PV on a Solis inverter: PV negative ground fault (PV ISO-PRO02 = positive ground fault)
Short answer
On a Solis inverter, PV means: PV negative ground fault (PV ISO-PRO02 = positive ground fault). The inverter stops until the fault clears or is reset. The wording differs by model range — each is shown below.
Reviewed 24 September 2026 · 2 sources
What it means
On the S6-EH1P L-PLUS 48 V hybrids
The manual says: PV negative ground fault (PV ISO-PRO02 = positive ground fault).
Part involved: PV insulation.
Likely causes:
- PV string insulation problem; damaged PV cable; moisture/ageing modules.
On the S6-GR1P-S single-phase string inverter
The manual says: PV isolation protection.
Part involved: PV insulation.
Likely causes:
- String insulation fault; module ageing causing leakage in damp weather.
Is it safe?
On the S6-EH1P L-PLUS 48 V hybrids
Switch the inverter off at its isolator and call an engineer.
| Does the inverter stop? | Yes |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
The inverter stops until the fault clears or is reset.
Resetting itself: yes.
Manual reset: Often clears as weather dries.
On the S6-GR1P-S single-phase string inverter
Switch the inverter off at its isolator and call an engineer.
| Does the inverter stop? | Yes |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
The inverter stops until the fault clears or is reset.
Resetting itself: yes.
Manual reset: Clears automatically when weather dries; software update can help.
What you can check
On the S6-EH1P L-PLUS 48 V hybrids
- Read the full code and message on the inverter screen or in the SolisCloud app and note the date/time for your installer.
- Check the inverter's AC isolator next to the inverter and the solar/battery breaker in the consumer unit are ON (do not reset a breaker that trips again - call your installer).
- Note whether it only happens on wet/damp mornings.
On the S6-GR1P-S single-phase string inverter
- Read the full code and message on the inverter screen or in the SolisCloud app and note the date/time for your installer.
- Check the inverter's AC isolator next to the inverter and the solar/battery breaker in the consumer unit are ON (do not reset a breaker that trips again - call your installer).
- If it only appears on rainy days or early mornings and then clears, record the pattern for your installer.
What the engineer will check
On the S6-EH1P L-PLUS 48 V hybrids
- Insulation-test strings individually; inspect cables.
Who to ask for: MCS-certified solar PV installer (DC/string work) or the original installer.
Certification: Work on DC strings and inverter enclosures: competent PV installer (MCS-certified installer for warranty/SEG continuity); electrical work notifiable under Part P (England & Wales) or equivalent.
On the S6-GR1P-S single-phase string inverter
- Connect strings individually to locate fault; IR test; software update.
Who to ask for: MCS-certified solar PV installer (DC/string work) or the original installer.
Certification: Work on DC strings and inverter enclosures: competent PV installer (MCS-certified installer for warranty/SEG continuity); electrical work notifiable under Part P (England & Wales) or equivalent.
What you might notice
Sources
- User Manual for S6 Series Hybrid Inverter S6-EH1P(3-8)K-L-PLUS ↗ · Version 1.0 · page 54 · Reviewed 24 September 2026
- User Manual for S6 Series Grid Inverter S6-GR1P(2.5-6)K-S ↗ · Version 1.1 · page 43 · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026