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ISO Over Limitation

Fault Reasons: Inverter detected the impedance of PV+ and PV – to the ground is too low (STS<50KΩ,STT<100KΩ).

Probable Causes:
1. The validity of the grounding of the PV panel frame and bracket;

2. The insulation of PV panel itself;

3. The insulation of DC cables;

4. Whether the head of DC connecters is watered;

5. The humidity of the weather influenced(frost or rainy);

6. The inverter self-detection problem;

1. Check the grounding of the PV panel’s frame and bracket and make sure the impedance to the ground is less than 10Ω;

2. Swap to insert the PV string into DC connectors one by one in turn until all PV strings have been tested in all DC connectors,if one PV string reports this fault in all DC connectors, this PV string may have the above-described problem, and vice versa;

3. Use a multi meter to measure if there’s voltage between the N and PE cable;

4. If the above steps have been checked and excluded, please contact sunways after-sales team at service@sunways-tech.com or +86 400 9922 958 for help.


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