Broken Glass on Solar Panels Can Cause Fires
Last updated at
During a recent SolarNet installation on a golf course home, broken panels needed to be replaced. The system was no longer operational, and the inverter was also to be replaced.
We found broken glass on solar panels. When the Sun Power modules were removed, we were very shocked to see burned areas directly under the areas of broken glass.
There is no reason to believe this is related to the brand of solar panels, but instead seems more likely to be related to the continued system operation of the system after multiple panels were damaged.
As we removed broken panels for replacement, we found two different generations of solar module models. It seems solar module damage has occurred before today’s incident. Installing Solar GolfNets at the first damage event could have prevented today’s eight panel failure.
What happens when a golf ball hits?
When a golfball hits, the impact pressure can break the topside glass, and can also shatter the internal solar cells. Electrical current flow at the fractures will cause an arc between fractured silicon pieces. The heat generated by the electric arc can easily melt the backside sheeting, exposing the underlying roofing material to high temperatures. This homeowner could have easily had a solar system fire.
Roof Material and Maintenance Matters
This particular home had concrete roof tiles, so the risk of fire spreading was probably minimal. If there had been an accumulation of debris such and leaves or pine needles, the outcome could have been tragic. Installing wire mesh around the perimeter can prevent debris from being trapped under solar modules.
Homes with a composition shingle roof will be at significantly higher risk than tile or metal roofing due to tar content of shingles.
Solar System Equipment
It is interesting to note that this system was approximately 10 yrs old. The inverter had failed, and was no longer functioning. It is likely the inverter failed due to the continual power surges caused by the arcing of multiple broken panels.
The inverter was manufactured before Arc Fault Circuit Interrupter (AFCI) detection circuits were mandatory for all inverters. A more modern inverter may have detected the arc, and shut down into an alarm state before heat damage became significant.
Continued Operation With Broken Solar Panels
Homeowners typically are content to continue using their solar system because "things seem to still be working". This leads to a false sense of security.
It is now clear that a broken solar panel creates a very real risk of fire damage. The fact that the solar system is still producing is not good news. It means electrical power is still flowing through the broken solar cells.
When solar panels are broken, systems should be immediately deactivated by switching off both the DC solar disconnect and the AC circuit breaker. This will interrupt the flow of current in the fractured area, preventing the internal electrical arc.
Continuing to operate solar system with broken solar panels can damage other solar equipment and create a rooftop fire hazard.