SMA solar or battery system fault codes
SMA publish event messages rather than error codes, and they publish the most explicit safety wording of any manufacturer in this category. If you take one thing from these pages, take their sentence about not touching the substructure, the frame or the modules — not just the cables.
Where the code shows on a SMA
Modern SMA inverters have no screen. There is a light on the unit and the event number lives in the Results menu of the inverter’s own web interface, or in the system logbook in Sunny Portal. SMA link the two: if the red light is on and the Results menu shows 3501, 3601 or 3701, that points at a ground fault. SMA publish what the lights mean on their own. A red LED glowing is simply “event occurred”, and the event number is on the user interface. A green LED flashing two seconds on and two off is “waiting for feed-in conditions” — the conditions for feed-in operation are not yet met, and the inverter will start when they are. Green glowing or pulsing is feed-in operation, green off means it is not feeding in, and green and red flashing together means no country data set has been set. Blue is the network connection. The earlier Sunny Boy 3000TL to 5000TL-21 generation has a display, and shows the event number alongside a status such as “Check generator”. The numbers run in bands — 35xx for insulation, 36xx for leakage current, 37xx for residual current — which is an observation from their article set and manuals rather than a published rule.
How to reset a SMA
There is no owner reset for the insulation and residual current events, and SMA do not offer one. Their published corrective measure for both is to contact your installer for further investigation. For the leakage and residual current events SMA add that the inverter switches itself back on automatically once the values are back in the permissible range — so a system that came back on its own has not been fixed, it has been allowed to reconnect. What SMA do publish for an owner is a restart, in their article “How to Perform a Restart of an Inverter”, and it is deliberately an overnight one: switch off the inverter’s fuse or circuit breaker — which SMA note is in the AC sub-distribution, not in the inverter — overnight, and switch it back on the next morning. Their reason is that the inverter is then disconnected on the DC side too, because no PV is generated at night, and the waiting time to discharge the capacitors has been observed. Their second option, disconnecting the inverter from voltage sources in daylight, is “for this option please contact your installer”. On the ground fault events, their diagnostic procedure gives the reason better than any warning would: the insulation resistance can only be measured with a suitable device for safe disconnection and short-circuiting of the PV modules, and if no suitable device is available, the insulation measurement must not be carried out. That is SMA telling you not to attempt it without the right equipment.
Most common SMA faults
The SMA codes people look up most.
- 3501Stop — call an engineerInsulation resistance too low. SMA are unusually direct: the error is not caused by the inverter, it is in the DC installation — and it can come and go with the weather.
- Inverter not connecting to the gridGet it checkedSMA disable the grid connection deliberately when a pre-start check fails. The event number in the Results menu is what tells you which check.
- 3701Stop — call an engineerResidual current. Unlike the insulation event this one trips a running system, and SMA publish the threshold: a sudden jump of 30 milliamps or more.
Every SMA fault code
3 published codes. Filtering happens in the page — every one is in the HTML.
Showing 3 of 3 codes
| Code | What it means | Severity |
|---|---|---|
| 3501 | Insulation resistance too low. SMA are unusually direct: the error is not caused by the inverter, it is in the DC installation — and it can come and go with the weather. | Stop — call an engineer |
| Inverter not connecting to the grid | SMA disable the grid connection deliberately when a pre-start check fails. The event number in the Results menu is what tells you which check. | Get it checked |
| 3701 | Residual current. Unlike the insulation event this one trips a running system, and SMA publish the threshold: a sudden jump of 30 milliamps or more. | Stop — call an engineer |
SMA models
Codes can differ between generations. Check yours.
Guides that help with SMA faults
Looking for SMA’s own support? www.sma-uk.com. We are not affiliated with SMA.