background
Faulty photovoltaic systems have repeatedly caused major fires. This is not caused by technology, but usually by errors in the installation and maintenance process. But the danger can be minimized.
This is the evening of May 22nd. A barn is on fire near the Ostallgäu Untrasried. Rescuers were unable to save many cattle, and nearly 150 died. It is now clear that the fire was caused by a defect in the photovoltaic system inverter. A few weeks later, a warehouse in Inningen near Augsburg completely burned down for the same reason: a defective photovoltaic system.
Do solar power systems also increase fire risk? The number of photovoltaic systems will increase significantly in the coming years. If the federal government plans to, they should provide a total of 215 gigawatts of electricity in 2030. Currently about 67 GW.
Solar systems don’t burn very often
The experts initially came to a clear conclusion: Even if defective photovoltaic systems have caused devastating major fires, the technology does not increase the fire risk compared with other technical systems. This is the result of several studies, including from the Fraunhofer Institute and TÜV Rheinland. Statistically, solar systems burn as often or infrequently as other electrical systems in the home.
However, experts also agree that there are factors that can significantly reduce fire risk.
Missing fire protection measures and wrong materials
Markus Barnsteiner, district fire commissioner of the Ostallgäu fire brigade, said problems often started during rallies. By itself, it goes without saying that such a technical system can only be installed by specialists. If this doesn’t happen, there are often far-reaching consequences: “As a fire brigade, we often see photovoltaic systems installed on roofs, and then, especially on former agricultural properties, firewalls are often removed. They are built up.”
This is the worst possible scenario: Structural fire protection can do its job, but the superstructure of the PV system could allow the fire to climb over the walls and spread over a large area.
TÜV SÜD Electrical and Building Technical Inspector Stefan Veit emphasizes that the materials used in the installation must also meet special requirements. PV systems can often operate for years without any issues, but are exposed to the weather without protection, Veit said.
The fire brigade extinguished the burning photovoltaic system. Tensions represent a particular risk to emergency services.
Snow, wind and mink affect the system
Commercial cable ties, for example, can break due to intense UV radiation, and wind and snow loads can also stress the material over time. In addition, there are mink bites or stone chips, which increase the risk of fire due to loose plug connections, exposed cables or cracked modules.
“Furthermore, photovoltaic systems are often located in exposed locations, so there is an increased risk of lightning strikes,” Veit said. To minimize the risk of fire, effective lightning and surge protection must also be installed during installation.
But it’s not just damage that poses a problem: According to Veit, even heavy dirt can cause localized heating, increasing the risk of fire. That’s why it’s important to take care of your system, get it serviced regularly, and keep it in good working order, experts say.
Periodic inspections – by yourself and by experts
Surface damage can also be easily identified by a layman, according to the TÜV experts. He therefore recommends that every PV system operator regularly checks his system for damage. “But of course as long as you don’t put yourself in danger and you have adequate fall protection,” Witte said.
However, since a large number of possible defects lie below the surface, invisible to the naked eye, it is important to have regular maintenance and inspections by a qualified electrician; every four years is recommended. Using so-called thermal imaging images, experts can also identify deeper damage and replace worn parts early on, before they become dangerous.
Stefan Veit from TÜV SÜD recommends regular inspections of photovoltaic systems by experts and repeated inspections himself.
fireman switch and a plan to help in the event of a fire
In the event of a fire, taking precautionary measures can make it easier for the fire brigade to extinguish the fire, according to the Barnsteiner District Fire Commission. Photovoltaic systems generate a constant voltage, typically 600 to 1000 volts. In order not to put themselves in danger, emergency service personnel must keep a minimum distance from the system and avoid areas flooded with extinguishing water.
However, according to Barnsteiner, it is possible to install so-called “DC disconnects”. This feature, colloquially known as the “fireman’s switch,” shuts down the entire PV system with one action.
In addition, a detailed system plan is also important, explains the firefighter. Access to the interior of the building is important as the source of the fire is often hidden by photovoltaic modules on the roof and difficult to reach from the outside. With an accurate system plan, emergency services can easily see where the current-carrying lines will be laid in the house.
“Think about an emergency”
According to Barnsteiner, the general indication that there is a photovoltaic system on the roof is also important for the fire brigade: “For example, there are special stickers that say: ‘PV system on the roof’, which everyone can easily stick On top their power boxes can be connected.”
Because these measures are only effective if they can be quickly located by firefighters in an emergency, are easily accessible and are clearly marked, Barnsteiner said. He advises PV owners: “When installing, always consider emergencies – this helps us a lot.”