Troubleshooting
Why Your Well Pump Keeps Tripping the Breaker
The breaker is doing its job. When it trips tells you more than the fact that it trips — and it decides whether you need an electrician, a well contractor, or both.
On this page
A breaker trips when the pump circuit draws more current than it should. On a well system that usually means a fault in the motor, cable or wiring, a pump that can't turn (sand-locked or seized), a start problem in the control box, or a motor that is overheating from low voltage or constant restarts. Reset it once. If it trips again, leave it off — the Electrical Safety Foundation International says frequent trips indicate a problem that should be inspected by a qualified electrician.[1]
One reset, then stop
Each reset sends full current into whatever caused the trip, in a circuit that runs through water. Don't hold a breaker on, tape it, or swap in a larger one. Opening the pressure switch, control box or panel and testing live circuits is work for a licensed electrician or well contractor.
When it trips is the best clue
| When it trips | Likely causes | Who to call first |
|---|---|---|
| Instantly, every time | Short circuit or ground fault in the motor, the drop cable, a splice, or the wiring between the house and the well | Well contractor (they can test the motor and cable from the surface) |
| After a few seconds of humming | Motor can't turn (sand-locked or seized pump), or it can't start (failed start capacitor or relay) | Well contractor |
| After the pump has run a while | Overheating: low voltage, a worn pump or motor drawing high current, or a control box in a hot location | Well contractor; the utility or an electrician if voltage is low |
| Now and then, with frequent pump starts | Short cycling is overheating the motor | Fix the cycling — see short cycling |
| During or after storms | Lightning or surge damage to the motor, control box or switch | Well contractor |
| Right after new work | Wiring error — Square D's bulletin says to check the switch wiring when a breaker trips on a new installation[2] | The installer |
Breaker or overload? They're different things
A well pump has two layers of protection, and people often confuse them:
- The breaker in your panel protects the wiring. When it trips it stays off until someone resets it.
- The motor's overload protector — inside two-wire motors, or in the control box on many three-wire systems — protects the motor from heat. It shuts the motor off and, on many motors, resets by itself after cooling.
So a pump that stops for a few minutes and then starts again without anyone touching the panel is tripping its overload, not the breaker. Franklin Electric lists the causes of "motor runs but overload protector trips" as incorrect voltage, overheated protectors (direct sun or another heat source on the control box), a defective control box, a defective motor or cable, and a worn pump or motor.[3]
The causes, and how a pro confirms each
- Motor or cable fault
- Insulation breaks down with age, heat, lightning or a nicked cable. Confirmed with winding-resistance and insulation-resistance tests from the surface. Franklin's installation checks call for insulation resistance to be measured at 500 volts.[3]
- Bound (sand-locked) pump
- The motor is powered but can't turn. Franklin notes amp readings 3 to 6 times higher than normal until the overload trips.[3] Confirmed with a clamp ammeter; fixed by pulling the pump.
- Control box fault
- On three-wire pumps, a failed start capacitor or relay keeps the motor from starting. See well pump control boxes.
- Low or wrong voltage
- Franklin requires voltage within 10% of the motor's rating.[3] Low voltage makes the motor draw more current and run hot.
- Heat at the control box
- Franklin says the box must not be hot to the touch, and that boxes should never be mounted in direct sunlight or high-temperature locations.[3]
- Too many starts
- A waterlogged tank causes fast cycling, and Franklin notes this can lead to nuisance tripping of the overload on two-wire motors.[3]
- Restart too soon
- Franklin cautions that restarting a motor within 5 seconds after power is removed may trip the overload.[3] After a flicker, give it a moment.
Is the breaker the right size?
Sometimes the breaker itself is mismatched after a pump replacement. For reference, these are the typical circuit-breaker sizes Franklin Electric lists for its 4-inch single-phase submersible motors:[3]
| Motor | Typical circuit breaker |
|---|---|
| ½ HP, 115 V | 30 A |
| ½ HP, 230 V | 15 A |
| ¾ HP, 230 V | 20 A |
| 1 HP, 230 V | 25 A |
| 1½ HP, 230 V | 30 A |
This is a reference for a conversation with your electrician, not a sizing guide: the correct breaker depends on the motor nameplate, the wire size and the electrical code where you live. Never install a bigger breaker to stop the tripping — that removes the protection from wiring that is telling you something is wrong.
What you can safely do
Safe to check
- Reset the breaker once, firmly off and then on.
- Note what happens and how long it takes: instant trip, hum then trip, or runs then trips.
- Look (don't touch) for scorch marks, melted plastic or a burnt smell at the pressure switch and control box.
- Note whether lights dim when the pump tries to start.
- Check whether the control box sits in direct sun or a hot well house.
- Tell the contractor about recent storms, outages or work on the system.
Typical costs
| Repair | Range |
|---|---|
| Motor start capacitor | $150–$300 |
| Control box | $300–$600 |
| Pressure switch | $150–$200 |
| Submersible pump replacement | $1,000–$2,500 |
Ranges are HomeGuide's national figures.[4][5] An electrician's diagnostic visit is extra; the same publisher reports $50–$130 per hour for electricians.
Sources
- Electrical Safety Foundation International (ESFI). Fuse and Breaker Breakdown. Accessed Oct. 8, 2026.
- Schneider Electric (Square D). Preventive Maintenance and Troubleshooting Guidelines for Class 9013F and 9013G Pressure Switches (Data Bulletin 9013DB0701, Dec. 2007). Accessed Oct. 8, 2026.
- Franklin Electric. Submersible Motors: Application, Installation & Maintenance (AIM) Manual, 60 Hz. Accessed Sept. 28, 2026.
- HomeGuide. How Much Does Well Pump Repair Cost? (article dated Aug. 6, 2025). Accessed Oct. 8, 2026.
- HomeGuide. How Much Does a Well Pump Cost To Replace or Install? (article dated Aug. 7, 2025). Accessed Sept. 28, 2026.
We cite manufacturer documentation and public agencies first. Read how we choose and check sources.