Solar systems are among the most reliable pieces of technology you can put on a building, but they are not entirely immune to faults, and because they sit quietly on the roof doing their job, problems can go unnoticed until you happen to spot a drop in generation. Knowing the common issues behind a solar panel repair helps you catch problems early, understand what an engineer is dealing with, and avoid both unnecessary worry and unnecessary expense. This guide runs through the faults we see most often and, just as importantly, what you can safely check yourself and what you cannot.
The inverter is the usual suspect
If a solar system stops generating or throws up an error, the inverter is the most common cause by a wide margin. It is the component that does the hard daily work of converting the direct current produced by the panels into the alternating current your home and the grid use, and that constant work means it is the part most likely to fail over the system’s life, often well before the panels themselves. Warning signs include error codes on the display, an unfamiliar pattern of lights, or generation simply stopping altogether. Inverter faults are firmly a job for a qualified engineer, not for any DIY intervention beyond the basic reset that the manual permits.
Drops in generation
If your output is lower than it should be for the time of year, the cause might be soiling or shading on the panels, a faulty panel or connection, or an inverter that is no longer running at full capacity. New shading is a surprisingly frequent culprit, whether from a tree that has grown, a new building or extension nearby, or even a television aerial installed after the panels. The quickest way to tell a genuine fault from normal seasonal variation is to compare your monitoring against the same period in previous years, since solar output naturally rises and falls through the seasons.
Physical and weather damage
Panels are built to withstand UK weather, including wind, rain and frost, but they are not indestructible. Storms, falling branches, hail and the occasional stray football can crack the glass or damage the frame, and loose or corroded mounting fixings are an issue that can develop slowly over years. Visible cracks, lifted panels, or anything that looks out of place after a storm should be inspected, both for performance and for safety, because a damaged panel can let water in, which creates an electrical hazard as well as a generation problem. A quick ground-level look after severe weather is a sensible habit.
Wiring, connections and isolators
Outdoor electrical connections degrade over time in the weather, and loose or corroded connectors, water ingress, or a failed isolator switch can all cause faults or intermittent generation. This is firmly electrical work and not an area for experimentation, because solar systems carry dangerous direct current voltages that are present whenever there is daylight, even when the grid supply is switched off. For that reason, connections must only be handled by a qualified electrician. It is one of the clearest cases where calling a professional is not just advisable but genuinely a matter of safety.
What can you safely check yourself?
Stick to the safe basics. Check your monitoring for an unexpected drop in generation. Look, from the ground, for any obvious new shading or visible damage. Check whether the inverter is displaying an error or has simply switched itself off. Make a note of any error codes shown, so you can pass them to an engineer, which often speeds up the diagnosis. Beyond these simple checks, anything involving the panels, the wiring, the isolators or the inside of the inverter should go to a professional. Guessing with live solar electrics is a genuine safety risk, not just a warranty concern.
Why ongoing maintenance prevents repairs
Many repairs are cheaper, or avoided entirely, when systems are checked regularly rather than only when something goes obviously wrong. A maintenance visit catches loose fixings, early inverter issues, soiling and connection problems before they turn into lost generation or a safety concern. It is the same logic as servicing a car: small, planned attention prevents large, unplanned bills. Our solar maintenance service is built to catch these things early, and it pairs naturally with our domestic solar installations so that systems we fit keep performing for the long term.
How long do solar systems last?
Solar panels are remarkably long-lived, typically generating for twenty-five years or more, with a slow, predictable decline in output rather than a sudden failure. The inverter is the shorter-lived component, often needing replacement at some point during the system’s life, simply because it works hard every day converting power. Knowing this in advance turns an eventual inverter replacement from an unwelcome surprise into a planned, budgeted part of owning solar. The rest of the system, properly installed and looked after, should quietly outlast many of the appliances it powers.
Choosing who repairs your system
If a fault does develop, who you call matters. Solar repairs involve dangerous direct current voltages and require both electrical qualifications and solar knowledge, so the right person holds both. A local, accredited installer who can work on the whole system is far better placed than someone who can diagnose one half and has to subcontract the other. It also helps if they can access your monitoring history, since that often points straight to the cause. Knowing who you would call before a fault occurs saves time and stress when one does.
Prevention beats repair
As with most things, prevention is cheaper than cure. A periodic maintenance check catches loose fixings, early inverter warning signs, soiling and connection issues while they are minor, long before they become lost generation or a safety concern. The cost of that occasional check is small set against an avoidable major repair or months of quietly reduced output. For a twenty-five year asset, a little planned attention is simply good housekeeping.
Frequently asked questions
What is the most common solar fault?
Inverter problems are by far the most common, because the inverter works hard every day converting power and is the part most likely to fail over the system’s life. Warning signs include error codes, an unfamiliar light pattern, or generation stopping. Inverter faults are a job for a qualified engineer rather than a DIY fix.
Why has my solar generation dropped?
The usual causes are soiling or new shading on the panels, a faulty panel or connection, or an inverter not running at full capacity. New shading from a grown tree or a nearby building is a frequent culprit. Comparing your output against the same season in previous years is the quickest way to tell a genuine fault from normal seasonal variation.
Can I fix solar faults myself?
Only the basics, such as checking your monitoring, looking from the ground for obvious shading or damage, and noting any inverter error codes to pass on. Anything involving the panels, wiring, isolators or the inside of the inverter must go to a qualified professional, because solar systems carry dangerous direct current voltages even when the grid is off. Guessing is a real safety risk.
In summary
Solar systems are highly reliable, but knowing the common faults helps you catch problems early and respond sensibly. The inverter is the usual suspect, drops in generation often trace back to shading or soiling, and physical or wiring faults need a qualified professional because of the dangerous voltages involved. Stick to the safe basic checks yourself, note any error codes, and leave the rest to an accredited engineer. Best of all, regular maintenance catches most issues before they become lost generation or a safety concern, which is why a little planned attention beats waiting for something to go obviously wrong. Treat your solar system like any long-lived asset: monitor it, maintain it, and call a professional for anything involving the panels, wiring or inverter, and it will keep earning its keep reliably for decades. The reassuring reality is that genuine faults are relatively rare on a well-installed system, and the ones that do occur are usually straightforward for a qualified engineer to put right. Knowing the warning signs, keeping an eye on your generation figures, and having a trusted local installer to call means a fault is a minor interruption rather than a lasting loss, and your system stays productive year after year.
How BJC Electrical can help
We diagnose and repair solar systems across Peterborough, Lincolnshire and Cambridgeshire, covering inverter faults, drops in generation, physical damage and wiring issues, as fully accredited electricians and MCS installers. Because we hold the electrical qualifications as well as the solar accreditation, we can safely work on every part of the system rather than diagnosing one half and subcontracting the other. If your system is not performing as it should, or is showing an error you do not understand, contact us for a proper diagnosis.
Catch faults early through monitoring and regular maintenance, leave the electrics to a qualified professional, and a solar system will keep earning its keep reliably for decades.
