SMA is one of the longest-standing string inverter manufacturers in the solar industry, and its Sunny Boy and Sunny Tripower lines remain in service on thousands of older residential systems across Southern California. SMA inverters report faults as on-screen messages or numbered events, viewable on the unit’s built-in display or through Sunny Portal monitoring. Exact code numbers can vary by model and firmware version, so always note the exact message shown before calling for service.
Common SMA Fault Codes
| Display Message / Code | What It Means | Severity |
|---|---|---|
| Off: Waiting for Grid / Grid Fail | Grid voltage or frequency is outside acceptable range. Often a utility-side condition. | Low – usually self-clears |
| GFDI Fault (Ground Fault Detection Interrupter) | Loss of insulation resistance somewhere in the DC wiring, frequently from moisture intrusion or damaged cable. | Safety hazard |
| Arc Fault / AFCI Event | The inverter’s arc-fault circuit interrupter detected a DC arc condition. | Safety hazard |
| Isolation Fault | Reduced insulation resistance between DC conductors and ground, closely related to a ground fault. | Safety hazard |
| Fan Fault / Fan Warning | Internal cooling fan issue. Left unaddressed, leads to thermal throttling and eventual shutdown. | Moderate |
| Overtemperature / Temp Fault | Inverter is running hotter than its operating range, often tied to ventilation or mounting location. | Moderate |
| DC Overvoltage / String Voltage Fault | DC input voltage exceeds the inverter’s rated input, sometimes from string miswiring or extreme cold. | Moderate |
| Communication Fault (Sunny Portal / data logger) | Monitoring/reporting issue only – the inverter can still be producing normally. | Low |
| Persistent red LED, no display | Common on Sunny Boy units 10+ years old – often failed internal power components rather than a wiring issue. | Moderate-High |
This covers the fault categories homeowners encounter most often. SMA’s full manuals document additional codes specific to certain models and firmware versions – if your display shows a message not listed here, note it exactly and a technician can look it up for your specific unit.
Ground Fault and Arc Fault: Why These Codes Are Different
Most inverter fault codes affect performance – annoying, but not dangerous. Ground fault and arc fault codes are different. Both are safety detections built into the inverter specifically to catch conditions that can cause electric shock or start a fire, and both deserve a faster response than a typical production drop.
A ground fault (GFDI) means current is leaking outside its intended path, most often through damaged insulation, moisture intrusion, or a compromised connector. An arc fault means the inverter’s arc-fault circuit interrupter (AFCI) has detected electrical current jumping across a gap it shouldn’t – the exact mechanism behind many solar-related electrical fires, which is why AFCI protection on rooftop DC PV circuits has been required by the National Electrical Code (NFPA 70, Article 690.11) since 2011.
Resetting the inverter will often clear either code and let the system restart production. That reset does not fix anything – it only clears the fault flag. If the underlying wiring damage, moisture intrusion, or failed connector is still there, the condition can recur, sometimes without being safely detected and interrupted the next time. Repeatedly resetting a system that keeps throwing a ground fault or arc fault, instead of having it inspected, is how a manageable wiring issue turns into a safety event. If your system displays either of these codes, treat it as a signal to schedule a diagnostic inspection – not a nuisance to click through.
Repair or Replace?
SMA string inverters typically carry a 5-10 year standard warranty depending on model and year of purchase. Given how long SMA units have been in the field, many in service today are well past their original warranty window – which makes an accurate diagnosis (repair vs. full replacement) especially important before spending money on parts for an aging platform.
Important Safety and Liability Notice
This article is provided for general informational purposes only and does not replace a professional, on-site diagnosis. Solar inverters operate at high DC and AC voltages and involve real fire and shock hazards; do not open, probe, or attempt to repair internal inverter components yourself. ElectriCare, Inc. makes no warranty as to the completeness or current accuracy of manufacturer error codes referenced here, which vary by model, firmware version, and installation, and assumes no liability for property damage, injury, or system damage resulting from actions taken based on this content. If your system displays a ground fault, arc fault, or any code you’re unsure about, do not repeatedly reset the inverter to clear it – contact a licensed technician for evaluation.
Related Reading
- Inverter Errors and Failures: Complete Troubleshooting Guide
- Solar Arc Fault Errors: Causes, Risks and What to Do
- Your String Inverter Is Failing: Repair, Replace, or Upgrade?
Get Your SMA System Diagnosed
ElectriCare technicians diagnose and service SMA Sunny Boy and Sunny Tripower systems, including units well outside their original warranty window. Ground fault and arc fault calls are treated as priority service.
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Sources and Further Reading
- SMA Solar Technology – Official Product Support
- NFPA 70, Article 690 – Solar Photovoltaic Systems
- CALSSA – California Solar and Storage Association