AC circuit breaker tripping

An AC trip happens when the AC circuit breaker between the inverter and the grid opens, which disconnects the inverter from the grid. In monitoring this usually shows up as a no-grid or grid-failure alarm on the inverter, with a prompt to check the AC circuit breaker. On some storage systems a breaker status point changes from closed to open. Note when the trip happens: at grid connection, during startup, while generating power, at random, or at a set time. This helps narrow down the cause. One test is to see whether it still trips with power limited to 10% and then 20%. Check the breaker rating first. A breaker that is too small or has built-in current protection can cause nuisance tripping. The rating should be 1.2 times the inverter's maximum AC output current. If the correctly sized breaker still trips, it may have degraded over time. Replace it with a new one of the correct rating to rule out a hardware fault. Inspect the breaker terminals, AC connector, AC distribution board and meter side for loose or damaged wiring. Measure phase-to-phase, phase-to-neutral and neutral-to-earth voltages at the inverter AC gland, so you can catch AC wiring errors such as shorted phases. If the inverter keeps reporting grid failure, the AC cable may be connected wrongly or the country data set may be configured wrongly. This points to a wiring error or a grid code setting problem rather than a breaker fault.

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• sentence 6: support check: partial - Inspection of terminals, AC connector, ACDB and meter side and the voltage measurements at the AC gland are stated, but 'shorted phases' is only loosely backed by the note about customers shorting 2 phases to 3.
• sentence 7: support check: partial - The wrong AC cable connection or country data set cause is stated, but the conclusion that this points away from a breaker fault is not.
• sentence 7: review: partial - The SMA rows give a wrong AC cable connection or a misconfigured country data set as the cause of the grid failure message, but they never say this points away from a breaker fault. -->