GFCI overheating

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KyMama

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Jun 20, 2018
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WINCHESTER
We have a Viking Heritage 2 spa that has been nothing but trouble since we bought it. It constantly trips the 50 amp gfci breaker. According to our infrared thermometer the breaker itself is getting to temperatures of at least 140, it is definitely too hot to touch. When we bought the spa we had our main panel upgraded and the electrician installed a separate breaker in the main panel for the spa as well as the outdoor panel. The electrician used the instructions provided to us by our dealer. Unfortunately that dealer closed about 6 months after our purchase. This has left us without a local dealer and support. Viking sent a tech from another dealer who opened the spa, looked around and decided it wasn't something obvious. He then proceeded to tell us that our wire was too small for the 50 amp breaker. Our wire is 6 gauge which I believe is the correct size wire, at least according to google. He left and that was that. We have talked to Viking so many times and the last time I contacted them they did not call me back. That was several months ago.

The lack of service is why I am here asking for help. We don't use our spa everyday, but I have to check it everyday to make sure that it still has power to ensure that it is not freezing. I know we could drain and winterize but we'd really like to be able to use the spa on milder days. Not to mention that this has been happening for over a year now.

We did have the gfci breaker replaced early into the problem in case it was just a bad breaker. Other than that I don't know what we should do.

Thank you!

ETA: I forgot to mention that it will run for a couple of hours without tripping. Generally I can heat it 3-6 degrees at a time. It takes days to heat it after draining and refilling. Once it reaches the temp it will maintain it but I don't usually leave it set at 103 all the time. lol
 
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KyMama said:
It constantly trips the 50 amp gfci breaker.
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Where is the breaker, in the house panel or near the tub?

How many amps is the tub pulling?

What disconnect is near the tub?

How far is the run from the main panel to the tub?

What is the voltage at the disconnect before the tub is on and what is the voltage when the tub is on (Voltage drop)?

How far from the disconnect to the tub?

What wire size from the disconnect to the tub?

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I'm no expert, but I believe 6 awg is fine for 50 amp service as long as the run is not too long. It's what I ran.

A heated breaker can be caused by a bad connection or overload (normally a breaker is good for no more than 80% of maximum rating continuously).

How long are the wire runs from main to sub and sub panel to tub?

Some tubs require 60 amp service...

One time I replaced a power transistor six times,then sent a parts run cross-country for another replacement which fixed our equipment. Bad batch of parts. Two bad breakers seems unlikely but it could happen.

I'm clueless, but I think I'd start with checks using a clamp meter (Something about your write-up led me believe you're handy). Maybe @RDspaguy will weigh in, he's our "resident expert"...
 
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Mom,

I'm sure I'm going to get schooled by @JamesW but I don't understand how the wire being slightly too small would cause the GFCI breaker to get to hot and fail. Obviously, the breaker is not bad, as it has been replaced.

It seems to me that something on the tub side is the issue. Like an intermittent heater that can short to ground and cause the GFCI to pop. Or an Intermittent Ozone module which can also pop the GFCI.

As a test and only a test, I would replace the GFCI breaker with a standard breaker and see if everything works or not.. If it works, you will know it is a GFCI issue and not a current issue. Which should help you troubleshoot the problem.

Thanks,

Jim R.
 
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The temperature of the breaker indicates it is getting a sustained overload causing thermal trips.

A clamp on amp meter should be put on the circuit to monitor the load during the spa operation.

@RDspaguy may have thoughts.

The basic circuit breaker used in both residential and light commercial applications is called the T-M or Thermal Magnetic Circuit Breaker. Another term that is sometimes used is the MCCB, or MoldedCase Circuit Breaker.

The T-M circuit breaker has two independent trip mechanisms: thermal and magnetic. The former reacts to overloads and causes the breaker to trip, while the latter responds to short circuit fault currents.

The first (and most common) misconception is that a breaker trips when its nameplate rating is exceeded.

A 20 amp breaker must trip at a sustained current of 27 amperes (135 percent) at less than one hour, and at 40 amperes (200 percent of wire rating) in less than 120 seconds—far different from what the cited text implies. These two trip points (135 percent and 200 percent) are defined in NEMA Standard AB-1, MCCBs and Molded Case Switches.

