A running engine does not prove the transfer switch moved or generator output is available. Keep hands out of transfer equipment. Look at the generator breaker position through its access panel without opening cabinets. Check the external indicators on the transfer switch; do not open it.
What this covers
- Residential automatic standby generators running without supplying connected circuits
What it does not cover
Differential
Likely causes of “Generator runs but the house does not receive backup power”, and how to tell them apart
- 1
The generator breaker is off or tripped
What separates it The engine runs and the controller shows normal, but the house has no power, and the breaker on the generator is in the OFF position.
How to confirm Look at the generator breaker position through its access panel without opening cabinets.
- 2
The transfer switch has not moved
What separates it The generator runs but the house stays dark and the transfer switch indicator shows utility.
How to confirm Check the external indicators on the transfer switch; do not open it.
- 3
The utility power has not actually failed or has returned
What separates it The house has power from the utility but the generator runs for a test, or the outage was local.
How to confirm Confirm the utility outage with a neighbor or the utility's outage map.
- 4
An overload or a fault is opening protection
What separates it The generator runs but shuts off its output when loads are added.
How to confirm Remove unnecessary loads and see whether output returns.
Before you touch a setting
Record this first — changing settings destroys the evidence
- The generator breaker position and the controller status.
- Whether the utility outage is confirmed and whether the transfer switch shows a change.
- What loads were running when the transfer failed.
Try in this order
0 of 4 completedCapture the exact state
ReversibleCheck generator breaker position and controller status without opening cabinets.
Separate the likely fault domains
ReversibleConfirm the utility outage, remove unnecessary loads and inspect only external indicators.
Correct only the proven, accessible condition
ReversibleReset a clearly tripped accessible breaker once after identifying cause; transfer testing is professional work.
Verify once before going farther
ReversibleConfirm transfer and retransfer under an authorized controlled test.
Stop boundary
When this stops being a self-service repair
- !Keep hands out of the transfer equipment. Transfer testing and any work inside the transfer switch is professional work.
- !Reset a clearly tripped accessible breaker once after identifying the cause, and confirm transfer and retransfer under an authorized, controlled test.
Evidence ledger
Sources behind this answer
Exact questions
Common questions
The generator is running but the house has no power. Why?+
A running engine does not prove the transfer switch moved or the output breaker is on. Check the generator breaker and the transfer indicators without opening any cabinet.
Why no power to the house?+
The transfer switch may not have switched.