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ErrorLib — Industrial Fault Code Library

Disclaimer: ErrorLib is an independent technical reference tool. While we aim for accuracy, always verify with the manufacturer’s official service manuals before performing maintenance on industrial equipment. ErrorLib is not affiliated with the brands listed.

502

Insulation error on the solar modules

Fronius · Symo Advanced Manual

What does 502 mean?

An insulation error has been detected on the solar modules. This indicates a potential leakage path from the DC voltage to ground, triggering a warning message for safety.

Common Causes

  • Degradation or damage to the insulation of DC wiring from solar modules
  • Moisture ingress into PV connectors or junction boxes
  • Ground fault within a solar module

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    If this status code keeps recurring, contact your system engineer to perform insulation resistance tests on the solar module wiring.

Browse all codes in this manual (60)
Verified technical data. Last updated: April 2026

Related Faults

102AC voltage too high103AC voltage too low105AC frequency too high
Source: Fronius Symo Advanced Manual
Open Manual (Page 44)Search more codes in this manual