Troubleshooting · 5 min · Updated 11 October 2026

Huawei inverter alarm codes explained

Short answer: Huawei SUN2000 alarms fall into four groups: the grid (for example 2032 Grid Failure), the solar panels (for example 2062 Low Insulation Resistance), the battery (2068 Battery Abnormal) and internal faults (2064 Device Fault). Grid alarms that happen occasionally clear by themselves when the grid is normal. Alarms that persist or keep returning need a professional.

The tables below are based on the alarm table (Table 8-2) in Huawei's user manual for the SUN2000-(2KTL-6KTL)-L1 residential inverters, issue 06. Other SUN2000 models use many of the same IDs and names, but details can differ. Always check the manual for your exact model if you can. You see alarms in FusionSolar under the plant's alarm list.

First: safety

Never open the inverter or the battery.
Do not touch DC cables from the panels. They can be live whenever the sun shines.
Only use the switches your installer has shown you.
Note the alarm ID and time before doing anything.

How Huawei rates alarms

Severity	What it means, according to Huawei
Major	The inverter shuts down or functions abnormally
Minor	Some components are faulty, but it can still connect to the grid and generate power
Warning	The inverter works, but output is reduced by external factors

Grid alarms

These alarms mean the inverter has detected grid conditions outside the allowed range. Disconnecting is a safety function.

ID	Alarm	Cause, according to Huawei	What you do
2032	Grid Failure	Grid outage, or the AC circuit is disconnected or the AC breaker is off	Check for a power cut and whether the inverter's AC breaker is on
2033	Grid Undervoltage	Grid voltage below the lower threshold	Occasional: it recovers by itself. Frequent: see below.
2034	Grid Overvoltage	Grid voltage above the higher threshold	Occasional: it recovers by itself. Frequent: see below.
2036 / 2037	Grid Overfrequency / Underfrequency	Grid frequency outside the local standard	Occasional: it recovers by itself
2038	Unstable Grid Frequency	Frequency changes faster than the local standard allows	Occasional: it recovers by itself
2039	Output Overcurrent	Grid voltage dropped sharply or the grid was short-circuited	Recovers when the fault is gone. Frequent: contact installer.

For voltage and frequency alarms that happen frequently, Huawei says to check whether the grid is within the allowed range and contact the local power operator if not. Protection thresholds may only be changed with the grid operator's consent. That is a job for your installer, not for you.

Solar panel (PV) alarms

ID	Alarm	Cause, according to Huawei	What you do
2001	High String Input Voltage	Too many panels in series, so the string voltage exceeds the inverter maximum	Installer must correct the string configuration
2002	DC Arc Fault	String cables arcing or in poor contact	Do not touch. Contact installer.
2011	String Reversed	A string is connected with reversed polarity	Installer must correct it
2051	Abnormal Residual Current	Insulation to ground dropped while operating	Occasional: recovers. Frequent: installer checks strings.
2062	Low Insulation Resistance	Short circuit to ground, or damp conditions with poor insulation	Wait and see. If it returns, installer checks strings.
2080	Abnormal PV Module Configuration	Panel or optimizer configuration does not meet requirements	Installer must check
2081	Optimizer Fault (Warning)	An optimizer is faulty	Installer checks the optimizer details

Low insulation alarms on wet mornings are a known pattern, since Huawei names damp conditions as a cause. Even so, a recurring 2062 should be checked by a professional, because it can also mean damaged cable insulation.

Battery and backup alarms

ID	Alarm	Cause, according to Huawei	What you do
2068	Battery Abnormal (Minor)	Battery faulty, disconnected, or its breaker is off; communication or port voltage abnormal	Check the battery's switch is on. If the fault indicator is lit, contact the battery supplier.
2077	Off-grid Output Overload	Backup output overloaded or short-circuited	Switch off large loads on the backup circuit
2082	Grid-tied/Off-grid Controller Abnormal	Inverter cannot communicate with the Smart Backup Box, or the box is faulty	Follow the manual's restart order, then contact installer

Internal and communication alarms

ID	Alarm	Cause, according to Huawei
2063	Overtemperature (Minor)	Poor ventilation or ambient temperature too high
2064	Device Fault	An unrecoverable fault on a circuit inside the inverter
2065	Upgrade Failed or Version Mismatch (Minor)	A software upgrade did not complete
2067	Faulty Power Collector	The smart power sensor (meter) is disconnected
61440	Monitoring Unit Faulty (Minor)	Flash memory full or with bad sectors

For 2064 and 61440, Huawei says to turn off the AC output switch and DC input switch, turn them on again after 5 minutes, and contact the dealer or Huawei support if the fault persists. For 2065, Huawei says to retry the upgrade.

2067 is worth knowing: the inverter may produce fine, but it cannot see your home's consumption. That gives wrong consumption and grid figures in the app.

Alarm or just offline?

An empty FusionSolar app is not an inverter alarm. It usually means the Smart Dongle lost its Wi-Fi connection. See How to set up the Huawei FusionSolar app for the dongle indicator table and reconnection steps.

When an alarm keeps returning

Note alarm ID, date and time. FusionSolar also keeps an alarm history.
Note the weather. Did it happen in rain, frost or strong sun?
Check whether neighbours had a power cut.
Contact your installer with the details. Huawei's manual ends with the same advice: contact your dealer if the steps above do not solve it.

FAQ

What does alarm 2032 Grid Failure mean on a Huawei inverter?

Huawei's manual lists two causes: a power grid outage, or the AC circuit being disconnected or the AC circuit breaker being off. Check whether there is a power cut and whether the inverter's AC breaker is on.

Is Low Insulation Resistance (2062) dangerous?

It means the inverter has measured poor insulation between the PV array and ground, for example a short circuit to ground or damp conditions. It is a protective shutdown. Do not touch DC cables; if it keeps returning, an electrician or your installer must check the strings.

Can I reset a Huawei Device Fault myself?

For 2064 Device Fault, Huawei's manual says to turn off the AC output switch and DC input switch, turn them on again after 5 minutes, and contact the dealer or Huawei support if the fault persists. Only use switches your installer has shown you.

What is the difference between Major, Minor and Warning alarms?

According to Huawei, Major means the inverter shuts down or functions abnormally, Minor means some components are faulty but it can still generate power, and Warning means it works but output is reduced by external factors.