Well Pump Keeps Tripping the Breaker? 9 Causes and a Quick Troubleshooter
You go to fill a glass and nothing comes out. Down in the basement or at the panel, the well pump breaker has tripped again.
A breaker trips to protect your pump and your wiring, so it is a warning, not just a nuisance. This guide shows the usual causes in plain English, with a troubleshooter to narrow them down and clear advice on what you can check yourself.
Important: well pumps run on high voltage, and many run at 240 volts. Turn the power off at the breaker before opening any cover, and leave panel and in well work to a licensed electrician or pump installer.
Breaker trip troubleshooter
Breaker trip troubleshooter
Answer two questions to see the most likely causes, what you can safely check and when to call a pro.
Why a well pump trips the breaker
A breaker trips when the circuit draws more current than it should, or when current leaks to ground. Your pump motor, its wiring, the pressure switch and the control box all sit on that circuit.
The timing of the trip is your best clue. A trip the instant you reset points to a short, while a trip after long running points to heat.
| When it trips | Most likely causes | First step |
|---|---|---|
| Instantly on reset | Shorted wire, failed splice, burnt motor, water in a box | Stop resetting and call a pump installer |
| When the pump starts | Jammed pump, failed capacitor, low voltage, weak breaker | Listen for humming at the control box |
| After running a while | Overheating motor, low voltage, low water level | Check for leaks that keep the pump running |
| After a storm | Lightning or surge damage, water ingress | Have the control box and motor tested |
| Randomly | Burnt switch contacts, short cycling, loose wiring | Check the pressure switch and tank charge |
9 common causes, from easy to serious
1. Burnt pressure switch contacts
The pressure switch turns your pump on and off thousands of times a year. Over time its contacts pit and burn, which causes arcing and heat.
With the power off, lift the switch cover and look. Blackened or pitted contacts, or ants and insects inside, mean the switch needs replacing.
See our pressure switch settings guide before you fit a new one.
2. Short cycling
If the pump clicks on and off every few seconds, each start draws a surge of current. That wears the motor and can trip a tired breaker.
The usual cause is a pressure tank with too little air. Check the charge with the system drained, then follow our well pump short cycling guide.
3. Water or corrosion in a box
Rain, flooding or condensation can get into the wellhead, a junction box or the pressure switch. Wet connections leak current to ground and trip the breaker.
Look for rust, green corrosion or standing water. A tight, insect proof well cap keeps the wellhead dry, and our well cap guide shows good options.
4. Failed capacitor or relay in the control box
Three wire pumps have a control box above ground with a start capacitor and relay. When they fail, the motor hums, struggles to start and overheats.
These parts are low cost, but capacitors can hold a charge after the power is off. Let a professional test them, and learn the difference in our 2 wire vs 3 wire well pump guide.
5. Low or unstable voltage
Pump motors need voltage within about 10% of their rated value. Low voltage makes the motor draw more current and run hot, which trips the breaker.
Long wire runs, undersized wire and a weak supply all cause it. An electrician can measure voltage at the pressure switch while the pump runs.
6. Motor overheating
A motor that never gets a rest, or pumps air from a low water level, overheats. Hidden leaks, a running toilet or an irrigation zone left open keep it running nonstop.
If taps spit air, the water level may be dropping below the pump. That needs a pro to check the well, and our well flow rate guide explains what they will measure.
7. Pump jammed by sand or scale
Sand, silt or mineral scale can jam the impeller. The motor then draws locked rotor current as it tries to start, and the breaker trips within seconds.
Sand or cloudy water at the taps is a strong hint. The pump has to come out, and a sediment filter afterwards protects your fixtures; see cloudy well water causes.
8. Damaged wire or splice down the well
The drop cable and its splice live in water for years. Rubbing against the casing or a poor splice can break the insulation and cause a short to ground.
An installer tests this with a megohmmeter at the wellhead, without pulling the pump first. Low readings point to the cable or the motor.
9. A worn or wrong size breaker
Breakers weaken after many trips, and an undersized breaker trips every time the motor starts. Only an electrician should check the breaker against the pump nameplate and wire size.
What you can safely check yourself
- Turn off the breaker before you open any cover, and keep it off while you look.
- Check the pressure switch for burnt contacts, insects or water.
- Check the pressure tank air charge with the system drained.
- Look for leaks, running toilets or open irrigation that keep the pump on.
- Look at the wellhead and any junction box for water or corrosion.
- Note when the breaker trips and what you hear, because it saves a pro time.
Anything beyond these checks means working inside a live panel or down the well. That is a job for a licensed professional.
When to call a pump installer
Call a pro if the breaker trips the moment you reset it, you smell burning, the pump hums without pumping or you see sand in the water. Do the same if the problem started after a storm.
Repairs range from a low cost switch or capacitor to a new pump and wire. Our well pump replacement cost guide shows what to budget, and signs your well pump is going bad helps you judge its age.
How to stop it happening again
- Keep the pressure tank charged and check it once a year.
- Fit a pump protection device that shuts the pump off on dry running or low voltage; see well pump protection devices.
- Add a lightning arrestor or surge protection at the control box.
- Replace a pitted pressure switch before it fails completely.
- Fix leaks fast, because a pump that never rests runs hot.
Planning ahead for outages too? See our guides to a battery backup for a well pump and the best generator for a well pump.
Frequently Asked Questions
Why does my well pump keep tripping the breaker?
The most common causes are burnt pressure switch contacts, short cycling, water in a connection, a failed control box capacitor, low voltage or a damaged wire or motor. When it trips is the best clue to which one.
Is it safe to keep resetting a well pump breaker?
No, a breaker that keeps tripping is protecting the circuit from a fault. Resetting it repeatedly can damage the motor or wiring, so find the cause first.
Can a bad pressure switch trip a breaker?
Yes, burnt or pitted contacts arc and heat up, which can trip the breaker. Replacing the switch is a low cost repair once the power is off.
Can a bad pressure tank cause the breaker to trip?
Indirectly, yes. A tank with too little air makes the pump short cycle, and the constant starts can trip a weak breaker and overheat the motor.
How do I know if my well pump motor is bad?
A pump installer tests the motor windings and insulation from the wellhead with a meter. A breaker that trips instantly, a humming pump or a burning smell are common signs.
Does a well pump need its own breaker?
Yes, a well pump normally has a dedicated breaker sized to the pump and the wire. An electrician should confirm the breaker matches the pump nameplate.