The thermal portion of the circuit breaker works by use of a bi-metallic strip which causes a spring-loaded latch to release and trip the breaker. The deflection of the bi-metallic strip depends on the temperature, thus the breaker has a trip temperature and it is the heat generated within the breaker that causes the temperature to rise, the faster the heat rise, the faster the breaker reaches temperature and trips. Heat is directly proportional to the power (watts), which is proportional to the square of the current (P=I2 x R)

https://goodsonengineering.com/wp-content/uploads/2017/08/CircuitBreakerMyths_web.pdf
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Breaker tripping after adding Aquarite SWG

Hello all! This place has been a great resource in the past, and I'm hoping for some more advice regarding electrical wiring. I'm posting mostly to get a second opinion and make sure my thinking is correct and that I'm not missing any obvious options or things to check. Last summer I had no...
www.troublefreepool.com www.troublefreepool.com
 
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JamesW said:
Where is the breaker, in the house panel or near the tub?

How many amps is the tub pulling?

What disconnect is near the tub?

How far is the run from the main panel to the tub?

What is the voltage at the disconnect before the tub is on and what is the voltage when the tub is on (Voltage drop)?

How far from the disconnect to the tub?

What wire size from the disconnect to the tub?
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The breaker that is tripping is near the hot tub.

I'm not sure how many amps it's pulling because I don't know how to measure that. I'm assuming I need a clamp meter and I don't have one of those yet. I have no problem buying new tools if that's what I need.

The disconnect is the spa panel with the gfci.

The run from the main panel to the spa panel is approximately 40 foot.

Once again I don't know or how to measure.

The pig tail is about 10 foot long because it goes around the back of the tub from the panel.

Not sure on the wire size.

Our dealer was very specific about the electrical connection. They had a list of electricians to use and insisted that they would be able to inspect and hook up the tub themselves. They commented that a lot of electricians didn't know how to hook up the tub correctly. He did inspect everything and was happy with the electric when installing the tub.
 

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So it seems that I need to get a clamp meter and test it myself. I'm handy enough but electrical makes me nervous so I don't usually do anything without specific instructions.

I'm sure on the wire size. It is ran through the unfinished part of my basement so it's easy enough to see and read. It says Romex SIMpull 6 AWG.

Why would the dealer have us install a 50 amp if it needs a 60 amp? Does that mean we are going to have to pay to have it ran again? I think we can agree that's ridiculous to follow directions to only have to redo it. The tech they sent from the other dealer looked at the panel and didn't say anything about it being too small. On this subject, would just calling for heat overload a 50 amp? I realize there are other things drawing power, not just the heater but this is when it trips. Once it reaches temp we can use it as normal with both jets and through heat cycles and it's fine.

Thanks for all the help. It will probably be Sunday before I can get the clamp meter and run a few tests. I'll be sure to come back and post the results, probably with more questions. Thanks again, y'all have been more helpful in a few hours than Viking and the dealers in two years.
 
I don't understand the significance of Allan's @ajw22 2nd reference, but I think all the cards are on the table so to speak.

It seems more information is needed.

From what is known I'd be willing to stipulate for now that 6 awg wire is adequate for the distances. I also feel a 60 amp breaker is mandatory and your installer responsible for an immediate upgrade.

That your breaker is underrated, I'd suggest the electrician to replace it should verify current draw is within spec while onsite.

That said, sadly, you want it now with as little hassle as possible the old adage may apply, "if you want it done right do it yourself." If you do, you risk your warranty...

Your call @KyMama!

If proceeding, you almost certainly need to upgrade to 60 amp gfci. Perhaps it's best to invest in a torque screwdriver and proper bit, and you would be better off purchasing a clamp meter and verifying current draw, and that your pigtail is 6 awg (8 awg might work but i think it's a really bad idea).

Electrical work is inherently deadly, just saying ... 100% confidence required!!!
 
Methuselah said:
I don't understand the significance of Allan's @ajw22 2nd reference, but I think all the cards are on the table so to speak.

