Strange hot tub question on gfci

[69charged]

Hello all. I am having a problem with my hot tub I installed about 3 months ago. It is a 220 volt model. What this means is there in no neutral going from my gfci breaker to the tub.

Anyway, I'll start from the beginning. I have the main breaker panel in my house with 200 amp service. In there, is a 60 amp breaker(stablok, junk!!). From this breaker I had to run it to a small sub panel so I could run a heater for my garage. In the sub panel is another 60 amp breaker to a gfci breaker outside by the tub. Also in the sub panel is a 30 amp breaker to feed my heater in the garage. The main panel to sub panel is #6 3 wire, about 3ft long. Sub panel to gfci panel is same wire, about 15ft long. Gfci to tub is 2 wire, about 13ft long. Main to sub, then sub to gfci are both grounded and have the neutral. Not to the same bar either. From the gfci to the tub is no neutral as the tub manufacturer doesn't call for it.

So, I was using the tub for about 2 months, with no problems. Then as its getting colder, I needed heat in my garage, so I flipped on the heater. All was good for roughly 2 weeks. Next thing I know I go outside to get in the tub, and its off. The gfci had tripped. So I reset it, and away I went. It didn't trip off for another week. Ever since then, it's randomly tripping. Like maybe it trips in the middle of the night, then not for 2 days. Then it will go a week without tripping. I am having a hard time finding the problem because its so random.

Is it possible for the gfci to sense a fault before it? Like between the gfci panel back to the sub panel then on to the main?
Also, is there a relation to having my heater kick on or off causing a spike that the gfci sees and trips? Then why not all the time? It would be the easiest to just turn the heater off, but I need it on and I can't let my tub go too long with out it freezing.

Sorry the post is so long, but I really hope to get this cleared up before winter really sets in.
Thanks
Clarence

 

[Charles (in GA)]

GFCI cannot "see" or trip due to anything before it in the circuit. Could be the hot tub heater circuit is tripping it due to its thermostat cycling/arcing. Sorry, no real good ideas however.

Charles

 

[69charged]

I also intend on meggering the wiring to see if there is a leak somewhere, I just have not gotten to it yet. I thought maybe I found the problem, as I found one of the line side wire terminals a little loose. Nope, still did it the next day. Also, last night I woke up to let my dog out at about 3 in the morning, and I heard the tubs second pump kick in for about 2 seconds, then quit. When I checked the tub this morning, it had tripped.
Clarence

 

[69charged]

Thanks Charles. If there were a minute difference in voltage on either the line or neutral, because of my heater kicking in, could the gfci not pick that up? Seeing as it only takes .05 mA to trip it?

 

[Charles (in GA)]

Its possible the garage heater, and the hot tub heater/pump? when both are operating at the same time, are causing some sort of sympathy harmonics or something that trips the GFCI. GFCI's look at current flow (milliamps) thru a coil in them.

Charles

 

[69charged]

Yeah, understood. I tried running everything together at once. Heater, and all tub parts. Lights, pumps, ozonator, and calling for heat. No problem.

 

[69charged]

Also did an amp draw just to rule that out. Tub runs 45.5 on one leg, 45.0 on the other. Any 120 is coming off one leg so that accounts for the difference there.

 

[wyliesdiesels]

Also did an amp draw just to rule that out. Tub runs 45.5 on one leg, 45.0 on the other. Any 120 is coming off one leg so that accounts for the difference there.

Well theres your problem right there. Why is there a difference between the legs.? There shouldnt be. If theres no neutral, then the current traveling on each leg should be the same. Since u have a difference of half an amp(GFCIs trip on as little 4-6ma), the GFCI will trip. Do u have a leak to ground somewhere? Where is that .5a going? Is it possible u have a 120v device in the tub that is using the EGC/ground as a neutral return path? U mentioned it is getting colder. U might have condensation getting into something that is causing a short to ground.

And what do u mean by " Any 120 is coming off one leg so that accounts for the difference there." ?

 

[69charged]

Some of the control panel is 120. Looking at the wiring diagram, I am ASSUMING that the 120 portion is being pulled from one leg to account for the difference. I can see that it is.

Ok, wife just checked the tub this morning. It's tripped again, and I shut the heater off in my garage last night! We are getting closer!

Clarence

 

[69charged]

Ok, just reset it this morning, and within 2 mins, it blew again. Watched it and it blows after pump 2 has run for about 5 seconds. If it was a ground fault, it would blow almost instantly. I'm thinking weak breaker as it takes a few seconds to blow. Unless of course the motor is drawing too much current, which would cause it to go. I will dig further again with the clip on and see what I see!
Clarence

 

[wyliesdiesels]

Some of the control panel is 120. Looking at the wiring diagram, I am ASSUMING that the 120 portion is being pulled from one leg to account for the difference. I can see that it is.

Ok, wife just checked the tub this morning. It's tripped again, and I shut the heater off in my garage last night! We are getting closer!

Clarence

If some of your control panel is 120v, how is it connected since theres no neutral feeding it? Does it have its own step down transformer? Are u sure that this tub doesnt need a neutral? Pulling electricity from one leg would still need a neutral to connect the other end of the circuit to, so that doesnt account for the difference in readings!! Is it possible your tub is returning some current on the ground wire?

