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State 108

Fronius Solar Inverter

Severity: Moderate

Source: OnlyErrorCodes.com — Every error code. One place.

Fronius State 108 — Grid Voltage Too Low

What Does This Error Mean?

State 108 on a Fronius inverter means grid voltage is below the country's minimum (typically 195V on a 230V grid). The inverter disconnects per grid code. The cause is usually a brief brown-out or chronic low voltage in a long distribution line. Multiple events warrant a utility check.

Affected Models

  • Fronius Primo
  • Fronius Symo
  • Fronius Galvo
  • Fronius IG Plus
  • Fronius Tauro

Common Causes

  • Brief grid brown-out during heavy local load
  • Chronic low voltage on long distribution lines
  • Heavy industrial neighbour pulling voltage down
  • Failed AC connection at the inverter or panel
  • Transformer tap setting too low for the area

How to Fix It

  1. Check whether State 108 is recurring.

    Review Solar.web monitoring for the last 30 days. State 108 events at predictable times (e.g., evening peak) indicate chronic low voltage in the grid.

  2. Test household voltage during the event.

    If you can be home during a State 108 event, measure voltage at a nearby outlet. Sustained readings below 200V confirm grid-side issue.

  3. Inspect the AC connection at the inverter.

    Have your installer or a qualified electrician check the AC terminal connections. A loose connection causes voltage drop under load that triggers State 108 even when the grid is fine.

  4. Check home electrical panel.

    A loose breaker or bad neutral connection can cause apparent low voltage. An electrician inspection costs USD 80–150 and rules out home-side issues.

  5. Contact utility if voltage is consistently low.

    Document voltage readings over a week of State 108 events. The utility may adjust transformer tapping, replace conductors, or address upstream issues. The fix is typically free.

Frequently Asked Questions

Why does State 108 happen in the evening?

Evening is peak grid demand — everyone runs ACs, lights, and cooking. Marginal supply only fails the lower limit at peak. If State 108 only happens evenings, it confirms the issue is local grid loading rather than your installation.

What is the difference between Fronius State 105 and State 108?

State 105 is grid voltage too high (above 253V on 230V grid). State 108 is grid voltage too low (below 195V). Both are grid-protection events. State 105 is more common in PV-rich areas; State 108 is more common in long thin distribution lines.