It seems more information is needed.

From what is known I'd be willing to stipulate for now that 6 awg wire is adequate for the distances. I also feel a 60 amp breaker is mandatory and your installer responsible for an immediate upgrade.

That your breaker is underrated, I'd suggest the electrician to replace it should verify current draw is within spec while onsite.

That said, sadly, you want it now with as little hassle as possible the old adage may apply, "if you want it done right do it yourself." If you do, you risk your warranty...

Your call @KyMama!

If proceeding, you almost certainly need to upgrade to 60 amp gfci. Perhaps it's best to invest in a torque screwdriver and proper bit, and you would be better off purchasing a clamp meter and verifying current draw, and that your pigtail is 6 awg (8 awg might work but i think it's a really bad idea).

Electrical work is inherently deadly, just saying ... 100% confidence required!!!
Click to expand...
I don't necessarily want it with as little hassle as possible, I do want it without spending too much money on fixes that don't work. And this has been going on since we bought the tub 2 years ago so getting anything done "now" has long passed. What I really want is a relaxing hot tub, that's really all I ever wanted. Right now, just thinking about it stresses me out.

The hubby is gonna stop on his way home from work and grab me a clamp meter because I never turn down another tool. This weekend I will use it and get some readings that hopefully will help narrow down the problem. If it means I need a 60 amp then that's what we'll do and by we I mean my electrician. I'm willing to do small electrical work like switching plugs and installing lights but I draw the line at messing with the breakers because I don't have the knowledge and don't want to die. I have a healthy fear of electricity.

Would the 6 awg from the main panel to the spa panel need to be replaced with 4 awg if upgrading to a 60 amp? How do I check the pigtail? I know there are individual wires running through there because I watched the electrician but I don't know how to determine the wire size. I ask these questions, not because I plan to do it myself but to know what to ask for if needed.

Thanks!
 
NEC requires CBs to be loaded at no more than 80% of rated capacity.

The 50 amp breaker should not have more than 40 amp load.

A 60 amp breaker can take a 48 amp load.

I would check the amps before replacing the wiring and CB. There are lots of YouTube videos on how to use a clamp on ammeter.
 
Your 6 AWG copper wire may be adequate for a 60 amp circuit. It depends on the type of wire used and the length of the run. See…

Wire Size Chart

Wire Size Chart and current limits for wire gauges
wiresizecalculator.net
 
The specified breaker is 60 amps, so that it what needs to be installed.

Any time current is flowing, heat is being generated as it goes through the wires and the breaker.

As long as the amount of current is lower than the breaker ampacity rating and/or wire ampacity rating, the temperature of the wire and/or breaker should not get too hot.

Ampacities need to be derated for ambient temperatures over 86 degrees, but for most applications, this is not a significant issue.

The breaker might be getting hot from too much current causing the breaker to overheat or it might be from the wires overheating and the heat transferring to the breaker.

What temperatures do you get for the wires?

Do the wires feel hot or just the breaker?

The first thing to check is the voltage at the tub line in terminals with the breaker on and the heater off or the breaker line terminals with the breaker off and then the voltage and current when the tub is on and heating.

The voltage before load minus the voltage after load is the voltage drop.

The voltage drop should not be more than 7 volts and the voltage when under load should be at least 223 volt.
 
KyMama said:
I don't necessarily want it with as little hassle as possible, I do want it without spending too much money on fixes that don't work. And this has been going on since we bought the tub 2 years ago so getting anything done "now" has long passed. What I really want is a relaxing hot tub, that's really all I ever wanted. Right now, just thinking about it stresses me out.

The hubby is gonna stop on his way home from work and grab me a clamp meter because I never turn down another tool. This weekend I will use it and get some readings that hopefully will help narrow down the problem. If it means I need a 60 amp then that's what we'll do and by we I mean my electrician. I'm willing to do small electrical work like switching plugs and installing lights but I draw the line at messing with the breakers because I don't have the knowledge and don't want to die. I have a healthy fear of electricity.

