Generator shuts down; Code 38 displayed indicating overcurrent or short circuit

Safety first: High fault currents are dangerous. Open the generator main breaker and building main disconnect. Do not repeatedly reset breakers without finding the cause.

• Isolate loads: With the generator off, open all downstream breakers in the load panel. Start the generator and close its main breaker. If Code 38 does not appear, close branch breakers one at a time to identify the faulty circuit.
• Inspect transfer switch: Check for welded or burned contacts in the Onan transfer switch. Replace damaged components.
• Check generator breaker: Inspect the generator-mounted breaker for signs of overheating or mechanical failure. Replace if it will not reset or trips at low load.
• Alternator test: If Code 38 occurs with no external loads connected, the alternator windings or internal wiring may be shorted and require professional service.