace safe isolation, inspection, manufacturer checks or appropriate electrical and functional testing. Corrective action may include checking terminations, testing operation, replacing degraded accessories or protective devices, addressing loading or improving enclosure conditions.
Where practicable, a follow-up thermal inspection under comparable operating load can help verify that the abnormal pattern has been resolved. Replacement or repair should be completed by an appropriately competent electrical contractor and in accordance with manufacturer requirements.
Need a Survey or Independent Verification?
Red Current can provide a specialist electrical thermal imaging survey or follow-up verification inspection under suitable operating load. Our electrically qualified, ITC/PCN certified thermographers provide clear thermal and visual evidence, independently reviewed reporting and prioritised recommendations, while your appointed electrical contractor remains responsible for isolation, testing and remedial work.
Why Specialist Thermal Interpretation Matters
Heat Does Not Confirm Protective Performance
Thermography can identify abnormal temperature but cannot by itself prove whether a breaker will operate correctly under fault conditions. Functional and electrical testing may also be required.
Terminal Heating and Internal Heating Differ
A localised terminal anomaly may arise from a connection fault, while heat within the device body may reflect contacts, coils, electronics or transferred heat. The distinction changes the investigation.
Comparative Context Matters
Device rating, circuit load, pole temperatures, adjacent breakers, enclosure conditions and manufacturer information all contribute to a reliable assessment.
Interpretation and Reporting Create the Value
The value of an electrical thermal imaging survey lies in converting thermal evidence and equipment 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 Testing Companies
Red Current can provide specialist thermographic inspection, interpretation and reporting while an electrical testing contractor retains the client relationship and responsibility for functional testing or 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
Protective devices range from compact MCBs and RCBOs to MCCBs, ACBs and motor-protection equipment. Red Current delivers electrical thermography across commercial, industrial and critical infrastructure environments, helping ensure each anomaly is assessed in the correct load and equipment 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 Failing Circuit Breakers
Failing or deteriorating protective devices can affect every electrical environment, particularly where continuity, production, safety or critical services depend on reliable circuit protection.
Manufacturing Facilities
Thermal imaging can identify abnormal breaker and protective-device behaviour within electrical systems serving manufacturing facilities.
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High Voltage Substations
Thermal imaging can identify abnormal breaker and protective-device behaviour within electrical systems serving high voltage substations.
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Hospitals & Healthcare Facilities
Thermal imaging can identify abnormal breaker and protective-device behaviour within electrical systems serving hospitals & healthcare facilities.
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Distribution Centres
Thermal imaging can identify abnormal breaker and protective-device behaviour within electrical systems serving distribution centres.
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Food Manufacturing Facilities
Thermal imaging can identify abnormal breaker and protective-device behaviour within electrical systems serving food manufacturing facilities.
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Commercial Offices
Thermal imaging can identify abnormal breaker and protective-device behaviour within electrical systems serving commercial offices.
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Schools, Colleges & Universities
Thermal imaging can identify abnormal breaker and protective-device behaviour within electrical systems serving schools, colleges & universities.
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Shopping Centres & Retail Parks
Thermal imaging can identify abnormal breaker and protective-device behaviour within electrical systems serving shopping centres & retail parks.
Discover MoreFrequently Asked Questions
Possible causes include internal contact deterioration, terminal resistance, ageing, repeated switching, fault-current exposure, coil or accessory degradation, contamination and excessive loading.
Thermal imaging can identify abnormal heating that warrants investigation, but it cannot alone prove that a breaker will fail to operate. Load information, inspection and appropriate electrical or functional testing may also be required.
No. The heat may originate from loading, a terminal connection, an internal component or transferred heat. The cause should be established before deciding whether adjustment, repair, further testing or replacement is appropriate.
A deteriorating breaker, coil or motor overload device may contribute to unreliable or nuisance operation, but other circuit and load conditions can produce similar symptoms.
No. Thermography assesses thermal behaviour under load. Protective-device operation must be evaluated using appropriate inspection and testing methods.
Terminal heating is concentrated around a cable or busbar connection. Internal heating may spread across the breaker body or be centred on contacts, coils or accessories. Equipment construction and the thermal pattern help guide further investigation.
Priority considers thermal behaviour, circuit load, device type, protected load, criticality, possible failure modes and the consequences of unwanted operation or failure to operate.
Specialist thermographers interpret protective-device patterns alongside loading, construction and operating context, then communicate findings through consistent reporting and actionable recommendations.
For broader survey questions, visit our Electrical Thermal Imaging Survey FAQs.
Abnormal Breaker Heating Requires Proper Investigation.
Thermal imaging can identify protective devices operating differently from comparable equipment, but temperature alone does not confirm protective performance or reveal the exact internal cause. Loading, equipment design, inspection and appropriate 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.
