The Arc-Fault Circuit Interrupter (AFCI) mechanism is compliant with NEC code section 690.11, UL1699B and UL1998 standards. Arc fault detection is performed to detect series arcs within the PV array.

The detection algorithms work based on both voltage and current. When an arc fault is detected, Powerwall+ stops converting power and disconnects from the grid. Once a fault has been detected, it can only be reset manually on-site using the mobile app via remote command. The reset cannot be automatically cleared. The fault is displayed with an LED visual indicator, which cannot be reset automatically.

To activate the AFCI self-test feature, power cycle the unit.