It’s a Tuesday afternoon in an industrial park. On the roof of a high-value warehouse sits a 500-panel solar array that has reliably lowered energy bills for three years. Because it has performed so well, it’s rarely visited. But beneath panel 42, a family of rodents has found a warm, sheltered home. Over several months, they have gnawed through the UV-damaged insulation of a DC cable, eventually creating a high-energy electrical arc.
The resulting fire is small at first, but it quickly ignites the combustible elements of the roof structure. By the time the fire department arrives, they have no choice but to pour thousands of litres of water onto the array to suppress the blaze. The fire is extinguished, but the facility is now dealing with catastrophic water damage, ruined inventory, and a three-month business interruption—all originating from a defect that would have been caught during a simple visual inspection.
Preventable rooftop solar panel losses on the rise
While solar panels are a cornerstone of the green energy transition, they represent a shift in commercial property risk. At Aviva, we are seeing a growing loss trend where rooftop solar panels contribute to both property and liability exposures. Most stem from deterioration, poor housekeeping, missed inspections, and unmanaged defects over time rather than the technology itself.
While every design is different, a single commercial array can contain thousands of individual electrical connections. This includes the diodes housed within the panels—one-way valves that can fail and become hot enough to melt or liquify the plastic junction boxes on the back of the module. When these small failures occur out of sight on a rooftop, the “set it and forget it” mindset leaves these active electrical systems vulnerable to aging and neglect.
Here’s expert advice from our ARMS specialists to help you maintain your rooftop solar panels and know what to do in case of emergency.
Simple maintenance critical to preventing a claim
The most common misconception about commercial solar panels is that once they are commissioned, they require no further thought. In reality, these are live power plants sitting on one of the harshest environments possible: your roof. To protect your business continuity, a disciplined operation and maintenance (O&M) routine is essential.
The proactive inspection routine
Rooftop arrays are exposed to constant thermal cycling, UV radiation, and vibration. We recommend:
- Initial check: An early inspection should happen 3 to 6 months after handover to catch any early installation issues.
- Monthly visual checks: Facilities teams should walk the roof to look for signs of panel damage, loose securements, or water ponding.
- Annual thermographic (infrared) surveys: This is one of the most powerful tools in your kit. Infrared cameras can identify hot spots or failing diodes—one-way bypass valves that can melt or liquify plastic if they fail.
- Combustible construction rule: If a building uses mass timber, timber frames, or other combustible materials, the thermographic survey frequency should increase from annual to every 6 months.
- Qualified engineering reviews: At a minimum, a qualified engineer should perform a formal inspection annually to ensure the system still meets OEM standards.
- Modern tool deployment: Drone surveys or remote crawlers, which go under panels, are powerful tools for identifying DC corrosion or cable damage in hard-to-reach areas.
Specific care for inverters and isolators
Inverter failure is one of the most frequent causes of system performance loss. It’s important to do technical maintenance on the “brain” of the system. This should include re-torquing current-carrying conductor fasteners (screw lugs) to prevent loose connections.
And remind facilities teams to clean or swap inverter air filters after high winds or dusty conditions to prevent overheating.
Managing pests and the elements
Your roof is an attractive habitat for wildlife. Birds and rodents are drawn to the warmth beneath the panels.
- Pest control: If you see signs of nesting, implement pest control measures immediately to prevent wires from being chewed. Wiring should be housed in supported raceways and cable tracks to prevent pests from reaching them in the first place.
- Snow and ice management: On flat commercial roofs, snow can pile up directly on top of arrays, adding significant weight and potentially submerging components. Use soft tools like a snow rake to clear accumulation before it reaches 50% of the roof’s safe load limit.
- Cleaning without damage: Dust and algae can reduce production by up to 30%. Rinse but avoid using pressurized water jets, which can jeopardize the module junction boxes.
- Check arrays after storms: Do a visual check after high wind, storm, or hail events to ensure panels haven’t been loosened or struck by debris.
- Install electrical safeguards: Ensure all components have adequate surge protection and waterproofing for connections.
Have an emergency plan
If a fire does occur, your local fire department needs to know how to handle it safely. Solar panels remain live as long as they are exposed to daylight.
- Labeling and accessibility: Ensure that all ground-level disconnects are clearly labeled so that emergency responders can quickly isolate the building’s internal systems even if they can’t shut off the panels themselves.
- Note: Panels remain “live” as long as there is daylight. They can’t simply be turned off like a light switch.
- Staff training: Develop an emergency shutdown procedure and ensure your team knows exactly where the shut-off points are located.
- Documentation: Keep a clear log of all inspections, cleanings, and repairs. In the event of an insurance claim, these records are the best evidence of proactive risk ownership.
Get expert support from the ARMS team
Managing the risks of a rooftop solar installation doesn't have to be a solo effort. Our ARMS specialists are here to provide advice on everything from thermographic imaging to developing a robust O&M plan.
Reach out to us at arms.canada@aviva.com for more information.
