The internal DC bus voltage inside the inverter has risen above its maximum limit.
Common causes
PV input voltage too high under cold conditions (Voc rise)Grid disconnect event causing bus voltage spikeInternal component failure
What to check
STEP 1
Check PV string open-circuit voltage at inverter DC terminals -- particularly on cold mornings. If Voc exceeds inverter max, string design needs revision
STEP 2
Power cycle. Check ShinePhone for any preceding Error 307 (anti-islanding) event
Escalate if
PV voltage within spec and fault recurs -- internal component issue, escalate
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