Unequal positive and negative current

On a DC output circuit, the current on the positive conductor and on the negative conductor should be the same. If they differ, the system may have a fault. Check it with the system running at maximum power. Use a DC clamp-on meter set to DC amps and zeroed before each reading, and clamp the positive and negative conductors in the combiner box. The combiner box is opened while under load, so put on the PPE that matches the fault hazard before you take the readings. A ground fault is the failure linked to this pattern. Current takes a path through metal parts that are normally not live, such as the racking, instead of returning only through the positive and negative wires. Typical causes are a module lead pinched between the module and the metal racking, or wire insulation worn by expansion and contraction over a rough conduit fitting. To find the faulted circuit, use a digital multimeter or run an insulation resistance test. Only trained staff should do this work. If the inverter shows a leakage current alarm, disconnect the AC side, open the fuse holders, and add the strings back one at a time until the alarm returns. Then trace that string for a leak to earth ground.

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• sentence 2: support check: partial - The passage supports running the test with the system operating, using a DC clamp meter set to amps and zeroed, and testing both positive and negative in the combiner box. It does not say the system must be at maximum power. It only notes that the system appeared to be operating at maximum power. -->