Fault family

Isolation fault codes

25 codes across 13 brands whose manufacturer wording names low insulation resistance or an isolation fault between the PV array and earth.

A family groups codes by the manufacturer's wording. It does not mean the codes share a cause, a trip setting or a fix: the same words can describe different measurements on different hardware, so work each code from its own entry and its manufacturer's document.

Codes by brand

Work it on site

Symptom-led sequences and checks that record the evidence for this kind of alarm. Follow the code's own entry for its documented step.

Guided decision trees

Members with a reviewed, step-by-step walk of the manufacturer's own procedure. Each opens on the code's entry.

Standards scope

Scope pages: what each standard covers and where it sits against the others. They do not reproduce the standard, and nothing on this page states what it requires. Work from the current published edition.

How codes are placed here

A code joins only when the manufacturer's own title or description contains one of these terms as whole words. The title decides first; Wattbench's fixes and search keywords are never read. A code that matches no family, or more than one, stays unclassified.

  • insulation resistance
  • insulation impedance
  • insulation fault
  • insulation failure
  • insulation error
  • insulation protection
  • insulation to the ground
  • insulation between the array and ground
  • isolation fault
  • isolation failure
  • isolation fail
  • isolation impedance
  • isolation low
  • iso fault
  • iso resistance
  • not properly isolated from ground
  • isolation
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Answers on fault codes, calculators, AS/NZS scope and current field updates, every one drawn from Wattbench with the source attached. It won’t guess a code or a standard.