AI L2 Under Voltage

What does F38 mean?

This fault indicates an L2 under-voltage condition (66 VAC) detected by the anti-islanding protection, triggering a fast disconnect. This mechanism ensures the inverter disconnects from an unstable grid, protecting both the inverter and grid from potential damage due to critically low voltage.

• Severe and sudden drop in L2-Neutral grid voltage below 66 VAC, indicating a local grid fault, near short-circuit, or complete phase loss.
• Major power system event causing an immediate and critical voltage sag or collapse on phase L2.
• Inverter's L2 voltage sensing circuit experiencing a catastrophic failure or complete loss of signal, leading to an immediate trip.
• Anti-islanding parameter P_AI_L2_Volt_Min_Fast set too restrictively, triggering a fast disconnect even on momentary deep sags.

Click steps to track your progress.

1. 1

   Immediately verify the L2-Neutral voltage at the inverter's AC input terminal L2 using a true RMS multimeter to confirm grid voltage presence.

2. 2

   Check the utility main breaker or local upstream breaker supplying the inverter for a tripped condition, indicating a severe electrical fault.

3. 3

   Inspect the physical wiring connections for the L2 phase and neutral (Terminal L2, Terminal N) at the inverter and upstream disconnects for obvious damage or complete disconnection.

4. 4

   Review the inverter's event log to determine if the voltage drop was sudden and severe, or if other phases were affected simultaneously.

5. 5

   If all external power and wiring appear correct and the grid is stable, the inverter's internal L2 fast voltage sensing circuit may be faulty, requiring service.