Generator shuts down with 'Overload' alarm when large loads are applied or during transfer; may trip the generator main breaker.

Safety: Open the generator main breaker and the transfer switch. Confirm that the generator cannot start automatically while troubleshooting.

• Reduce load: Identify and turn off high-demand appliances (HVAC, electric water heater, electric range) at their breakers. Attempt to restart the generator and transfer with reduced load.
• Inspect transfer switch: Check the Generac automatic transfer switch (ATS) for signs of overheating, welded contacts, or loose lugs. If the contactor is stuck closed or damaged, replace the contactor or ATS assembly.
• Check for shorts: With the generator isolated, use an ohmmeter to check for low-resistance faults between hot legs and neutral/ground on the load side. Repair any damaged wiring or appliances causing the fault.
• Test generator breaker: If overload occurs at modest loads, the generator main breaker may be weak. Replace it with the correct Generac-specified breaker rating.