The rise and risks of solar panels
Along with many other countries worldwide, the UK is increasing the proportion of energy that is obtained from renewable sources. One of the most popular, is the production of electricity from solar energy using photovoltaic panels, or solar panels as they are better known. Zurich are seeing an increasing number of incidents of fire claims involving solar panels, and we are currently working with other experts to better understand this trend.
What is a Photovoltaic (PV) system?
In simple terms PV panels convert the energy from the sun into electricity. PV cells within each panel turns solar radiation into direct current (DC) electricity. A PV system also has an invertor which converts the DC power to alternating current (AC), which ultimately flows to our power sockets. Each panel is connected to each other by a simple male to female connector as shown below. These connectors are situated on the underside of each panel.
(1) image taken from https://www.solar-electric.com/learning-center/how-to-use-mc4-connectors-cables.html/
(2) image owned by Multi-Contact AG - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=23953040
Most commonly the panels are fixed to the roof of a property in order to have uninterrupted access to the sun’s rays. We will commonly see them fitted to domestic buildings flat on an angled roof, or at an angle to flat roof commercial properties.
Are roof mounted PV panels a fire hazard?
When any electrical equipment fails, in your home or workplace, it can turn into a source of fire. It makes sense then, that by introducing an additional electrical source, such as PV panels, the risk of fire increases. The Building Research Establishment, have identified the potential for fire incidents involving solar panels, and as a result have attempted to identify the common causes. The main origin has emerged as electrical arcing between conductors within defective or incorrectly installed components. A close second are ground faults, often a pre-cursor to arc faults. Research has identified other electrical components on PV systems that are associated with an increased fire risk. Those that emerge as the most common candidates are DC connectors, DC isolators and to a lesser extent Invertors.
If we conclude that electrical “faults” are the predominant cause of fire, then common sense tells us that to mitigate the risk, we should consider how we can minimise their occurrence. But if the majority of electrical connections are situated underneath the solar panels, which in turn are securely fixed to the roof as we saw above, how do we inspect and maintain the connections? In many instances scaffold would be necessary to access the panels, plus significant time and expertise to remove (and replace) each panel to permit inspection of all electrical connections. It should be pointed out here, that PV systems are generally marketed and sold as being maintenance free.
Further challenges arise from the varying quality of installation. Whilst solar PV products must meet the UK’s quality assurance standards, there are currently no regulations in respect to installation. Whilst accredited installers are available and recommended, the consumer is not protected by law.
What happens in the event of a fire?
In the event of fire ignition, is fire extinguishment affected? There are a number of elements to consider:-
Fire detection – usually and for good reason, focusses on the detection of fire inside a building. Therefore, when a fire that starts externally, traditional detection methods will only operate once the fire has tracked into the building. Early discovery relies on manual alerts such as a passing motorist or pedestrian.
Additional combustible materials – PV systems have combustible and non-combustible materials. Zurich loss experience indicates that where PV systems have been involved in fires, combustible components have contributed as a fuel. More importantly however, the PV panels in the early stages of a fire, will continue to generate electrical current. Not only does this act as fuel, an uninterruptible power source creates a hazardous environment for fire-fighting.
Fire spread – as PV panels are fixed to the roof surface, they shield large areas of the roof from the direct application of extinguishment water. Additionally, when mounted at an angle they create concealed spaces between the panels and roof, and in the presence of wind, these “tunnels” aid the spread of fire.
A recent claim displayed the potential for significant structural damage following a fire that began at an array of solar panels. What began as a relatively confined fire spread swiftly, fuelled in part by additional combustible sources, and caused significant damage.
What next?
Claims are working together with Zurich Risk Managers and Underwriters, and with our external partners, to gather further information to inform our risk management strategy. It may be that tighter controls are required to ensure appropriate installation and minimum maintenance requirements. We have in the past successfully lobbied Parliament to ensure necessary steps are taken where we have identified unacceptable risks.
