The short answer
When an SMA inverter detects a problem it records an event with a number and message, visible on the inverter’s user interface or in SMA monitoring products. SMA’s manuals give a cause and corrective measures for each event, and mark most of them for a qualified person. Your job as a homeowner is to read the event number, record it, check for outside causes like a grid outage, and pass it to your installer.
Safe checks you can do now
- Read the event number
Note the event number and message shown on the inverter or in your SMA monitoring. Photograph it with the date and time.
- Check for a grid outage or utility work
Several SMA events relate to the utility grid. SMA’s manual for event 401 says to make sure there is no power outage or work on the grid, and to contact the grid operator if necessary. Source: SMA manual: Event 401.
- Check whether data is just not updating
If the monitoring shows old data, the problem may be the network. SMA’s Sunny Home Manager manual lists router settings, devices being switched on and correct network connections as checks for data-update problems. Source: SMA manual (Sunny Home Manager 2.0): Problems with data update.
- Do not reset safety events yourself
Some events, such as an arc fault, stop the inverter on purpose. SMA’s manual says the reset is for a qualified person, after the inverter has been disconnected and the array checked for defects. Source: SMA manual (Sunny Boy, US): Resetting the operation inhibition after detection of an arc fault.
- Report it to your installer
Give your installer the event number, the time it started, and whether production stopped completely.
Only do the checks on this page that need no tools: read the app, look at the inverter or gateway lights, reset a tripped breaker that is labelled for the solar system or gateway, and look at the array from the ground. Never open an electrical panel, inverter, combiner or junction box, never touch wiring or connectors, and never climb onto the roof. Solar equipment can stay energized while the sun is up even when the grid is off. If a breaker trips again, you smell burning, or you see scorch marks, water in equipment or damaged wiring, stop and call your installer or a licensed electrician.
Common SMA event numbers, as SMA describes them
Meanings come from SMA’s own online manuals, linked per row. The manuals cover specific product families, so confirm the event text for your model. The homeowner column is our safe-action advice, not SMA’s.
| Event | What SMA’s manual says | What a homeowner can do |
|---|---|---|
301 | Grid incident: the ten-minute average grid voltage is outside the permissible range; grid voltage or impedance at the connection point is too high. (SMA manual (Sunny Boy Smart Energy, US): Event 301) | Note when it happens. Your installer checks the voltage; the utility may need to be involved. |
401 | The inverter disconnected from the grid because it detected a stand-alone grid or a very large change in grid frequency. (SMA manual: Event 401) | Check for an outage or utility work. Report it if it repeats. |
3501 | Insulation failure: a ground fault in the PV array; the inverter will not feed in while the fault exists. (SMA manual: Event 3501) | Stop. Call your installer or a licensed electrician. Do not touch the array or wiring. |
4301 | Electric arc detected; the inverter stopped feeding in. Reset is for a qualified person after checking the array. (SMA manual (Sunny Boy, US): Resetting the operation inhibition after detection of an arc fault) | Do not reset it. Call your installer: an arc fault is a safety event. |
Only events we could match to SMA’s own manuals are listed. For any other event, use the manual for your exact inverter model or contact your installer or SMA Service.
When to call your installer or an electrician
- Insulation failure (3501) or arc fault (4301) events.
- Grid events that repeat on sunny days with no outage.
- Any event that stops feed-in for more than a day.
- Any visible damage, burning smell or tripped breaker that trips again.
If you are not sure, treat it as a job for a professional. Our free remote review can help you decide what to ask for, but it does not replace a licensed electrician or your installer.
Get a free remote review of your system
Tell us which monitoring app your system uses (SMA). We send you the steps to add our team as a viewer or installer from inside the provider’s own app. You never share your password with us. Once access is granted, our team connects your system and runs a free remote review of your production and alerts, then tells you what we found and the next step.
- 01Tell us your monitoring brand
- 02Grant viewer or installer access in your app
- 03Our team reviews it and reports back
Remote data can show when and where production changed, but it cannot always find the physical cause. Some issues need an on-site visit or your installer. We never ask for your monitoring password.
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Questions homeowners ask
What does SMA event 301 mean?
SMA’s manual describes event 301 as a grid incident: the ten-minute average grid voltage is no longer within the permissible range, because grid voltage or impedance at the connection point is too high.
What does SMA event 3501 mean?
SMA’s manual describes it as an insulation failure, meaning the inverter detected a ground fault in the PV array and will not feed in while it exists. This needs a qualified person.
Can I reset an SMA arc fault (event 4301) myself?
SMA’s manual marks the reset for a qualified person, who must disconnect the inverter and make sure the PV modules, DC cables and terminals are not defective first.
Does Solar Survey AI review SMA systems?
Yes. Tell us you use SMA and we send the steps to grant our team access from your own monitoring account. We never ask for your password.
Related guides
Sources
- SMA manual (Sunny Boy Smart Energy, US): Event 301
- SMA manual: Event 401
- SMA manual: Event 3501
- SMA manual (Sunny Boy, US): Resetting the operation inhibition after detection of an arc fault
- SMA manual (Sunny Home Manager 2.0): Problems with data update
Brand-specific facts and error-code meanings come from the manufacturer’s own documentation, linked above, checked 2026-10-09. Manufacturers update their guidance; follow the current version for your equipment. Published by Solar Survey AI. Our safe-action advice is our own, not the manufacturer’s.