Step-by-Step Fix:
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1*Safety First:** Disconnect the AC power to the inverter and the DC disconnect between the battery cabinet and the inverter. Verify zero voltage at the DC bus using a calibrated multimeter before proceeding. Follow NEC 690.15 rapid shutdown requirements.
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2*Visual inspection:** Carefully inspect all wiring, connectors, and battery modules within the cabinet for signs of damage, corrosion, or moisture. Pay close attention to areas where wires pass through metal enclosures.
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3*Insulation Resistance Test:** Using a megohmmeter (insulation tester), measure the insulation resistance between the DC bus (positive and negative terminals) and the cabinet's grounding point. A low resistance reading (below manufacturer's specification, typically >1 MΩ) indicates a leakage path.
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4*Component Isolation:** Disconnect individual battery modules or strings (one at a time) and repeat the insulation resistance test to isolate the source of the leakage current. Note: This should only be done by a qualified electrician.
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5*Grounding Verification:** Ensure a secure and properly sized grounding conductor is connected between the battery cabinet and the system ground. Verify the ground impedance using a ground impedance tester. The impedance should be as low as possible, ideally less than 0.5 ohms as per NEC 250.
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6*BMS Diagnostics:** Consult the Signature Solar battery cabinet's manual for specific diagnostic procedures related to leakage current. Some BMS systems have built-in diagnostic tools to pinpoint the source of the leakage. Check for firmware updates for the BMS, as they may contain fixes for false alarm triggers.
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7*licensed technician Repair:** If the source of the leakage current is traced to a faulty battery module or internal component, replace the defective part with a manufacturer-approved replacement. This work MUST be done by a qualified installer.