Controller shows E11, generator shuts down and will not restart until code is cleared

Safety first: Ensure the ATS has transferred to utility and the generator main breaker is open. Lockout/tagout if required. Use appropriate PPE when working on live circuits.

• Step 1 – Inspect main breaker: Check if the generator main breaker has tripped. Reset it once. If it trips immediately with no load connected, the breaker or alternator may be faulty.
• Step 2 – Isolate loads: With the generator off, open downstream breakers in the ATS or load center. Start the generator and close its main breaker with no load. If it holds, reintroduce loads one circuit at a time to identify a problematic branch.
• Step 3 – Check for obvious shorts: Inspect wiring from the generator output lugs to the ATS for signs of damage, burning, or rodent chewing. Repair or replace damaged conductors.
• Step 4 – Test alternator windings: A technician should perform insulation resistance and winding resistance tests on the alternator stator and rotor. If readings are out of spec, alternator repair or replacement is required.
• Step 5 – Clear code: After resolving the cause, clear E11 on the controller and perform a full‑load test to confirm stable operation.