I just wanted to say thanks to the contributors to this thread as it has helped me with my system. I had a Sunny Boy 4000TL installed in early November and suffered about 2 outages per day due to "grid disturbance", with the inverter cutting out for about 11 minutes each time whilst it checked the grid voltage. By switching off and on again (on the AC) side I was able to get the start up message indicating German voltage settings ( I got ADJ rather than G83/1).
I also monitored the grid voltage which at that time was about 245-250 volts (it has since dropped to about 240-245 and I am close to my substation). As the G83/1 upper limit is 253 volts (230 + 10%), I was fairly sure that the inverter was set wrongly. After sum digging, I found that the inverter had been imported to the UK set to German voltages (which I guess must be about 250 max), but the importer assumed it was set to UK voltages as did the installer. SMA claim that the voltage setting should have been on a label on the box, but neither I nor the installer saw it. Unfortunately, after about 12 hours, the inverter protects itself from adjustment so that the country voltage settings cannot be reset using the mechanical dials (these should be 5 and 8 for the UK and were 0 and 0: the default). I have finally got the installers back who spent about 2 hours resetting it to G83/1 via security code (from SMA who were very helpful) and blue-tooth to the inverter. If only SMA had put a label on the inverter itself stating the factory setting, or the importer had done the same, or the installer had checked the setting and reset via the dials .... life would have been a lot simpler: but hey, I have learned a lot about the Sunny Boy, the European grid settings etc. The voltage limits are now 100-207 minimum and 264-280 maximum which should be fine.
I hope this helps others with the same issue.
Regards
Vaughan