One of the hazards that have always been prevalent among electronic equipment is the risk of spontaneously setting fire to anything nearby.
How much worse are the risks when installing a full-on solar system on your rooftop? Below we’ll be looking at just how safe solar panels have become in recent years, and whether there are any safety measures in place that minimize the risks.
Solar Panels as a fire Hazard
Although it can’t be helped that some high-profile cases have caused concern to grow among solar panel owners. For example, in 2018, when several rooftop solar panels caught on fire.
Check out our comprehensive solar panel installation guide to make sure you stay safe while working on your setup.
While the risk is low, it’s never zero; solar panels have live wires in them, meaning that there’s always some kind of fire risk involved. The specific metal used in solar panels is meant to counteract that kind of risk.
That is the case with any electrical device, however. In recent years technology has come a long way, involving several improvements being made to guarantee safety and minimize the risk of a spontaneous fire.
Risk of Fires Caused by Solar Panels
A solar power system that’s properly installed by the right people or company, certified and qualified, won’t bring any real risk to your home.
A photovoltaic (PV) solar system isn’t capable of starting a fire on its own. Some of the likely reasons that a fire does break out are because of an installation malfunction. This leads to some of the other components becoming flammable.
In the rare cases of solar panel fires, the main causes that most likely lead to them are either panels that are installed incorrectly or defective components like the sensors and junction box.
These issues usually cause arcs between conductors, to the ground, and even hot spots, leading to the ignition of any flammable materials nearby.
Installations Done Wrong
This is the most prominent reason why most solar panels catch fire in any case.
An incorrect installation usually means that the connectors aren’t connected properly, leading to electrical arcing and then combustion due to the sudden release of heat.
Installation should be left to the professionals, especially those who follow the instructions to a tee and also use the right tools for the job.
Common mistakes that happen during installation include several different things. This includes using the wrong crimping tools, poor wire management, using a different brand of connectors, and insufficient training experience.
When it’s done correctly, an installed solar panel system has little to no risk of a fire breaking out.
Out of all the components used in a solar panel, a defective junction box is usually the culprit behind it. This is because the junction box runs the risk of overheating.
The junction box sits on the back of the solar panel and is responsible for enabling electrical connections through a particular MC4 connector. Ironically, the electrical connection system is designed to prevent fires.
There were several fire incidents during 2012 that happened because of installations that were using defective polycrystalline modules and power junction boxes.
Those incidents became the textbook example for manufacturers to be more cautious and stricter with their components.
A similar incident has never happened again since, so it’s very likely that steps were taken to eliminate that issue entirely.
In the case of a house fire, a solar system can be a hazard, particularly when firefighters are not aware that a solar system is installed. Here are a few of those hazards:
- In some cases, a solar panel module can restrict the ventilation of a fire in prime spots of the roof.
- Solar Panels and batteries have toxic chemicals inside of them that could be released during a fire and are hazardous to inhale.
- Panels can become slippery, increasing the risk of a slip-and-fall accident for technicians, firefighters, and inspectors.
- The weight of a solar system could lead to roof collapse once structural integrity has been compromised by the fire.
- The conduit that leads from the solar panel to the inverter remains live with an electrical current even after the main panel has shut down. By unknowingly severing these lines, firefighters run the risk of suffering an electrical shock.
The best way to mitigate these risks is to make the responders aware of your solar system, where it is, and any other detail that could help them.
How Often Do Fires Happen?
There’s not enough factual data to make it clear how many instances of fires caused by rooftop solar panels happen in the U.S. but a solar panel system bursting into flames is exceptionally rare.
In a report discussing fire risks in Germany, out of 430 fires involving solar systems, only 210 were caused solely by the system itself.
From another perspective, that’s 210 out of 1.7 million installed solar systems. That’s equal to a 0.012% risk of fire occurring.
Minimizing the Risks
In the last decade, many improvements and advancements were made in both the technology used and international standards regarding solar systems.
These factors have gone to lengths to protect the equipment being used and the people interacting with it. Let’s take a look at what exactly has changed to ensure this level of safety for everyone involved.
The National Electric Code (NEC) has stated that the protection of both the consumer and first responders requires that the solar systems be shut down before any other issues can come from it.
Additionally, clear labeling should be used in the home or building to indicate power lines that are connected to the solar system, as well as where these components are. These measures are put in place so that firefighters can find them quickly enough and with relative ease.
On top of implementing safer and stricter code requirements, a lot of advances have been made in how solar panels are designed and the technology involved in making them.
This includes what is inside a solar panel, as the industry has gone as far as looking at the appropriate sizing of the electrical components and the right techniques used for installation. These are fundamental for minimizing any risks.
Solar system modules have to meet international standards for electrical performance and safety. This means that modern inverters now include overload protection, ground fault, arc fault, and over-temperature protection.
Design elements like these have made solar panels much safer than most electrical equipment in your home. On top of that, module-level power electronics (MLPEs) monitor the levels of the modules which allows for quicker problem identification.
Compared to the solar systems that were installed ten years ago, modern systems have significant differences and improvements because of the new safety standards that were put in place.
Advanced technology and higher standards are the two biggest factors that have led to safer solar systems. The Walmart solar panels were installed in 2012 before the states started to implement the improved 2014 or 2017 versions of the NEC.
The rapid shutdown rule, for example, was first introduced in the 2014 version of the National Electrical Code and is meant to simplify the way firefighters would have to de-energize a solar system.
This means that the system is able to turn off manually if there was an issue that prevented the AC current from reaching the inverters.
Later, in the 2017 NEC, the rapid shutdown rules were updated to include module-level shutdown. The issue was that even though the inverter is switched off, the DC (direct current) wiring remained energized while the sun was shining.
To meet the new standards, MLPEs are required to reduce string voltage and give a manual activation of rapid shutdown features.
The only thing left is the AC breaker, which is the only switch that would need to be flipped. This protects the system and guarantees personnel safety.
Inspecting for Design Elements
Inspectors working with InterNACHI (International Association of Certified Home Inspectors) are required to look at a few design elements in the solar module to make sure fire risks are kept to a minimum.
A few of those elements include:
- Installing a solar system needs to be done by and then regularly inspected by a qualified professional.
- A shut-off valve has to be present on the rooftop. It’s a switch that can be utilized to turn off the DC that’s running from the solar panels into the conduit.
- Checking for damage made by rodents or other pests that could compromise the insulation or wiring.
- There should be enough pathways and space around the solar system for inspectors and firefighters to move around safely.
- A section of the roof needs to be left open, in case firefighters need to use that space to create ventilation during a fire, should it be necessary.
To sum it up, solar panels are probably safer than most electrical equipment you use in your kitchen. Not to mention that a lot of effort and focus on regulations and solar panel designs are heavily focused on their safety.
Companies and organizations do what they can to protect you, the consumer, as well as the installers and firefighters that need to interact with the solar systems.
Now, whether solar panels can cause cancer or not, is an entirely different story that is more related to the kind of radiation they give off.
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