Do solar panels pose a fire risk?
Fires from solar panels are not impossible, but they are very rare. Solar panels are not even close to being on the top 10 list of causes of home fires. This list includes: cooking, heating equipment, smoking, electric appliances, candles, children playing with fire, faulty wiring, flammable liquids, Christmas trees, and barbeques.
As of 2015, changes to the California Building Code and California Residential Code require all PV systems be tested, listed and identified with a fire classification per UL 1703.
General expert opinion is that solar PV systems are at less risk of fire than any electrical equipment. Because they carry live wires, there will always be some risk, but this is negligible under normal circumstances. A very old, or very large, system will be most at risk, as will a damaged one.
There are several technical reasons for solar panels causing house fires, but most of them boil down to the same (avoidable) root: poor installation, although natural hazards such as lightning, overvoltage and power surges can also play a role. Wrongly-specified, wrongly-sized, or faulty equipment can also be to blame. Although very rare, once fire has taken hold in a solar system, it can be very difficult to resolve.
Like any other electrical installation, photovoltaic systems are subject to electrical faults such as arc faults, short circuits, ground faults and reverse currents. Faulty connections or cable insulation breakdowns can also cause problems. If these things occur, they can result in hot spots that can ignite flammable material nearby.
Another possible cause of fire is a DC arc. This is the most common cause of larger rooftop fires on commercial buildings, and can happen as a result of incorrect installation or problems in materials. A DC arc is a disconnection or fault in a current-carrying wire can cause an electric arc, which is a continuation of current flow through air, from one conductor to another, or to ground. Although arc flashes can occur with any electric installation, but solar PV systems are particularly sensitive to them because of the continuous DC current and the high currents and voltages involved. DC arcs do not self extinguish and they can reach temperatures as high as 3000°C. This is hot enough to melt metal, which can then fall and ignite nearby combustible materials.
Solar Panel Design and Firefighter Safety.
It’s extremely important for firefighters and their commanders to be able to identify homes with solar electric (photovoltaic or “PV”) systems and understand how these systems work. This article provides a consumer glance at some issues and current solutions.
Firefighter safety has been addressed by several organizations, resulting in guidelines to safely address a fire involving solar products. Additionally, our building codes now include provisions intended to address firefighter safety, such as minimum setback areas to provide space on the roof for walking around solar products, clear safety labeling, quick disconnects, and more. Product standards address safety in general, and specifically fire safety, and also include provisions to address the needs the firefighters.
One of the first things a firefighter does in a structure fire is cut the power for safety. But how do you do that when the power isn’t coming from the utility grid?
Currently, renewable energy systems (in California) are all required to have a solar electric quick-disconnect, or a “rapid shutdown mechanism.” This disconnect cuts the power from the solar energy system and serve to prevent harm or injury to first responders should there be a fire in or around your home.
The California Department of Forestry and Fire Protection – Office of the State Fire Marshal (CAL FIRE-OSFM), local Fire Departments (FD), and the solar photovoltaic industry have developed a guideline for installations to increase public safety for all structures equipped with solar photovoltaic systems.
Solarponics is proud to have had an active part in helping educate and train local area firefighters.
Solar panels and wildfire ash:
In wildfire areas that are experiencing ash fallout, the ash can settle on solar panels blocking sunlight, much like a heavy buildup of dust would do. The ash sediment can reduce power production by as much as 30% if not washed off.
A simple spray down with a garden hose will clean a solar array of loose ash, dust and other debris. It is best to scrub the panels clean with a soft sponge. If you have hard water and/or well water, you will need to squeegee the panels dry, or use an anti-spotting additive, such as what might be sued for washing your car.
- Rinse off panels.
- Sponge clean if they do not rise clean. Use a soft cloth mop, such as micro-fiber, and a non-metallic pole.
- If you have water spotting, mix an anti-water-spotting solution in a spray bottle. Spray rinse over entire panel surface.
Wash panels in the morning or early evening, when they are cool, and not in direct sunlight. It is advised to wait until air conditions clear, so that you won’t have to wash you panels again the next week. BE CAREFUL if climbing and walking on rooftops.
For those who really do not want to climb on their roof to clean their panels, we offer panel washing as part of your services. Call Deana, service department at (805) 466-5595.