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Hot Tub GFCI - Parts Service and Troubleshooting

The GFCI or Ground Fault Circuit Interrupter is a safety feature that works like a fast responding circuit breaker. 

This safety device monitors the balance between hot and neutral wires in the same power circuit. If there is a ground-fault with current imbalance of about ~ 5 mA or greater, the GFCI will trip which is detected by comparing the current going to and from the spa, the breaker will instantly trip to reduce the risk of electrical shock. 

GFCIs are commonly found in bathrooms for bathroom plugs and also in a house to protect exterior plugs or even Christmas lights.  GFCIs are a safety requirement in the installation of many hot tubs.

Buy a GFCI

Hot tub GFCI installation and repair.Installing a new spa or replacing a defective GFCI?  Hot Tub Outpost offers the most popular complete GFCIs with sub-panel.

The most popular GFCI kits for hot tubs are the 30 amp GFCI, 40 amp GFCI, 50 amp GFCI and 60 amp GFCI with Siemens sub-panel box.  This is usually mounted 6-10 feet from the spa depending on local electric code.

Note: It is a serious code violation and safety issue to not have a working GFCI hooked up to your hot tub!

See our current selection of GFCI load centers, GFCI cords and GFCIs.

Horse Sense
Warning: Working on your own appliances, cars, covered wagons and hot tubs as well as anything else electrical or mechanical carries with it severe risk of injury or property damage. These tips and suggested procedures are free and for informational purposes only. Proceed at your own risk. Use the services of an electrician for any main electrical work including the installation of a GFCI. Hot Tub Outpost is not liable for any damage or injury that may result.

Install a GFCI

Wiring a GFCI is a job for electricians in accordance with county, national or local electrical codes.  Some electricians may however, not get the white wire right, so it pays to inform your electrician about the specific GFCI wiring instructions that came with your spa.  Sometimes there are also GFCI wiring notes in the inside panel of the spa pack / control box. 

Read more about hot tub electrical installation.

Troubleshoot a GFCI

If through an electrical fault of the spa or spa pump or part, electricity is allowed to flow from the ground to you, there is a risk of electrical shock.  Hot tubs without proper GFCI protection run the risk of having the water energized and if you step into or out of the spa, you may get shocked if there is a short circuit in the equipment or heater. 

To test the GFCI, press the test button to ensure power is turned off to the spa. The test is not only done upon installation of the GFCI but also during regular checks of the device to assure it is protecting the spa users properly.

GFCIs will fail if not wired properly, so the electrician must assure the device is correctly installed. Reversing the line and load is an all too common mistake that is made on installation of this device.

If a GFCI trips, then it is important to see if that is a half-trip (short in spa) or full trip (circuit overload).  With power to the spa off, spa technicians will unplug pumps and peripherals from the spa pack to eliminate these components as a source of tripping.  Check the GFCI panel to see if it still trips. If so, the problem may be the spa heater.  The technician will disconnect the heater to see if that is the problem.

Typical spa components that can cause GFCI tripping include a blower that has gotten water in it, the ozonator, the heater with a short or one of the spa pumps or circulation pump.  The heater is often the culprit and the service tech will disconnect the heater wires going to the heater to see if the short is still present.  If the GFCI is still tripping with heater wires removed, then problem may be the pump motor or other issue.



In this case the problem with the GFCI tripping was caused by a short in the heater. 

Nuisance Tripping of GFCI - Randomly

This one is hard to diagnose, because the GFCI does not trip when a piece of equipment comes on such as the heater, pump, blower, ozonator etc.. It just decides to trip after a few hours, days etc.. of normal operation.  This type of tripping is rarely caused by a short to ground such as if equipment had a short circuit.

It could be as simple as a loose wire or connections. If there is a loose connection and the voltage is dropping at the spa, then this dropping voltage will cause the amperage to rise and could trip the breaker after running awhile. Electrician should verify that the connections are tight in box and at the spa. Look for signs of burning on cords. The wire size to the spa should be number 6 and less than 50 feet from the actual house breaker box in length. If you find this not to be true make the spa is set to low current mode 20 amps. There will be a jumper or dip switch to do this on the circuit board. It will turn off the heater when pump(s) are turned on high speed. This will reduce the strain on wires and the GFCI but also does not allow for heating when the pumps are on high speed.
After the spa runs for a little while feel the front of the gfci it should not be heating up. If it is you need to make sure those connections are tight - you may need a new gfci.

Another possibility of random tripping of the GFCI is the nuisance trip. This happens when a GFCI in a sub panel is wired wrong. It can start happening anytime and stop again whenever (ie. random). Even after five years, it could just start happening, It happens when in the sub panel box, the ground and neutral come together. Could be a spider web making contact from the neutral terminal to the box or corrosion jumping across neutral bar the box. The easiest way to ensure this is not happening is for your electrician to simply take the two neutral wires of the terminal bar, one is the neutral from the house and the curly neutral from the GFCI and put them together with a wire nut . This will isolate them from ground. The other neutral from the spa is going to a place on the GFCI breaker.

Another possibility is that it is just a bad GFCI and if all above has been done change it out and see if the problem goes away.

All electrical work must be done to local code, adhere to national electrical safety standards and be performed by qualified electricians.

Hot Tub Heater Short Failure

Troubleshoot hot tub heater GFCI tripsWhen looking for a replacement spa heater, be sure to replace it with the same kilowatt rating. 

Although sometimes it is possible to just buy the heater element that goes inside the flow through heater, it is not advisable to change out just the heater element as too much can go wrong with the epoxy seals at the heater terminals and other spacing issues that may cause the heater not to work properly. 

It is most economical and best to replace the entire flow through heater assembly. 

Hot Tub Outpost stocks hundreds of replacement hot tub heaters and heater parts.

See the heater repair tips for more details on taking measurements of a suspected broken heater.

Don't see the part you need? Email us or send us a picture of the one you are replacing and we will send you a link to the best discount heater part online for your particular spa.


How to Install 3 wire hot tub GFCI

 Installation of GFCI should be performed by a licensed electrician.


Voltage Test
The electrician or service tech will take a voltage reading with a multimeter across the 2 terminals of the circuit breaker.  This is the source of the power and for 220-240v spas, the meter should read 240 volts.  The next voltage test will be across the black wire and the green/ground wire. This reading should be 120 volts.  Similarly the voltage between the red wire and green ground wire should be 120 volts.  Now the voltage between the white neutral and the green ground wire at the breaker buss bar should be about 0 volts.  If these readings are correct, the electrician will know the correct power is going to the input of the GFCI.

GFCI Voltage Test
The line input test to the GFCI should be checked to be sure there is no issue in the wiring between the successfully tested circuit breaker in the panel and the GFCI disconnect box.  Again, voltage across the black and red terminals in the GFCI should read 240 volts.  The reading between the black and neutral wire should be 120 volts.  The reading between the red and white neutral wire should be 120 volts.  Finally the voltage between the white neutral and the green ground wire connected to the GFCI box should be about 0 volts.

GFCI Testing - 240 volt spas  
Turn on GFCI breaker:

The voltage measurement between the GFCI load out 1 and 2 (black and red) terminals on the GFCI should be 240 volts.  Black to gfci neutral bar should be 120 volts.  Red to gfci neutral bar should be 120 volts.  Black load out wire and green ground lug should be 120 volts.  Red load out wire to ground lug should also be 120 volts.

Get a hot tub GFCI from Hot Tub Outpost.