The inverter triggers the 3x6b fault code when it detects anomalies in communication with the LG RESU battery or when safety thresholds are breached. This can occur due to insulation resistance (RISO) measurements falling below acceptable levels, indicating potential grounding issues. The battery management system (BMS) is designed to protect the battery from conditions that could lead to damage, such as overvoltage or undervoltage, as well as temperature extremes. If any of these parameters exceed the set limits, the inverter will initiate a protective response, resulting in the fault code.