Reverse-DC on a Solis S6-GR1P-S single-phase string inverter: Reverse DC polarity
Short answer
On a Solis inverter, Reverse-DC means: Reverse DC polarity. The inverter stops until the fault clears or is reset. An engineer is needed to fix the cause.
Reviewed 24 September 2026 · 1 source
What it means
The manual says: Reverse DC polarity.
Part involved: PV polarity.
Likely causes:
- DC line reversed.
Is it safe?
Switch the inverter off at its isolator and call an engineer.
| Does the inverter stop? | Yes |
|---|---|
| Severity | Fault — needs a manual reset once the cause is fixed |
| Engineer needed? | Yes |
The inverter stops until the fault clears or is reset.
Resetting itself: no.
Manual reset: Installer corrects.
What you can check
- 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).
What the engineer will check
- Check DC polarity.
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 Grid Inverter S6-GR1P(2.5-6)K-S ↗ · Version 1.1 · page 42 · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026