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ErrorLib — Industrial Fault Code Library

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3520

Insulation fault has occurred and has been fixed

SMA · SUNNY CENTRAL 500CP XT / 630CP XT Solar Inverter

What does 3520 mean?

An insulation fault was detected but has since been rectified. This message serves as an informational warning that an insulation event occurred. No further corrective action is required if the fault has truly been fixed.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Verify current insulation resistance (Riso) values for all connected PV strings against manufacturer specifications.

  2. 2

    Inspect all DC cabling, PV module backsheets, junction boxes, and connectors for physical damage or signs of moisture ingress.

  3. 3

    Review inverter historical event logs and operational data for the context and duration of the reported insulation fault.

  4. 4

    Check the integrity of the grounding system for the PV array and inverter, ensuring all connections are secure.

  5. 5

    Verify stable inverter operation and expected power output, monitoring for any recurrence of insulation-related warnings.

Browse all codes in this manual (29)
Verified technical data. Last updated: April 2026

Related Faults

0103*Grid voltage is too high (redundant monitoring)0104*Grid voltage is too high (standard monitoring)0203*Grid voltage is too low (redundant monitoring)
Source: SMA SUNNY CENTRAL 500CP XT / 630CP XT Solar Inverter
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