Generator display shows E20 and the unit will not accept load even though it is running normally.

Safety first: Ground faults can be hazardous. Turn OFF the generator, isolate it from the ATS, and ensure all circuits are de-energized before inspection.

• Inspect output compartment: Open the generator output terminal box and look for moisture, condensation, or corrosion. Dry thoroughly and correct any water entry points.
• Check output cable insulation: Examine cables from the generator to the ATS for cuts, abrasions, or rodent damage exposing conductors. Replace damaged cables.
• Test loads: At the building panel, turn off all branch circuits, then restart the generator and attempt transfer. If E20 clears, turn circuits back on one at a time to identify the faulty branch.
• Inspect ground fault sensor: If equipped, check the toroidal ground fault sensor and its wiring to the controller. Replace if cracked or water-damaged.

Persistent ground fault indications should be investigated by a licensed electrician to ensure safe operation.