Fronius Inverter State 102 — AC Voltage Too High

What Does This Error Mean?

Fronius State 102 means the AC grid voltage at the inverter terminals is above the maximum permitted level. The inverter disconnects to comply with safety regulations. This usually clears automatically once the grid voltage drops back to a normal level.

Affected Models

Fronius Primo
Fronius Symo
Fronius Galvo
Fronius SnapINverter Series
Fronius GEN24 Plus

Common Causes

Grid voltage rise caused by many solar systems exporting power simultaneously in your street
Long or undersized cable run from the switchboard to the inverter causing voltage rise
Network voltage in your area consistently running high
Meter board wiring issue causing localised overvoltage

How to Fix It

Wait for the inverter to reconnect automatically.

Fronius inverters wait for the grid to stabilise and then automatically attempt to reconnect. Most State 102 events last only a few minutes and clear without any action. Check whether production resumed on the Fronius Solar.web monitoring portal.
Check Solar.web for how often State 102 occurs.

Log in to Solar.web (solarweb.com) and check the Events log for your inverter. If State 102 appears every afternoon between 11am and 2pm, neighbourhood voltage rise is almost certainly the cause.
Check whether neighbours with solar have the same issue.

Afternoon voltage rise is a systemic problem affecting entire streets or feeders. If your neighbours also have Fronius or other solar inverters tripping at the same time, this confirms a grid infrastructure issue.
Report to your electricity network operator.

In areas with high solar penetration, the electricity network is legally required to manage voltage. Contact your network operator (the company that owns the poles and wires, not your retailer) and report the voltage rise events.
Ask your installer about adjusting the voltage set point.

Fronius inverters allow the upper AC voltage trip point to be adjusted within limits permitted by local regulations. A licensed installer can increase the trip threshold slightly if the grid voltage is consistently near the limit.

When to Call a Professional

If State 102 occurs daily or prevents the system from producing for hours at a time, a licensed electrician or solar installer should measure the grid voltage and check wiring. The Fronius inverter's AC voltage set points may also need adjusting.

Frequently Asked Questions

Fronius State 102 happens every day at noon — is my inverter faulty?

No — the inverter is working exactly as designed. State 102 is triggered by the grid, not by a fault in the inverter. The voltage rise is caused by solar systems in your neighbourhood all exporting power at the same time. Report it to your network operator.

Will frequent State 102 events damage my Fronius inverter?

No — disconnecting on overvoltage is a protective feature. The inverter is not damaged by these trips. However, each disconnect represents lost production, so addressing the underlying voltage issue is worthwhile.