Would the 6 awg from the main panel to the spa panel need to be replaced with 4 awg if upgrading to a 60 amp? How do I check the pigtail? I know there are individual wires running through there because I watched the electrician but I don't know how to determine the wire size. I ask these questions, not because I plan to do it myself but to know what to ask for if needed.

Thanks!
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6 awg for your 40 ft. run is fine. On the pigtail run, gage will be in writing on the wires, or compare to other wires, but #1 suspect is 50 Amp breaker should be 60 Amp rated per @JamesW in post #4.

Yes, the breaker is expensive, but I think if you call the manufacturer and explain their dealer's electrician installed a 50 Amp breaker they will confirm it needs to be 60. Using a clamp meter provides a confidence check that there are no other issues. If it were my tub I'd replace that breaker.

I see @JamesW has posted (I type slow...), know feeling wires vs. breaker ignores the possibility heat is being generated by loosened connections at the breaker screws. I didn't harp on that because I figured that's irrelevant if you changed the breaker (which identifies and solves that issue). Just an fyi.

BTW, if your breaker box doesn't accommodate a 60a replacement and you end up replacing the box too, you might recover some cost selling the old one on fb marketplace?
 
Breakers have a thermal trip mechanism and a magnetic trip mechanism.

GFCI breakers have a ground fault trip mechanism and Arc fault breakers detect any type of arcing.

So, the tripping might be thermal overload, ground fault or possibly arc-fault if the breaker is arc-fault.

Can you show a picture of the breaker in the main house panel and the breaker near the tub?

The magnetic trip mechanism is for a direct short with very high current (about 10 X the breaker rating).

The thermal trip mechanism is for sustained overload conditions.

The two specified trip points are 135% and 200% of the breaker rating.

For a 50 amp breaker tripping on thermal overload suggests a load of more than (50 x 1.35) = 67.5 amps.

A 50 amp breaker has to trip in less than 6 minutes with a 200% load (100 amps on a 50 amp breaker).

A 20 amp breaker must trip at a sustained current of 27 amperes (135 percent) at less than one hour, and at 40 amperes (200 percent of wire rating) in less than 120 seconds—far different from what the cited text implies.

These two trip points (135 percent and 200 percent) are defined in NEMA Standard AB-1, MCCBs and Molded Case Switches[2].

TABLE 1 lists the 200 percent allowable trip times for different size (amperage) circuit breakers. MCCBs have characteristic ‘curves’ published by their respective manufacturers.
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Can you provide a better description of the entire wiring path?

What breaker size in the main house panel is feeding the tub?

How hot is that breaker getting?

Is there a second GFCI breaker near the tub?

What is the wire size from the breaker near the tub to the spa pack?

Are there 4 wires from the GFCI breaker near the tub to the tub?

Can the tub be wired for only 230 or can it be wired for 120 volts?

Check the amperage on each hot leg and on the neutral.

Can you show the breaker wiring and the wiring connections at the tub?
 
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KyMama said:
It says Romex SIMpull 6 AWG.
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Southwire Romex® Brand SIMpull ® Type NM-B cable (nonmetallic-sheathed cable) may be used for both exposed and concealed work in normally dry locations at temperatures not to exceed 90°C (with ampacity limited to that for 60°C conductors).

NM-B cable is primarily used in residential wiring as branch circuits for outlets, switches, lighting, and other loads.

NM-B cable may be run in air voids of masonry block or tile walls where such walls are not wet or damp locations. Available in copper only.

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The tub manual specifies a 60 amp breaker, which means that the wire also has to be rated to at least 60 amps.

The Romex NM-B 6 AWG is only rated to 55 amps, which means that it is too small.

The correct NM-B Romex would be #4 AWG.

In my opinion, the wire and breaker need to be redone to meet the specifications.

If the tub is pulling more than 48 amps on either hot leg or the neutral, then there is a problem with the spa pack.

The problem might be a GFCI trip and you should test for continuity to ground to rule out ground faults.

If the current is lower than 48 amps, then the trip is likely to be GFCI.

The excessive temperature of the breaker indicates a possible thermal overload due to excessive current over 50 amps.

Note: All tests should only be done by a qualified professional.

Only do things that you are 100% sure that you can do safely and correctly.
 
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