Prepare a well-pump generator assessment with the pump, motor, controller, supply voltage, and other outage loads identified. Do not select backup power from a generic household chart alone. This guide lists the information to take to the pump supplier and electrician.
Identify every relevant component
Record the pump and controller models and photograph accessible electrical labels without opening energized equipment. Find the matching manuals. Ask the pump supplier for running and starting requirements where the documentation is incomplete. Mark unknown values as unresolved rather than filling them with another pump’s specifications.
Include other operating loads
Generac’s sizing guidance identifies well pumps as loads that can change a home’s backup requirements and advises a professional load analysis. Keep the pump demand and the other simultaneous loads visible in the assessment. Source: Generac sizing guidance.
Why startup data matters
Generac’s mobile-generator sizing paper discusses motor starting and gives a pump example. Treat that example as an illustration rather than a rating for your installed well system. Ask the installer which data applies to your motor and controller. Reference: Generac motor-load sizing paper.
Your installer worksheet
| Question | Record to bring |
|---|---|
| What is installed? | Pump, motor, and controller model numbers |
| What supply is required? | Manufacturer voltage and electrical data |
| What happens at startup? | Documented starting requirement |
| What else runs? | Other planned simultaneous loads |
| How is it connected? | Electrician’s specified connection equipment |
| How is it verified? | Supervised assessment and handover procedure |
Separate compatibility from duration
A source that can start the pump still needs a plan for the intended outage duration. Ask about fuel or stored energy using the exact backup equipment data. For standby fuel budgeting, keep the units and usage scenario on a separate worksheet rather than treating a capacity label as a runtime statement.
Questions before ordering
- Has the supplier reviewed the exact motor and controller?
- Is the planned output compatible with the required supply?
- Have startup and simultaneous loads been reviewed?
- Who installs and verifies the household connection?
- What alternative covers an unavailable backup source?
Can horsepower alone settle the generator size?
This guide does not verify that shortcut. Obtain the actual electrical requirements and a professional assessment.
For a different pump application, see the sump-pump load checklist.