This fault is in the inverter's arc detection board, which watches the PV lines for arcing and signals the control board to take the inverter off the grid. When the board fails, the display shows an arc board error and the inverter will not connect to the grid until the board works again. Likely causes are poor contact at the arc board or a damaged board. Some models also report it as a failed internal self-check of the board. First make sure the logic connector to the arc board is secure and the board looks to be in good condition. Then run the Arc Fault Test from the Settings menu, or clear the fault with the ARCFaultClear command. If the alarm comes back, contact the manufacturer's service team to replace the arc board or the wiring box. Do not mix this up with the ARC Protect alarm. That alarm means an actual arc was detected in the PV input.
affectsc1 verified · fact Arc fault detection board
tbl=39.r3 h=99d70367a788tbl=42.r6 h=4ea475188b04sec=4.4.4 h=50f6c0ff2497sec=5.4.4 h=f90171d02e8bverified by: review-workflowverified on: 2026-10-20
The arc detection board sits inside the inverter and passes arc signals to the control board DSP.
sec=4.4.4 h=50f6c0ff2497sec=5.4.4 h=f90171d02e8bverified by: review-workflowverified on: 2026-10-20
caused_byc3 verified · fact Poor connector contact
The listed possible cause is poor contact at the arc board or damage to the board.
tbl=42.r6 h=4ea475188b04tbl=42 h=2a25ca716edfverified by: review-workflowverified on: 2026-10-20review note: support check: partial - Poor contact or damage of Arcboard is a listed cause, but the statement attributes it to generic poor connector contact, which is only partly the same (damage is another cause).
presents_asc4 verified · fact Self-test failure
Reported as an internal arc board self-check error or an abnormal reading inside the arc board.
tbl=18.r3 h=c279ec78fba0verified by: review-workflowverified on: 2026-10-20
c5 verified · fact Inverter shutdown
The inverter stays off the grid until the arc board is working again.
sec=4.4.4 h=50f6c0ff2497sec=5.4.4 h=f90171d02e8bverified by: review-workflowverified on: 2026-10-20
detected_byc6 drafted · lead Inverter display check
The LCD shows 'arc board err'.
sec=4.4.4 h=50f6c0ff2497sec=5.4.4 h=f90171d02e8bc7 drafted · lead Arc fault self-test
Run the Arc Fault Test from the Settings menu. If the alarm comes back, the board is faulty.
tbl=39.r3 h=99d70367a788tbl=10.r3 h=99d70367a788tbl=63.r3 h=99d70367a788review note: support check: partial - Run Arc Fault Test and if alarm re-occurs contact service is stated, but not explicitly that the test is a detection method or that a recurrence means the board is faulty.
mitigated_byc8 verified · fact Board connector check
Make sure the logic connector to the arc board is secure and the board is in good condition.
tbl=39.r3 h=99d70367a788tbl=10.r3 h=99d70367a788tbl=63.r3 h=99d70367a788tbl=42.r7 h=efe8b49b988fverified by: review-workflowverified on: 2026-10-20
c9 verified · fact Arc board replacement
CPS Service replaces the arc board or the wiring box if the alarm comes back.
tbl=39.r3 h=99d70367a788tbl=10.r3 h=99d70367a788tbl=63.r3 h=99d70367a788verified by: review-workflowverified on: 2026-10-20
c10 verified · fact Contact manufacturer service
tbl=39.r3 h=99d70367a788tbl=42.r7 h=efe8b49b988ftbl=18.r3 h=c279ec78fba0verified by: review-workflowverified on: 2026-10-20
c11 drafted · lead Inverter restart
Switch the inverter back on. If the error stays, contact customer service.
tbl=18.r3 h=c279ec78fba0distinguished_fromc12 verified · fact Arc fault — told apart by Inverter display check
'ARC Protect' means the board detected an actual arc in the PV input, and that fault is cleared manually. 'Arcboard Err' means the detection board itself has poor contact or is damaged.
tbl=42 h=2a25ca716edfsec=4.4.4 h=50f6c0ff2497sec=5.4.4 h=f90171d02e8bverified by: review-workflowverified on: 2026-10-20
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