Solar · Error codes · Fronius International GmbH
240-243Fronius International GmbH · Fronius SnapINverter (Primo, Symo, Eco, Symo Hybrid)
240-243 on a Fronius International GmbH Fronius SnapINverter: Arc detection
Short answer
On a Fronius International GmbH inverter, 240-243 means: Arc detection. 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: Arc detection.
Part involved: arc fault detection.
Likely causes:
- Fronius UK support: contact your installer to check the system.
Is it safe?
Switch the inverter off at its isolator and call an engineer.
| Does the inverter stop? | Yes |
|---|---|
| Severity | Safety lockout |
| Engineer needed? | Yes |
The inverter stops until the fault clears or is reset.
Resetting itself: no.
Manual reset: See engineer checks.
What you can check
- Read the state code on the inverter display or in Fronius Solar.web and note date/time for your installer.
- Do not touch the panels, DC cables or inverter; contact your installer. If you see smoke or smell burning, switch off the inverter's AC breaker if safe and call emergency services.
What the engineer will check
- Inspect DC strings, connectors and terminations for arcing damage; repair before re-enabling.
Who to ask for: Fronius-trained PV installer / Fronius Service Partner.
Certification: Qualified electrician (BS 7671; MCS-certified PV installer for work on the PV array/DC side).
What you might notice
Sources
- Help with Fronius SnapINverters - support for PV system owners (UK) ↗ · Fronius Primo 3.0-1 - 8.2-1 Operating Instructions (HTML 42,0410,2165, retrieved 2026-09-24) · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026