GoodWe · PV inverters · GoodWe ET G2 6–15 kW (three-phase hybrid inverter)
F155Online Low Insulation Resistance
Name in the manufacturer's documentation (user manual): Online Low Insulation Resistance
[1]
In plain words (editorial)
The insulation between the PV side and protective ground is too low – the manual names a PV string short-circuited to ground or a long-term humid installation environment with poor line-to-ground insulation. This variant is detected while the inverter is running (online).
When to call a service technician: Have your installer check the PV strings and the inverter's protective ground wire. If the impedance is only too low in rainy weather, the manual allows the installer to reconfigure the insulation impedance protection point.
✎ editorial – written from the cited sources, not a manufacturer statement. Status: draft.
For technicians
Possible causes (source text)
Steps given by the manufacturer (source text)
- Check the impedance of the PV strings to Protection Ground. If a short circuit occurs, rectify the short-circuit point.[4]
- Check whether the inverter's Protection ground wire is correctly connected.[5]
- If it is confirmed that the impedance is indeed lower than the default value in rainy weather, please reconfigure the "Insulation Impedance Protection Point".[6]
⚠ Work on refrigerant circuits, mains electricity and PV DC wiring is for qualified technicians only.
The Polish page has more detail (plain-language explanation, safe checks, guides): Read in Polish →
Sources
Every statement has a footnote to the document and PDF page. “Quote verified” means the quote was found automatically in the text of that page.
- [1] GoodWe Residential Smart Inverter Solutions – ET G2 6-15K (+ LX F / LX D) – User Manual V2.2 (2026-09-30) (V2.2-2026-09-30) , p. 234 official manufacturer document quote verified
F155
- [2] GoodWe Residential Smart Inverter Solutions – ET G2 6-15K (+ LX F / LX D) – User Manual V2.2 (2026-09-30) (V2.2-2026-09-30) , p. 234 official manufacturer document quote verified
The PV string is short-circuited to Protection ground
- [3] GoodWe Residential Smart Inverter Solutions – ET G2 6-15K (+ LX F / LX D) – User Manual V2.2 (2026-09-30) (V2.2-2026-09-30) , p. 234 official manufacturer document quote verified
The PV string installation environment is humid for a long time, and the line-to- ground insulation is poor
- [4] GoodWe Residential Smart Inverter Solutions – ET G2 6-15K (+ LX F / LX D) – User Manual V2.2 (2026-09-30) (V2.2-2026-09-30) , p. 234 official manufacturer document quote verified
Check the impedance of the PV strings to Protection Ground. If a short circuit occurs, rectify the short- circuit point
- [5] GoodWe Residential Smart Inverter Solutions – ET G2 6-15K (+ LX F / LX D) – User Manual V2.2 (2026-09-30) (V2.2-2026-09-30) , p. 234 official manufacturer document quote verified
Check whether the inverter's Protection ground wire is correctly connected
- [6] GoodWe Residential Smart Inverter Solutions – ET G2 6-15K (+ LX F / LX D) – User Manual V2.2 (2026-09-30) (V2.2-2026-09-30) , p. 234 official manufacturer document quote verified
If it is confirmed that the impedance is indeed lower than the default value in rainy weather, please reconfigure the "Insulation Impedance Protection Point"