An arc fault nuisance trip happens when the inverter's arc detector reports an arc but no real arc is present in the DC circuit. It can be caused by fast current changes from changing light. At sites with rapid shutdown devices, those devices can also hum during the inverter's MPPT sweep, and the inverter may read that noise as an arc. The inverter logs an arc event, stops feeding the grid, and may stay locked out until someone resets it manually. Never assume a trip is false. Inspect the array before every reset and look for discolored or melted wiring, burned junction boxes, and loose or badly crimped connectors. Where the array cannot be reached, test the cabling with a megohm meter. This finds a fault but does not show where it is. If random arc events affect several inverters at a site with rapid shutdown devices, turning off the ShadeFix sweep can stop the nuisance trips. A firmware update was planned to fix this. If arc events keep recurring, investigate right away. If the cause cannot be found, take the inverter out of service.
caused_byc1 drafted · lead MLPE electronic noise proposed
During the inverter's periodic MPPT sweep (ShadeFix), a rapid shutdown device can be pulled below its threshold voltage and its electronics may hum; the inverter can read this noise as an arc.
sec=h1 h=7f03da2b22dcc2 drafted · lead Inverter parameter settings
Reported when the ShadeFix MPPT sweep parameter is ON, which is the default on most current SMA models.
sec=h1 h=7f03da2b22dcc3 verified · fact Rapid irradiance changes proposed
Fast current changes caused by changing light, combined with a sensitive arc detection circuit, can trip the detector when no arc is present.
sec=h2 h=8d8ea2c308c7verified by: review-workflowverified on: 2026-10-24
affectsc4 drafted · lead Arc fault detection board
sec=h2 h=8d8ea2c308c7review note: support check: partial - u2 mentions the arc detection circuit being triggered falsely, but no passage names a detection board as the affected component; this is only implied.
sec=h1 h=7f03da2b22dctbl=1.r21 h=aa71c3bdef4ec6 drafted · lead Module-level rapid shutdown device
sec=h1 h=7f03da2b22dcreview note: support check: partial - u1 involves RSD devices as the noise source, but being 'affected' by the nuisance trip is not stated.
presents_asc7 drafted · lead Arc fault detected
SMA event IDs 4301/4302/8204/8206/8210 are reported, sometimes at random across several inverters.
sec=h1 h=7f03da2b22dctbl=4 h=121553a4ae2ec8 drafted · lead Spurious fault event
sec=h2 h=8d8ea2c308c7c9 drafted · lead Inverter shutdown
tbl=1.r21 h=aa71c3bdef4etbl=2.r2 h=93b0ffeaef0cc10 drafted · lead Operation inhibited
When AFCI is set with permanent operation inhibition, the inverter waits for a manual reset.
tbl=4 h=121553a4ae2etbl=2.r2 h=93b0ffeaef0ctbl=1.r12 h=9d5e8686b009c11 drafted · lead Inverter audible noise
The humming comes from the rapid shutdown device electronics during the MPPT sweep, not from the inverter.
sec=h1 h=7f03da2b22dcreview note: support check: partial - u1 says the RSD electronics hum during the sweep and the inverter reads it as an AFCI event, but it never lists inverter audible noise as a symptom, and the note that the hum is not from the inverter is only implied.
detected_byc12 verified · fact Visual inspection
sec=h2 h=8d8ea2c308c7verified by: review-workflowverified on: 2026-10-24
c13 drafted · lead Tactile inspection
Gently tug DC cables at connectors and in the combiner box to find loose terminations or bad crimps.
sec=h2 h=8d8ea2c308c7review note: support check: partial - u2 describes gently tugging DC cables to find loose or badly crimped connections, but this finds real faults, not the nuisance trip itself.
c14 drafted · lead Insulation resistance testing
Used on cabling where a hands-on inspection is not possible, such as residential rooftops. It does not pinpoint the fault location.
sec=h2 h=8d8ea2c308c7review note: support check: partial - u2 recommends a megohm meter where hands-on inspection is not possible and says it does not pinpoint the fault, but it frames this as finding a cabling failure, not detecting a nuisance trip.
distinguished_fromc15 drafted · lead Arc fault — told apart by Visual inspection
A real arc leaves evidence such as discolored wiring or racking, melted connectors or insulation, and burned junction boxes. A false trip leaves no such damage and no loose or badly crimped connections.
sec=h2 h=8d8ea2c308c7review note: support check: partial - u2 says arcing leaves evidence that a visual inspection finds, but it does not state that a false trip leaves none.
mitigated_byc16 drafted · lead Inverter parameter adjustment
Set ShadeFix to 'NO' when random AFCI events appear across several inverters at sites with rapid shutdown devices.
sec=h1 h=7f03da2b22dcc17 drafted · lead Firmware update
The manufacturer said a future firmware release would address the condition.
sec=h1 h=7f03da2b22dcc18 drafted · lead Contact system installer
sec=h1 h=7f03da2b22dcc19 drafted · lead Manual reset of latched operation inhibition
Reset only after the array has been inspected.
tbl=4 h=121553a4ae2etbl=1.r21 h=aa71c3bdef4etbl=1.r12 h=9d5e8686b009review note: support check: partial - u9, u13 and u24 support a manual reset of operation inhibition, and u2 requires inspecting the site before resetting, but only u2 links reset to nuisance trips and it is not in the cited passages for this statement.
c20 drafted · lead Close monitoring
Investigate recurring AFCI events at once. If no cause is found, take the inverter out of service.
sec=h85 h=07b9502017dasec=h84 h=b85bcfdc3194leads_to c5