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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.

456

Anti-islanding function is no longer implemented correctly

Fronius · Symo Advanced Manual

What does 456 mean?

A malfunction has occurred in the inverter's anti-islanding protection mechanism. This critical safety function ensures the inverter disconnects from the grid during power outages to protect utility workers.

Common Causes

  • Internal fault in the anti-islanding detection circuitry
  • Software error affecting the anti-islanding algorithm

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    If this status code is displayed all the time, notify a Fronius-trained service engineer.

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 43)Search more codes in this manual