Solar Inverter Error Codes Explained (Fronius, Sungrow, GoodWe & SolarEdge)

Solar inverter error codes are one of the most misunderstood parts of owning a solar system. A code appears on the inverter screen, generation stops, and homeowners are left guessing whether the issue is minor or serious.

This Solar Inverter Error Codes Explained guide is written to remove that confusion completely.

Instead of listing random numbers without context, this guide explains how inverter error codes actually work, why they appear, and how to interpret them correctly for the four most common inverter brands in Australia: Fronius, Sungrow, GoodWe, and SolarEdge.

This is a practical, real-world reference for Australian homes — not a generic manual copy.

Solar Inverter Error Codes Explained: How Error Codes Actually Work

Before looking at brand-specific codes, it’s important to understand one key fact:

Solar inverter error codes are safety mechanisms, not failures.

Every modern inverter constantly monitors:

Grid voltage and frequency
DC input from solar panels
Insulation resistance
Internal temperature
Communication with batteries, meters, or optimisers

When any value moves outside a safe operating range, the inverter triggers an error code and may temporarily shut down.

This logic applies across Fronius, Sungrow, GoodWe, and SolarEdge, which is why many error codes behave similarly even though the numbers differ.

Solar Inverter Error Codes Explained: What You Should Never Do

When an error code appears:

❌ Do not reset the inverter repeatedly
❌ Do not ignore recurring faults
❌ Do not open the inverter
❌ Do not assume the inverter is “faulty”
❌ Do not bypass safety shutdowns

Repeated resets can hide serious issues and void warranties.

One controlled restart is acceptable. Continuous resets are not.

Solar Inverter Error Codes Explained: Main Categories of Errors

Almost all solar inverter error codes fall into one of these categories:

Grid & network faults
DC voltage & insulation faults
Arc fault detection
Communication faults
Internal hardware protection
Temperature protection

Understanding which category the error belongs to matters more than the code number itself.

Solar Inverter Error Codes Explained: Grid & Network Faults (Most Common in NSW)

Grid-related errors are the most common solar inverter error codes in NSW, especially in suburbs with high solar penetration.

What Grid Error Codes Mean

Grid error codes indicate that:

Voltage is too high or too low
Frequency is unstable
The inverter cannot safely export power

These errors are normal protection behaviour, not inverter failure.

Common Grid Error Examples

Fronius: State 509, 516
Sungrow: Error 102, 103
GoodWe: Error 301
SolarEdge: Grid Fault 3x / 4x

Why They Happen

Too many solar systems exporting simultaneously
Weak local transformers
Long cable runs
Midday solar saturation

What To Do

✔ Wait — most clear automatically
✔ If frequent, installer may adjust grid settings
❌ No urgent action required unless persistent

Solar Inverter Error Codes Explained: DC Voltage, Insulation & Earth Faults

This category is critical and should never be ignored.

These solar inverter error codes indicate potential electrical safety risks.

What These Errors Detect

DC cable damage
Moisture ingress
Poor connectors
Insulation breakdown

Common Examples

Fronius: State 475 (Insulation Resistance Fault)
Sungrow: Error 202
GoodWe: Error 403
SolarEdge: Earth Fault errors

What To Do

❌ Do NOT keep resetting
✔ Shut down system
✔ Call installer immediately

These errors are designed to prevent fire and electric shock.

Solar Inverter Error Codes Explained: Arc Fault Detection (Serious)

Arc fault errors occur when the inverter detects abnormal electrical arcing in the DC circuit.

Common Causes

Loose MC4 connectors
Damaged panel cables
Poor installation workmanship

Brand Examples

Fronius: State 567
Sungrow: Arc Fault errors
SolarEdge: Arc Fault 8x

Action Required

❌ Do not restart repeatedly
✔ Immediate professional inspection

Arc fault errors are rare but serious.

Solar Inverter Error Codes Explained: Communication Faults

Communication errors are common in systems with:

Batteries
Smart meters
Monitoring platforms
Optimisers (SolarEdge)

What They Mean

The inverter cannot communicate with:

Battery modules
Smart meters
Optimisers
Internet gateway

Common Examples

GoodWe: Error 410
SolarEdge: Optimiser communication loss

What To Do

✔ Check internet connection
✔ Check visible cables
✔ Call installer if persistent

Many communication faults do not stop generation.

Solar Inverter Error Codes Explained: Internal Hardware & Relay Protection

Internal protection errors occur when the inverter detects abnormal behaviour inside its own electronics.

Examples

Relay protection triggered
EEPROM or firmware fault
Internal self-test failure

Brand Examples

Sungrow: Error 300 / 301
Fronius: Internal protection states

What To Do

✔ Restart once
❌ If error returns, warranty assessment required

These errors are rare but important.

Solar Inverter Error Codes Explained: Overtemperature Protection

Inverters shut down when internal temperature exceeds safe limits.

Common Causes

Poor ventilation
Direct sunlight
Enclosed installation location

Brand Example

GoodWe: Error 504

What To Do

✔ Improve airflow
✔ Shade inverter if exposed
✔ Installer relocation if recurring

Solar Inverter Error Codes Explained: Brand-Specific Behaviour

Fronius

Highly sensitive to grid quality. Most errors are grid-related, not inverter faults.

Sungrow

Very robust hardware. Errors usually relate to insulation or grid protection.

GoodWe

Installation quality matters greatly. Heat and cabling issues are common causes.

SolarEdge

Optimiser-level detection gives detailed fault visibility. Optimiser errors are informative, not always critical.

Solar Inverter Error Codes Explained: When to Call Your Installer Immediately

Call your installer if:

The same error appears daily
Any insulation or arc fault appears
System shuts down completely
Errors occur after rain
Battery disconnects repeatedly

Solar Inverter Error Codes Explained: NSW Grid Reality

NSW has one of the highest rooftop solar densities in Australia.

This means:

Grid voltage errors are common
Inverters are protecting themselves
Not all errors indicate system failure

A properly configured system will minimise unnecessary shutdowns.

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Conclusion

This Solar Inverter Error Codes Explained guide is designed to be a complete, long-term reference for Australian homeowners using Fronius, Sungrow, GoodWe, or SolarEdge inverters.

The key takeaway is simple: