What you may be noticing
- The generator starts and runs normally, but no lights or outlets come on in the house.
- A standby generator runs during an outage, but the transfer switch doesn't seem to change over.
- The portable generator's own outlets work, but the house circuits through the inlet don't.
Common possible causes
Transfer switch in the wrong position
Manual transfer switches have to be moved to the generator position, and individual circuit switches may need to be set as well. It's easy to miss a step during a stressful outage.
Interlock not engaged correctly
With an interlock kit, the main breaker must be off and the generator breaker in the panel on. If either is in the wrong spot, power doesn't reach the house circuits.
Generator output breaker tripped or off
Most generators have their own main output breaker. If it's off or tripped from an earlier overload, the engine runs but nothing leaves the unit.
Inlet or cord connection
A generator cord not fully seated or locked at the inlet box or generator, or a damaged cord, will stop power from getting through.
Automatic transfer switch fault
Standby systems rely on a transfer switch and controls to sense the outage and change over. A control fault, a tripped breaker in the switch or a failed component can leave the generator running without carrying the load.
Generator problem
A generator can run without producing proper voltage due to an excitation, regulator or wiring fault inside the unit.
Safe checks you can make
- Check that the generator's output breaker or circuit breakers on the unit are on.
- Confirm the cord is fully pushed in and twisted to lock at both the generator and the inlet box.
- If you have a manual transfer switch, confirm it's in the generator position, along with any individual circuit switches.
- With an interlock, confirm the main breaker is off and the generator breaker is on, following the labels on the panel. Don't remove any panel covers.
- Plug a lamp directly into a generator outlet to see whether the unit itself is producing power.
What not to do
- Never backfeed the house by plugging a generator into a dryer outlet or wall outlet with a double-male cord. It can energize the utility lines and seriously injure or kill line workers, and can start a fire in the house.
- Don't run a generator in a garage, basement, porch or near windows and doors, even with the garage door open. Carbon monoxide builds up fast.
- Don't open the transfer switch or panel to troubleshoot.
- Don't move switches or connections with wet hands or while standing in water.
Can you sort this out yourself?
Plenty of these situations come down to a switch or breaker in the wrong position, and you can safely check those using the labels and instructions on your equipment. If the lamp plugged straight into the generator works, but the house still has no power with everything set correctly, the problem is in the inlet, cord, interlock, transfer switch or wiring, and an electrician should take it from there. If the lamp doesn't work either, the generator itself needs service.
When professional help is appropriate
- Everything is set correctly and the house still has no power.
- The transfer switch makes noise, smells hot or shows scorching.
- The generator cord or inlet looks melted, cracked or burned.
- Your setup has no transfer switch or interlock at all.
- A standby generator system has stopped changing over automatically.
What an electrician typically checks
An electrician will test the generator's output, the cord and inlet, and the transfer switch or interlock, then trace where power stops. Common fixes include replacing a damaged inlet or cord end, correcting an interlock installation, repairing a transfer switch, or adjusting wiring so the circuits you need are on the generator side.
If the home has no transfer switch or interlock, the electrician can install one so the generator connects safely and legally, with a permit where required. Storm and ice outages around Chattanooga make a reliable setup worth getting right. See generator installation and home generator basics.
Keeping it from coming back
Practice a changeover on a calm day, write the steps on a card near the panel or transfer switch, and run the generator under load periodically. Place the generator outdoors, well away from the house, and keep battery CO alarms working inside.
