Perkins generator controller shows E021 and indicates earth fault / ground fault

Safety: Ground faults can be hazardous. Only qualified personnel should work on live power circuits. Isolate the generator and lock out before testing.

• Visual inspection: Examine the alternator terminal box, busbars, and outgoing cables for signs of tracking, burn marks, or damaged insulation.
• Insulation resistance test: With the generator isolated, use a megohmmeter to test insulation resistance between each phase and earth, and neutral to earth. Compare readings to manufacturer minimums.
• Check for moisture: Look for condensation or water ingress in the alternator and junction boxes. Dry components thoroughly and improve sealing if necessary.
• Neutral‑earth bond: Verify that neutral‑earth bonding is configured as per system design. Incorrect bonding can cause nuisance earth fault trips.
• Repair or replace damaged components: Replace any cables or alternator components with low insulation resistance. Serious alternator faults may require rewinding or replacement of the alternator stator.