Info What does this mean?
A status message, not a fault. It usually clears on its own and needs no action from you.
Fronius Inverter STATE 103 Error: Meaning, Causes & Safe Fix
STATE 103 means the AC grid voltage is too low. The inverter has disconnected and will automatically resume once voltage returns to the permitted range.
What should I do first?
Two quick questions — we'll point you to the right starting point.
Is this code still showing on your inverter's display?
Is your system producing power right now?
What this code means
STATE 103 is a Class 1 grid status code: the inverter measured AC voltage below the permitted limit, so it disconnected from the grid as required by grid standards. It keeps testing conditions and resumes feeding power automatically once voltage is back in range for the observation period. This is typically temporary and caused by the grid — not a device fault.Common causes
- Temporary low voltage on the local grid (a brownout)
- High local demand straining the network
- Long cable runs causing voltage drop to your property
- A loose AC connection (less common)
Safe steps to try
Work top to bottom, ticking off each step as you complete it. 0 of 5 done.
Is your inverter still under warranty?
Before paying for a repair, check — your installer may fix this free.
Based on typical standard warranty terms — always confirm with your warranty card or installer paperwork, as terms vary by model, region, and purchase date.
When to call an electrician
Contact your system installer if STATE 103 keeps recurring — persistent undervoltage may need your network operator or an electrician to investigate your connection.
Frequently asked questions
Is STATE 103 dangerous?
No — it is the inverter doing its job, disconnecting when grid voltage is out of spec. It reconnects automatically.
Why does it happen at the same time every day?
Grid voltage dips during peak demand periods, such as early evening. If it is frequent enough to hurt your generation, your installer can advise.
103 vs 102 — what is the difference?
103 is AC voltage too low; 102 is AC voltage too high. Both are Class 1 grid statuses with the same automatic recovery.
Sources: meaning and troubleshooting verified against the manufacturer's documentation — Fronius Operating Instructions (Symo/Primo) — 'Status codes and remedy' / 'STATE CODES' tables (Fronius docs 42,0410,0192 & 42,0410,1909 series)