A pool pump tripping its circuit breaker and you don’t know why? In this article, we’ll give you the full breakdown of how to troubleshoot and fix a faulty pool pump that keeps tripping its circuit breaker.
Circuit breakers for pool pumps trip when the current rating that the pump circuit draws exceeds that of the breaker. The most common reasons for a pool pump circuit breaker to trip are an overloaded motor, underrated pump breaker, bad motor windings or other earthing issue, moisture in the motor or moisture in the wiring.
To find out the more specific and common causes for a pool pump to trip its breaker, and how to stop this from happening keep reading.
Top 10 Causes for Your Pool Pump to Trip the Breaker or GFCI
A quick disclaimer: pool pumps and working with power is potentially deadly. Anything suggested here should be done by a qualified electrician.
That said, here are the top causes for your pool pump to trip the breaker.
1. Water or Moisture is Getting into the Motor
Yes, although a pool pump’s job is essentially moving water, the electrics and the motor cannot get wet. If you notice that the breaker trips after it rains, it’s likely that your problem is caused by water getting into the pump. If moisture gets inside the motor’s coil, it can short and trip the circuit breaker.
To fix this, you’ll need to let the pump dry out completely. You can speed up the process by opening the pump housing and using a heat gun or hair dryer. Make sure you switch the pump off at the breaker first.
To prevent the problem recurring, try covering your pool pump to better protect it from the elements, and ensure that there’s no water pooling around it when it rains. Hopefully, that fixes your problem.
2. Dust and Debris Getting Inside the Motor
Anything that makes your pool pump motor work harder can cause it to overheat, and if it is getting too hot, it will trip the breaker. Too much debris or dust building up inside the motor will do exactly that.
It’s very easy for your pool pump to collect a lot of dust, especially if you’re in a windy location, and when the pump’s housing clogs up, the motor has to work harder. When the pump motor is working harder it draws more current.
Ultimately, an overworked pump can exceed the current limit on the breaker which and when this happens, it will trip. You might have experienced something similar when running too many appliances at the same time.
To fix this issue, firstly switch off the pump at the breaker. Now grab a brush and vacuum and make sure all the air vents on the motor housing are clear. Clean and dirt, dust, debris from around the pump so it doesn’t get into the motor.
If the dust is particularly bad, you can open up the motor housing and vacuum it using a brush to dislodge any dust.
3. The Windings in the Motor Are Bad
Motor windings do go bad and when they do they cause a short circuit and this trips power breakers. I’ve had this problem many times when I worked as a technician.
After a certain age, the insulation around the pump’s motor windings starts to break down and wear off. And when that happens, the windings cause low resistance which means the motor draws too much current.
Too much current draw means the power breaker trips.
To check this, you’ll need a multimeter or Ohm meter. Turn the pump circuit breaker off, disconnect the wiring to the motor. Now measure across the terminals of the motor. You may need to open the motor housing too so you can measure directly on the terminals.
Very low resistance or no resistance can mean the windings are faulty. Sometimes this is hard to diagnose without swapping the motor.
4. Underrated Power Circuit or Breaker to the Pump
It’s possible that the wiring and circuit breaker or GFCI are rated too low to cope with the power demands of the filter pump. If this is the case this could cause the circuit breaker to trip or the fuse to blow.
This can happen if the pump has been replaced with a larger one than the original. Or it’s possible that the original wiring and breaker was installed incorrectly and isn’t large enough for the motor.
You can check the circuit breaker amperage (current) rating yourself. Go to the power board and read the writing on the breaker to the pump. You’re looking for the current rating and it will be something like 20A or 20 amps. Most pool pumps will need a 20-30 amp circuit breaker.
5. Old Wiring Between the Breaker and the Pump
Having old and aged wires is another reason that your pool pump circuit breaker is switching off.
As the wires age, the insulation can break down. And when this happens, the power can leak between the different wires. And the problem is worse if there is moisture – water conducts electricity.
You’ll need an electrician to sort this one out for you.
6. The Wiring Terminals Aren’t Tight
When setting up your pool pump, you need to make sure that the wires have enough contact area for a good connection with the breaker. It means that the wires should be making first and solid contact with the terminals. The terminals should be tight.
Never tighten terminals without confirming there is no power to them – you could easily kill yourself if you don’t know what you’re doing. Best let an electrician check this for you. And use a high quality insulated electrician’s screwdriver.
7. Worn Pump Bearings
Faulty bearings can cause the circuit breaker to trip as the pump has to work harder when the bearings aren’t turning freely.
As pumps get older, the bearings wear and tighten up making it hard for the motor to spin. When this happens, the pump gets hotter and draws more power to try to spin. If the current the pump is drawing exceeds the rating of the circuit breaker, the breaker will trip.
To check this, turn the impeller by hand. The shaft should spin freely. Make sure you turn the pump off at the breaker before you do this.
8. Jammed or Stuck Impeller
Impellers can sometimes get jammed up or stuck completely. A jammed impeller means the motor draws more current overloading the circuit which then causes the circuit breaker to trip.
To stop the circuit breaker tripping and get your pump working again, open up the pump housing and inspect the impeller. It should spin easily. Check for debris such as leaves or other things that shouldn’t be there.
If there is a blockage, clear it out, reassemble the pump, turn the breaker back on and restart the pump.
9. Blockage in the Suction Side of the Pump
If there is a blockage on the suction side of the pump it will need to work harder. The blockage could be in the skimmer box or in the pipes between the skimmer box and the suction side inlet of the pump.
If the blockage is in the skimmer box, with the pump off, take out the basket and clear it out. Pull out any debris inside or near the pipes and retest.
