6602 on a SMA Solar Technology AG inverter: The effective value of the grid voltage is above the permitted voltage threshold values for a specified period of time (AF limit)
Short answer
On a SMA Solar Technology AG inverter, 6602 means: The effective value of the grid voltage is above the permitted voltage threshold values for a specified period of time (AF limit). The inverter stops until the fault clears or is reset. An engineer is needed to fix the cause.
Reviewed 24 September 2026 · 2 sources
What it means
The manual says: The effective value of the grid voltage is above the permitted voltage threshold values for a specified period of time (AF limit).
Part involved: grid voltage monitoring.
When it shows: The effective value of the grid voltage is above the permitted voltage threshold values for a specified period of time (AF limit).
Likely causes:
- SMA corrective measures: Check the grid voltage and connection on the inverter. If the grid voltage lies outside the permissible range due to local grid conditions, ask your grid operator if the voltage can be adjusted at the feed-in point or if it would be acceptable to change the monitored operating limits.
Is it safe?
| Does the inverter stop? | Yes |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The inverter stops until the fault clears or is reset.
Resetting itself: yes.
Manual reset: Automatic when condition clears.
What you can check
- Read the event number and message in the SMA Energy app / Sunny Portal (ennexOS) or the inverter's web interface and note the date/time for your installer. A red LED on the inverter means an event has occurred.
- If it happens once and the inverter resumes feeding in on its own, no action is needed; if the event keeps recurring, contact your installer.
- If neighbours with solar report the same, the local grid voltage may be high - your installer can raise it with the DNO.
What the engineer will check
- Measure grid voltage at the inverter connection point over time; check AC cable sizing/voltage rise; confirm country data set (G98/G99 UK setting); if grid voltage is persistently high contact the DNO - only change monitored limits with DNO agreement and SMA Service.
Who to ask for: PV installer / electrician; DNO liaison.
Certification: Installer liaison with the DNO; any change to grid-protection settings needs DNO agreement (G98/G99) and the manufacturer's installer/grid code.
What you might notice
Sources
- Operating manual SUNNY BOY SMART ENERGY 3.6/4.0/5.0/6.0/8.0/9.9 ↗ · SBSExx-50-BE-en-12 Version 1.2 · page 94 · Reviewed 24 September 2026
- Operating manual SUNNY TRIPOWER 3.0/4.0/5.0/6.0 ↗ · STP3-6-3AV-40-BE-en-20 Version 2.0 · page 94 · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026