The symptoms that mean repair, not cleaning
Soiling losses are gradual and even, every panel dims a little. Electrical faults are different: they show up as a sudden drop, a single panel or string flat-lining, or an error the inverter reports directly. If you see any of the following, a clean won't fix it.
- Production dropped and stayed down, even right after a rain or a clean, the kWh never recovered
- One panel or one string reads zero in your Enphase, SolarEdge, or SMA app while the rest produce normally
- An inverter or gateway error code, ground fault, arc fault, DC voltage fault, or a rapid-shutdown that won't clear
- The system is fully offline, no data reporting to the app at all
- Visible damage, a scorched connector, a chewed conduit, a cracked panel, or water in a junction box
- Intermittent dropouts that track with heat or time of day, the signature of a failing connection
What a repair visit covers
The C-46 specialist starts with your monitoring history, because the app usually points straight at the failed component before anyone climbs the roof. From there:
- Fault isolation, module-level data (per-panel for Enphase/SolarEdge) narrows the failure to a specific microinverter, optimizer, connector, or string
- Electrical testing, Voc/Isc string measurements, insulation-resistance checks, and thermal or clamp-meter readings to confirm the fault
- Component replacement, failed microinverter or optimizer swapped with a compatible unit; corroded MC4 connectors re-terminated; damaged conduit or wiring repaired
- Rapid-shutdown and safety, the code-required rapid-shutdown system is tested and restored so the array is safe for firefighters and future service
- Re-commissioning, the system is brought back online and verified reporting full production in your app before the specialist leaves
- Documentation, the fault, the fix, and the restored output are written up, which matters if a manufacturer warranty claim is involved
Cleaning first, when it's genuinely in doubt. If it's unclear whether you're looking at soiling or a fault, the honest first step is often a warranty-safe clean with before/after monitoring readings, it's cheaper and it settles the question. If production comes back, you needed a clean. If it doesn't, you have the data that proves the problem is electrical, and the repair specialist starts a step ahead. We won't sell you a $600 diagnostic for a $200 clean's job.
Why a licensed C-46 solar contractor, not a handyman
Rooftop solar is a live DC system that can carry 600 volts in full sun, with no off switch at the panel. California licenses solar-specific electrical work under the CSLB C-46 (Solar) classification for a reason. A general handyman or an unlicensed "solar guy" working on your array creates three real risks:
- Warranty loss, most manufacturer and installer warranties require licensed service. Unlicensed work voids them, turning a covered part into an out-of-pocket replacement.
- Fire and shock hazard, a mis-terminated MC4 connector or a defeated rapid-shutdown is a documented cause of rooftop solar fires
- Permit and inspection problems, improper repairs can surface later at a home sale or utility re-inspection
Every repair partner in the network holds a current C-46 (or C-10 electrical with solar scope), carries general liability with roof-work coverage, and discloses their license number before scheduling.
Warranty-safe by default
Panels, microinverters, and optimizers often carry their own 10-to-25-year manufacturer warranties, separate from the installer's workmanship warranty. A good repair protects those: the specialist confirms whether the failed part is still under warranty before replacing it, files or supports the claim where one exists, and installs compatible components so the rest of the array's coverage stays intact. Finding a failure inside the warranty window can mean a free part instead of a paid one, which is why documenting the fault properly is part of the job, not an upsell.
What it costs
- Diagnostic visit, a flat diagnostic fee, credited toward the repair if you proceed
- Single microinverter or optimizer replacement, commonly $300 to $650 including the part, when out of warranty
- Connector, wiring, or rapid-shutdown repair: $300 to $800 depending on access and extent
- String or multi-component fault: $800 to $1,500+ depending on how many units are involved
- In-warranty parts, often labor-only, once the manufacturer ships the replacement
Every repair is quoted in writing after the diagnostic, before any work starts.