If you still suspect a block, you could try using a drain jet putting the end of it inside the pump. The drain jet expands in the pipe and forces water to it, hopefully dislodging anything stuck.
10. Motor Starting Capacity is Bad
Most motors have a large capacitor in them to get the motor started. It’s common for these to go bad. And when the motor starter capacitor is bad, sometimes it can cause the power to trip.
One sign that this could be an issue is if when you switch on the pump it hums and doesn’t turn – then trips the power and stops. Before you swap this part, make sure there are no blockages in the impeller and that the main shaft of the pump turns easily.
The location of the capacitor is different on different pool pumps. You should check your pool pump’s guide to locate the capacitor. It’s usually on the electrical end of the motor, under a cover.
Make sure you discharge the capacitor before working on it as it can hold charge and give you a deadly shock. Again, this is best left to a qualified electrician.
Sometimes, you can tell if a capacitor has gone bad by just looking at it. If the top part of the capacitor is swollen or has burn marks it may be faulty.
Other times you can measure the resistance. To do this, disconnect it. Change your multimeter setting to ohms and connect the probes of your digital multimeter to the terminals of the capacitor. If the reading of the multimeter is 0 Ohms, there could be an issue. Replace the capacitor and then try the motor again.
You can get motor capacitors here:
What Else Could be Causing The Circuit Breaker to Trip?
In most cases, if your pool pump is constantly tripping the circuit breaker, it will be because of a bad motor or blockage.
These problems are now fairly complex, and we advise you to get an electrician around to have a look at your pool pump. They should be able to tell you what’s wrong with the pump, fix wiring issues or point you in the right direction.
Related Reading: What Gauge or Thickness Wire Does a Pool Pump Need?
How to Troubleshoot Pool Pump that Trips the Breaker
We don’t recommend you try to troubleshoot a pool pump on your own. The best option is to call a qualified electrician. Pool pumps are electrical machines and can cause some serious harm if you don’t know what you’re doing. Any loose or exposed wires can electrocute you. So, don’t try to do it on your own.
With that out the way, we covered the reasons why your pump might trip the power above. Here’s the steps to begin troubleshooting your pool pump:
1. Make sure the pump is primed:
Whenever a pool pump is closed or not filled with water, it gets filled with air. Before beginning to troubleshoot, you’ll have to get rid of the air trapped inside by blowing it out with water. This process is called priming the pump.
Here’s how to do it:
1. Turn off the power. Disconnect the pump from the power source, and make sure that the power button is in the off position.
2. Turn the multiport valve to the “recirculate” option.
3. Find the air valve on top of the pool filter and turn the valve anti-clockwise to relieve the air pressure.
4. Clean the pump box basket. Make sure there’s no debris inside the basket, and rinse it out with water.
5. Fill the pump with water (where the pump basket is). You should fill it up all the way to the top of the basket.
6. Put the lid back on the pump and make sure it’s tightened and sealed.
7. Turn the power on and check if the water is constantly flowing.
8. Once the water is constantly flowing, close the air valve by turning it clockwise. Make sure it’s tight for a good enough seal.
2. Disconnect the motor from the pump:
You’ll need to identify if the problem is with the motor or the pump itself. Disconnect the bonding wire that runs from the circuit board to the motor. It’s just a matter of taking off the screw that connects the bonding wire to the motor.
You need to disconnect it first because it’s a very thin wire and can break easily when isolating the motor from the pump. Again, make sure the main power source is off.
Now, split the pump from the motor. Most pumps are connected to the motor by a clamp, so you can just turn it and disconnect the pump. Others are bolted to the motor, so you’ll need a wrench to take those out.
Once the pump is disconnected, put the bonding wire back on the motor, and turn it on. If the breaker still trips, this will confirm that the problem is with the wiring of the motor, not the actual pump.
If it doesn’t trip the breaker, then you’ll know that the problem is with your pump.
3. Measure the resistance of the pump motor:
If you see the circuit breaker tripping even after disconnecting the pump from the motor, the next step is to measure the resistance of the motor.
To do this, get a digital multimeter. Take the top electrical covering of the motor using a screwdriver. Set the multimeter to Ohms or Resistance, and place its probes on the terminals (L1 and L2).
These terminals are usually labelled on your motor, so they should be easy to find. Again, USE EXTREME CAUTION. CONSULT AN ELECTRICIAN IF YOU’RE NOT EXPERIENCED. You should wear rubber gloves because these wires have 240v on them.
If the reading of the circuit’s resistance is below 1 Ohm it could be too low which means the circuit breaker will trip.
A high reading, over 1 Kilo Ohm could indicate the windings of the motor have gone open circuit – this wouldn’t usually cause a breaker to trip though. The motor just wouldn’t start.
4. Other Troubleshooting Steps:
Once you’ve completed the discussed troubleshooting steps, you can confirm if there’s something electrically wrong with your pool pump or its motor. If these steps didn’t identify the problem, you should move onto some non-technical troubleshooting. Here’s what else you can check:
- Check for any blockages that can overload the pump. Check inside the pipes and the pump box basket. Make sure it’s free from any sort of blockages.
- Check the pipes and the pump box for any kind of wear and tear that could be causing the air to leak.
- Check the bearings and shafts to make sure they’re freely spinning.
Hopefully, this article will help you to troubleshoot your pool pump and fix the issue of circuit breaker tripping. Whenever you’re following any of these steps, it’s very important that the power is switched off at the breaker.
Make sure your pool pump is well-maintained and free from any blockages. We always recommend consulting an experienced electrician before proceeding with troubleshooting steps that involve electricity.