Quick answer
Turn off sensitive and 240V loads, stop adding load, and record which generator receptacles and transferred circuits work. Check only visible external controls, the exact voltage-selector position, output breaker state, cord and connector damage while de-energized, transfer indicators, and load-management status. Do not open the generator, inlet, transfer switch, or panel. Repeated trips, abnormal voltage, heat, odor, arcing, or partial building power require qualified electrical and generator service.
Map the symptom without opening energized equipment
Record whether one generator receptacle is affected, whether both 120V legs are available at the generator according to approved indicators or tests, whether the condition begins after the cord and inlet, and which transferred circuits remain available. Photograph external breaker, selector, transfer, and controller indications.
Turn off 240V motors, pumps, HVAC, ranges, water heaters, and sensitive electronics until the complete source is verified. A 240V load can receive abnormal or zero line-to-line voltage when one hot leg is missing. Do not use working 120V circuits as proof that the system is safe.
| Observation | Possible boundary | Safe response |
|---|---|---|
| One receptacle section affected | Receptacle or branch protection | Disconnect loads and use manual-approved checks |
| Generator output normal, house partial | Cord, inlet, transfer or panel path | Qualified building-system review |
| All 240V loads fail | Missing leg or wrong selector configuration | Keep 240V loads off |
| Heat, odor, arcing or repeated trip | Damaged high-energy connection | Shut down and keep out of service |
Check only the external configuration and connection labels
With loads removed and the system de-energized as required by the manuals, inspect the cord, L14-30 or 14-50 endpoints, locking engagement, visible pins, cable jacket, and strain relief. Confirm the generator output breaker is fully reset only if the manual permits and the voltage selector is in the required 120/240V position.
Confirm that the cord and inlet carry both hot conductors, neutral, and equipment ground for the intended split-phase path. A 120V-only source or adapter cannot energize a true 120/240V panel. Do not bridge legs to make both sides appear live because multiwire and 240V circuits can be damaged or left unsafe.
Leave breaker poles, transfer contacts, conductors, and windings to qualified diagnosis
A failed breaker pole, loose or overheated termination, damaged cord conductor, inlet fault, transfer contact, selector, winding connection, or alternator fault can create partial power. Confirming those possibilities can expose utility and generator sources even when one source appears off.
Use a qualified electrician for the inlet, transfer, and panel path and model-specific generator service for source output. Provide the symptom map, equipment labels, selector position, breaker and transfer state, connected loads, weather, event timing, and any fault history.
Return loads only after both legs and line-to-line output are verified
Qualified commissioning should verify acceptable line-to-neutral voltage on both legs, line-to-line voltage, frequency, polarity, neutral and grounding arrangement, transfer operation, per-leg loading, and protection. Test with controlled loads before restoring motors and sensitive equipment.
Balance 120V loads within generator per-leg limits and document the approved selector, breaker, cord, transfer, and load sequence. Stop immediately if partial power, abnormal voltage, or heat returns.
Frequently asked questions
Common questions
Why does only half my house work on generator power?
One split-phase leg may be unavailable somewhere in the generator, breaker, cord, inlet, transfer, or panel path. Keep 240V loads off and obtain qualified diagnosis.
Can I connect both panel legs to one 120V generator output?
Do not improvise that arrangement. It can affect multiwire circuits, 240V loads, transfer equipment, protection, and conductor loading. Use an approved design.
Could the generator voltage selector cause partial power?
Yes, an incorrect model-specific selector position can change available receptacles or winding configuration. Change it only through the exact unloaded procedure.
Can I measure both legs myself?
Only a person qualified for the equipment and electrical hazard should perform live measurements using an approved procedure and suitable instruments.
Primary references
CordFind summarizes connector specifications and public safety guidance. Always follow the instructions supplied with your equipment.