Arc-Fault Circuit Interruption (AFCI) Instructions

Solis inverters utilize a software-based AFCI function designed to detect electrical arc-faults on the DC side of the system. The AFCI function is automatically enabled once a US grid standard is selected. While it can be manually disabled in the "Special Settings" submenu, this is not recommended due to the increased risk of electrical fires.

General Guidelines:

• Always Enable AFCI: For rooftop PV systems, AFCI should always be enabled.
• Ground-Mount Systems: AFCI may be disabled if permitted by the local Authority Having Jurisdiction (AHJ).

Detection and Response:

• When an arc-fault is detected, the inverter will shut off, displaying an alarm code such as "AFCI Fault."
• If the occurrence is brief, the fault will auto-recover to minimize false trips.
• If the inverter detects the arc five times, it will shut down completely.

Recovery Steps:

1. Clear the Alarm: Hold the Escape button for three seconds to reset the inverter.
2. Check Alarm History: Access the "ADVANCED INFO" section to review the alarm history:
   • Enter the password 0010 or use the sequence DOWN DOWN UP DOWN.
   • Select "ALARM MESSAGES" to view details of the incidents.
3. Isolate the Fault: To determine if the fault lies within a specific string or inverter:
   • Measure resistance values in between each of the strings + and - and and also each of them to gnd, share the values with Solis support.
   • Disconnect all strings except one and protect it from arcing to the inverter using wire nuts and tape.
   • Run the inverter with each string individually to identify the source of the fault.
4. Inspect System Components: Check every DC connection, including those between modules. Replace any failing components instead of just reassembling them.
5. Conduct a Due Diligence Check: Replace field-made DC connectors, remake connections inside junction boxes, and re-terminate inverter DC connections. Inspect modules for damage or abnormal coloring.

ARM Note:

If the alarm code indicates to check the communication line between the ARM and AFCI, note that the ARM refers to a board within the inverter. This component is not easily accessible for customer checks, as it is buried deep within the inverter. For any issues related to the ARM, it is recommended to contact Solis for further review and assistance.

Additional Considerations:

• If you've followed the AFCI troubleshooting guide and still encounter issues, consider reaching out to the after-sales service for further assistance.
• If the problem persists despite firmware updates, an RMA may be necessary for detailed inspection.