Why Thermal Drone Surveys Are Becoming Essential for commercial Solar PV Systems

Solar PV has become an increasingly important part of the UK’s commercial and industrial buildings. Thousands of businesses are now using large roof-mounted solar arrays to reduce their electricity costs, improve energy efficiency and reduce their carbon footprint.

But once a Solar PV system has been installed, it is easy to forget that it is still an electrical installation operating on your roof every day.

Like any electrical system, Solar PV installations can develop faults over time. Loose connections, damaged cables, defective modules, failed bypass diodes and deteriorating connectors can all create abnormal heat.

In some cases, these problems may not be visible during a normal visual inspection.

This is where thermal imaging can provide an important additional layer of protection.

The recent Suffolk school fires highlight the importance of Solar PV inspections

Recent events here in Suffolk have brought the issue of Solar PV fire safety into sharp focus.

In June 2026, a fire occurred at Sidegate Primary School in Ipswich. Suffolk Fire and Rescue subsequently confirmed that a solar panel on the roof was the cause of the fire.

The incident followed fires at Brooklands Primary School in Brantham and East Bergholt Primary School, where solar panels were also identified as a potential factor.

Following the incidents, Suffolk County Council took precautionary action and temporarily switched off Solar PV systems at approximately 80 schools while further investigations were undertaken. The council stated that there was no conclusive evidence that all three fires were caused by the same problem, but considered the potential risk serious enough to warrant precautionary action.

These incidents demonstrate why Solar PV systems should not simply be installed and then left unchecked for years.

The UK Government’s Building Safety Regulator has also published research examining the fire safety implications of photovoltaic systems installed on buildings, including how PV systems can affect fire behaviour and firefighting operations.

What is a thermal drone survey?

A thermal drone survey uses a drone equipped with a specialist thermal imaging camera to survey the entire Solar PV array while it is operating.

The thermal camera detects differences in temperature across the panels.

A healthy Solar PV array should generally produce a relatively consistent thermal pattern. When a panel, cell, connector or other component develops a fault, it can produce a thermal anomaly or “hot spot”.

These abnormalities may be difficult or impossible to see with the naked eye.

A drone allows hundreds or even thousands of panels to be surveyed efficiently from above, without having to physically access every individual panel.

What can a thermal survey identify?

Depending on the nature and severity of the fault, thermal imaging can help identify:

·      Hot spots within individual solar panels

·      Defective or damaged PV cells

·      Problems with bypass diodes

·      Overheating junction boxes

·      Potentially defective electrical connections

·      Abnormalities associated with connectors

·      Panels or strings that may be underperforming

·      Developing faults that may otherwise remain unnoticed

·      Areas requiring further investigation or maintenance

The important point is that a thermal survey does not simply tell you whether a panel is hot.

It can identify thermal patterns that are different from the surrounding healthy panels, allowing potential problems to be investigated before they develop into a more serious failure.

Finding a problem before it becomes a fire

One of the biggest advantages of thermal imaging is that it can provide an early warning.

A developing electrical fault can generate heat before there is any obvious physical evidence of a problem.

For example, a poor electrical connection can create resistance. As current passes through the connection, heat is generated. If the problem continues, the connection can deteriorate further, potentially creating a much more serious fault.

Identifying an abnormal thermal signature gives the Solar PV engineer an opportunity to investigate the affected panel, connector or circuit.

The objective is simple:

Find the problem before it becomes an expensive repair – or potentially a fire.

Of course, a thermal anomaly does not automatically mean that a component is going to fail or cause a fire. Thermal imaging is a diagnostic tool, and any significant anomaly should be investigated by a suitably qualified Solar PV electrician.

Thermal surveys can also protect your investment

Fire prevention is only one reason to carry out thermal imaging.

A Solar PV system can suffer from faults that don’t present an immediate safety risk but nevertheless reduce its generation.

A single faulty panel may appear insignificant within an array containing hundreds of modules. However, multiple defective panels or a string-level problem can result in a significant loss of generation over time.

A thermal survey can therefore help identify both:

Safety issues – potential overheating and electrical faults requiring investigation.

Performance issues – defective panels, cells or components that may be reducing system output.

This makes thermal imaging a useful part of a proactive Solar PV maintenance programme.

Insurance requirements are changing

Commercial and industrial Solar PV owners should also check the requirements of their buildings and Solar PV insurance policies.

Insurance providers are increasingly taking a closer interest in the inspection and maintenance of Solar PV installations.

Zurich’s published guidance for photovoltaic systems recommends annual infrared testing and specifically states that large rooftop systems should consider the use of drones for aerial infrared imaging to identify PV module and equipment failures.

Allianz also provides Solar PV inspection services incorporating visual and thermal assessment and specifically identifies insurance compliance as one of the reasons for inspecting Solar PV systems.

For this reason, Solar PV owners should check their own insurance policy and speak to their broker or insurer to establish exactly what inspection, testing and reporting is required.

Do not assume that your existing electrical inspection is sufficient to satisfy your insurer.

A thermal drone survey should form part of a wider inspection

A drone survey should not be considered a replacement for a full Solar PV inspection.

The best approach is to combine:

1.      Visual inspection

2.      Electrical inspection and testing

3.      Thermal imaging of the PV array

4.      Inverter and system performance checks

5.      Investigation of any thermal anomalies identified

This provides a much more complete picture of the condition of the installation.

Where a thermal survey identifies a potential hot spot, the affected panel or electrical connection can then be physically inspected and tested.

Don’t wait until something goes wrong

Many commercial Solar PV systems installed during the early growth of the UK solar industry are now approaching or exceeding 10 years old.

Components such as connectors, cables, isolators and panels are exposed to the weather year after year, while the system continues to operate whenever sunlight is available.

Regular inspection provides an opportunity to identify developing problems rather than waiting for a failure.

The recent events in Suffolk demonstrate why this is becoming increasingly important.

A thermal drone survey is relatively quick, non-invasive and capable of inspecting an entire commercial Solar PV array while it is operating.

It could identify a problem that would otherwise remain hidden.

Does your commercial or industrial building have Solar PV?

At BME Electrical & Mechanical Services Ltd, we provide Solar PV inspection, testing and thermal drone survey services for commercial and industrial installations.

Our surveys can identify potential thermal anomalies and areas requiring further investigation, helping Solar PV owners:

·      Identify potential safety issues

·      Protect their Solar PV investment

·      Reduce the risk of unexpected failures

·      Identify potential generation losses

·      Maintain a record of the condition of their installation

·      Provide evidence of inspection where required by insurers

If you have a Solar PV system on your commercial or industrial premises, when was the last time the entire array was thermally surveyed?

If you are unsure, now may be a good time to arrange an inspection.

Contact BME Electrical & Mechanical Services Ltd to discuss your Solar PV inspection and thermal drone survey requirements.

BME Electrical & Mechanical Services Ltd – keeping commercial Solar PV systems safe, efficient and performing at their best.