Connector overtemperature

First, watch the inverter for 5 minutes to see whether the alarm clears by itself. If it keeps coming back, contact after-sales service. Fault5020 and Fault5030 report a faulty connector temperature sensor rather than real heating. For those codes, check that the bulkhead connectors are properly connected. The most likely failure mode behind a hot connector is a connector defect. Resistance heating there can lead to arcing, ground faults and fire. These defects usually come from installation problems: poor crimping, mismatched or cross-mated connectors, or low-quality materials. Ageing from UV and humidity is a less common cause. An infrared scan under load usually shows an affected connector as a hotspot at an early stage. Compare string currents as well. Isolate the circuit safely before a visual and hands-on check. Look for melted, burned, brittle, cracked or whitened connectors, and for corrosion inside opened ones.

<!-- review notes

• sentence 1: support check: partial - Passages say observe 5 minutes for automatic clearing and contact after-sales if the alarm still occurs, but 'keeps coming back' is a slight paraphrase and applies to Fault6010/6020 only, which the statement doesn't specify.
• sentence 2: support check: partial - Passages give the check-connection action for Fault5020/5030 but do not say they indicate a faulty sensor rather than real heating (though the names say sensor abnormal).
• sentence 3: support check: partial - Passages say connector defects cause resistance heating, arcing, ground faults and fire, but do not state it is the 'most likely' failure mode behind a hot connector. -->