- Solar and energy
- Solar inverter
103
Fronius inverter event 103
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
High
Quick answer
Fronius defines event 103 as: AC grid voltage is too low. The useful next discriminator is phase voltage, event time and connection-point condition. Preserve the event before any reset.
Safety first
Stop and check this first
- Do not change grid-code, voltage or frequency protection settings without installer and grid-operator authorization. Do not measure live boards yourself.
Safe checks you can perform
- Preserve the exact event context
- Collect one safe discriminator
- Respect the electrical stop point
Leave these tasks to a qualified professional
- Do not attempt this professional task: Measured handoff for Fronius 103
What a technician must be able to justify
A technician is coming
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Measured handoff for Fronius 103
What they doA qualified electrician should log phase voltages, frequency and connection-point impedance under the same export condition, then compare them with the active grid code and utility limits.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Checks and evidence, step by step
Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
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Preserve the exact event context
No special tools
Procedure
Save event 103, timestamp, inverter model/serial, firmware, red-LED state, affected phase/string, power and weather before clearing anything.
Do not change grid-code, voltage or frequency protection settings without installer and grid-operator authorization. Do not measure live boards yourself.
Evidence: Fronius Symo / Eco status diagnostics
- 2
Collect one safe discriminator
No special tools
Procedure
From the monitoring interface and a safe location, note whether other premises lost power and whether the event repeats at a particular export level or time. Record phase voltage, event time and connection-point condition; do not change multiple parameters or circuits at once.
Do not change grid-code, voltage or frequency protection settings without installer and grid-operator authorization. Do not measure live boards yourself.
Evidence: Fronius Symo / Eco status diagnostics
- 3
Respect the electrical stop point
No special tools
Procedure
If supply to the site is abnormal, involve the grid operator; if only the inverter repeats the event, a qualified electrician must measure at the connection point.
Do not change grid-code, voltage or frequency protection settings without installer and grid-operator authorization. Do not measure live boards yourself.
Evidence: Fronius Symo / Eco status diagnostics
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Solar and energy
- Brand
- Fronius
- Product type
- Solar inverter
Known code variants
- 103 Early Hints
- 103 Frühe Hinweise
- 103 Indications préliminaires
- 103 Indicios anticipados
- 103 Suggerimenti preliminari
- cargador Wallbox 103
- caricatore Wallbox 103
- chargeur Wallbox 103
- code Wallbox 103
- codice Wallbox 103
- código Wallbox 103
- erreur Wallbox 103
- error Wallbox 103
- errore Wallbox 103
- événement Fronius 103
- événement SMA 103
- evento Fronius 103
- evento SMA 103
- Fronius Ereignis 103
- Fronius event 103
- Fronius inverter 103
- Fronius Symo / Eco 103
- Fronius Wechselrichter 103
- HTTP 103
- HTTP status 103
- inversor Fronius 103
- inversor SMA 103
- inverter Fronius 103
- inverter SMA 103
- onduleur Fronius 103
- onduleur SMA 103
- SMA Ereignis 103
- SMA event 103
- SMA inverter 103
- SMA Wechselrichter 103
- Sunny Tripower X 103
- Wallbox app code 103
- Wallbox charger 103
- Wallbox error 103
- Wallbox Fehler 103
- Wallbox Fehlercode 103
- Wallbox Ladegerät 103
What it means
Official meaning: AC grid voltage is too low. Decision boundary: capture phase voltage, event time and connection-point condition. A qualified electrician should log phase voltages, frequency and connection-point impedance under the same export condition, then compare them with the active grid code and utility limits.
Warnings and stop conditions
- Mediumsource verified
Do not change grid-code, voltage or frequency protection settings without installer and grid-operator authorization. Do not measure live boards yourself.
Evidence: Fronius Symo / Eco status diagnostics
Symptoms and causes
Probable causes · in order
- What the Fronius event establishesConfirmed
The official Fronius Symo / Eco manual defines event 103: AC grid voltage is too low.
Evidence: Fronius Symo / Eco status diagnostics
- The observation that changes the next branchPossible
Capture phase voltage, event time and connection-point condition. If supply to the site is abnormal, involve the grid operator; if only the inverter repeats the event, a qualified electrician must measure at the connection point.
Evidence: Fronius Symo / Eco status diagnostics
Virtual technician
Does 103 still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
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Fronius Symo / Eco status diagnostics
Fronius International GmbH · 2025 · official_doc
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