Solar panels are built and tested to survive hail, wind and heavy rain, but severe storms can still crack glass, damage cells or loosen fixings. Here is how the testing works, where the weak points are and what should happen after a storm. Solar panels are designed to live outdoors for decades, and certified panels are tested against hail impact, heavy wind pressure and moisture before they can be sold. Most storms pass without doing any harm. Severe hail, very strong gusts and flying debris can still crack glass, damage cells or loosen mounting hardware, and that damage is not always visible from the ground. Understanding how panels are tested, and where the real weak points lie, helps you judge the risk and respond safely after a big storm.
How panels are tested for hail
The front of a typical panel is a sheet of tempered, low-iron glass, commonly around 3.2 mm thick on glass-backsheet designs, with thinner glass on each face of many glass-glass designs. Tempering puts the glass surface into compression, which makes it far more resistant to impact than ordinary window glass. The full layer structure is covered in what solar panels are made of.
Under the international panel standard IEC 61215, certification includes a hail test: ice balls are fired at set points across the panel, with the baseline test using 25 mm ice balls travelling at about 23 metres per second. Afterwards the panel must show no major visual defects and must stay within tight limits for power loss and electrical insulation. Some manufacturers also test with larger hailstones, and this is often stated on the datasheet.
Two points keep those results in perspective:
- A pass means the panel survived the specified impacts in a laboratory. It does not make a panel hail-proof, and very large hailstones carry far more energy than the test ice balls.
- Real hail arrives at different sizes, speeds and angles, often driven by wind, so two panels on the same roof can fare differently in the same storm.
What wind does to a solar array
Wind is often the bigger engineering challenge. As air flows over a roof it creates suction, so the main force on a flush-mounted array is uplift, trying to pull panels and rails away from the roof. That pressure is uneven: it is highest near roof edges, ridges and corners, which is why designs keep panels out of edge zones or add extra fixings there.
In Australia, wind actions on structures are calculated under the loading standard AS/NZS 1170.2, which takes into account:
- Wind region: all of NSW sits in non-cyclonic regions, while cyclonic regions in northern Australia need much stronger designs.
- Terrain and shielding: an exposed hilltop or coastal headland sees higher wind speeds than a sheltered suburban street.
- Building height and roof shape: taller buildings and some roof forms increase local pressures.
- Tilt frames: panels tilted up on a flat roof catch wind underneath and need more robust fixing than flush-mounted panels.
Panels are load-tested as well. Certification includes a static mechanical load test on the front and back of the panel, and datasheets list the design loads the panel is rated for when clamped in the zones the manufacturer specifies. Clamping outside those zones can undermine the rating, so a correct installation follows the panel manual as closely as the racking engineer's tables.
The weakest link in wind is rarely the panel itself. It is more often the chain of connections: clamps to rails, rails to roof brackets, and brackets into rafters or purlins. If brackets are fixed only into battens or thin sheeting instead of the structure below, or if fixings corrode over time, a strong gust can find that gap.
Other ways storms cause damage
Hail and wind attract the attention, but storms bring several other risks:
| Storm effect | What can happen | How it is usually found |
|---|---|---|
| Flying debris and fallen branches | Shattered glass, bent frames, damaged cabling | Visual inspection, sudden drop in output |
| Impact without visible breakage | Microcracks in cells that can grow over months | Thermal imaging, IV curve testing, gradual underperformance |
| Lightning and grid surges | Inverter faults, failed monitoring devices | Inverter error codes, loss of monitoring data |
| Driving rain | Water entering damaged junction boxes, isolators or conduit | Insulation or earth fault alarms on the inverter |
| Roof damage | Lifted sheets or broken tiles around mounting brackets | Leaks, inspection of flashings and brackets |
Microcracks deserve a special mention. A cell can crack without the glass above it breaking. At first the effect on output may be tiny, but repeated heating and cooling can widen the cracks and isolate parts of the cell. That can show up as hot spots or as a slow decline that looks like faster-than-normal panel degradation.
Why a damaged array stays dangerous
The most important safety fact about solar panels is that they produce voltage whenever light falls on them. Turning off the inverter or the main switch stops power flowing into the house, but it does not make the panels or the DC cabling on the roof dead. A string of panels can carry several hundred volts of direct current in daylight.
That is why storm-damaged equipment should always be treated as live. Broken glass can expose conductive parts, wet cabling can create earth faults, and a partly detached panel can drag cables across sharp edges. Electrical work must be done by a licensed electrician, and solar repairs by an accredited installer.
What should happen after a severe storm
A sensible response keeps everyone off the roof and away from damaged equipment:
- Look from the ground. Check for shattered glass, displaced panels, fallen branches or hanging cables, using binoculars or a phone camera zoom.
- Check the monitoring app. Compare production with a similar sunny day before the storm. A sharp drop, a missing string or an error code is a strong clue.
- Read the inverter display without opening anything. Photograph any fault message.
- Keep clear of damage. If anything looks broken, burnt or wet, keep people and pets away and call a licensed professional. Only follow the posted shutdown procedure if the switches can be reached safely.
- Record everything for insurance. Take photos from the ground, note dates and output figures, and contact your insurer before arranging repairs.
- Arrange a professional inspection. An accredited installer can check the array, fixings and electrical safety, and test for hidden cell damage if output has changed.
Where a panel needs replacing, the new one must be electrically compatible with the rest of the string, matched on voltage and current characteristics rather than wattage alone. Warranties matter here too: manufacturer product warranties generally cover defects rather than storm damage, which is usually a matter for home insurance. The differences are set out in solar panel warranty types explained.
Next steps
If a storm has affected your system, or you want to know how your array is fixed and rated before the next storm season, professional checks are the safe route. Solar Fault Diagnosis ($249 for the call-out and first hour), an Electrical Safety Inspection ($299 for the solar system and switchboard) and Solar Panel Replacement (from $450 per panel, supplied and installed, minimum charge $650 per site attendance) are listed in the energy market. Prices are indicative and confirmed after a site assessment. For advice on a new, storm-ready system, request a free assessment from Blue Energy Solar.
Frequently asked questions
Does home insurance usually cover storm-damaged solar panels?
Many home policies treat rooftop solar as part of the building, so storm damage may be covered, but policies differ on excesses, limits and exclusions such as gradual wear. Check your product disclosure statement, tell your insurer promptly after a storm, and keep installation documents, serial numbers and monitoring data handy, because insurers often ask for a report from a qualified installer.
Should panels be removed before a forecast storm?
No. Removing and refitting panels is licensed, accredited work on a roof, and rushing it before a storm creates more risk than it removes. A correctly engineered array is designed to stay in place in the wind region where it is installed. What helps more is arranging for overhanging branches to be managed by qualified people and keeping monitoring online so any damage is spotted quickly.
Are glass-glass panels stronger in hail?
Glass-glass panels are stiffer and flex less, which helps protect cells from microcracks under wind loads, and they resist moisture well. However, each of their glass sheets is often thinner than the single front sheet on a glass-backsheet panel, so hail resistance depends on the specific model and its test results rather than the construction type alone. The datasheet and certification details are the best guide.
Please Login or Sign up to be able to comment