Do u know how a GFCI works? It senses and compares the current flowing on each hot leg. If theres an imbalance, it will trip. U already said there IS an imbalance. The GFCI breaker will also trip for the usual common reasons such as overcurrent and short circuits. If it trips when a particular pump comes on, them that motor may have a wiring issue.

 

[69charged]

Yes there is a step down transformer. I metered the current draw on full load and those were the numbers I got. I fully understand how gfci's work, so why doesn't it trip when everything is on then? There is .5 amp difference between the legs and it doesn't trip. They are not watching the difference of the load leads. It's watching the difference of a lead to neutral which is its reference. If there is too much difference for whatever reason, the programmed control logic sends a signal to the coil inside to trip.
I do however, understand what you mean to say there is no neutral return path from the tub to the neutral bar in the gfci panel.

Clarence

 

[69charged]

http://www.spacare.com/howtowireagfcibreaker.aspx

Here is my set up. I even had to double check with the tub manufacturer to ask that the neutral was not required, which I felt was strange.
It's the second diagram down.

 

[rockwithjason]

you have a ground fault somewhere in the hot tub circuit. the path can be intermittent in nature. you will have to isolate the tub's components and wiring one by one until you find the fault. be very careful with the megger as you can fry control boards in a heart beat.

 

[justsam]

Yes there is a step down transformer. I metered the current draw on full load and those were the numbers I got. I fully understand how gfci's work, so why doesn't it trip when everything is on then? There is .5 amp difference between the legs and it doesn't trip. They are not watching the difference of the load leads. It's watching the difference of a lead to neutral which is its reference. If there is too much difference for whatever reason, the programmed control logic sends a signal to the coil inside to trip.
I do however, understand what you mean to say there is no neutral return path from the tub to the neutral bar in the gfci panel.

Clarence

I believe you will find that the trip detection for the 240v breaker is via current inbalance in L1and L2, the hot load leads, neutral is not in the equation as in a 120V device.

Check for some ground leakage current by inserting an AC ammeter in series with the ground lead. Make sure it is well connected since you will not have a ground if this is disconnected or the ammeter goes open for any reason. Of course if you have a sensitive enough clamp on device, better to measure using it.

How accurate is you clamp on ammeter? Does it consistently show the 0.5 Amp difference? Is it a Fluke, Dranetz, etc.?

Can you see the circuitry of the step down transformer? Is it a simple two wire primary and secondary, or is there a center tap?

 

[landyacht]

Just speculation, but it trips after 5 seconds to 2 minutes of pump 2 running. I suspect your issue is there. Perhaps seepage due to moisture when it's spinning. Either way you should be able to disconnect pump 2 at the controller (or manually if you have to). It sounds like this is happening more and more frequently, so disconnect pump 2 for a day or 2 and see if the problem disappears. If so at least you have an area to start looking. If not then try pump one, then manually disconnect the control relays (they can spark causing an issue).
Don't get too frustrated - the thing people always seam to forget when they're getting upset with a tripping GFI is it is often saving your life when it trips.

 

[madosta]

Weirdest thing... my Grandmother bought a new house recently with a Balboa hottub, that was half full when she closed. So I turned it off at the outside breaker until she could figure out what to do with it. Well someone tried to get it started, filled it with water, chlorine, cleaned it, etc. and it kept tripping the breaker randomly.

Turned out to be a vapor lock or air bubble in one of the lines and the pump or heater was causing the trip. All the lines bled and the thing has been running fine ever since.

I would look at your hottub before anything else.

 

[RickP]

Nuisance tripping gfci breakers is pretty common for hot tubs. You might have a perfectly good hot tub and a marginal breaker. If you Google it, there's lots of troubleshooting info available.

 

[wyliesdiesels]

Yes there is a step down transformer. I metered the current draw on full load and those were the numbers I got. I fully understand how gfci's work, so why doesn't it trip when everything is on then? There is .5 amp difference between the legs and it doesn't trip. They are not watching the difference of the load leads. It's watching the difference of a lead to neutral which is its reference. If there is too much difference for whatever reason, the programmed control logic sends a signal to the coil inside to trip.
I do however, understand what you mean to say there is no neutral return path from the tub to the neutral bar in the gfci panel.

Clarence

Does the GFCI breaker have a neutral pig tail? IF it does, it not only measures the current of L1 and L2 but also the current returning on the neutral. If your tub and breaker doesnt have a neutral then the breaker most certainly wouldnt "watch the difference of a lead to neutral" because it doesnt have a neutral and is a 240v only breaker.

 

[69charged]

Yes ther is a pigtail going from the breaker to the neutral bar.
Justsam, I am going to pull the cover off the tub again today to do some more looking around, but I am certain that it has something to do with pump 2 kicking on by itself. I am told by the store where we bought it that pump 2 kicks in a few times a day to clear out the jets, and its then that it trips. I can manually turn on pump 2 and run it all day with no problems. So I am thinking it has something to do with a timer, or some other relay that is programmed to tell pump 2 to turn on.
Will let you know what I or the store guys find.
Thanks guys
Clarence

 

[Gmdodt]

Did you find a fix? I don't have the separate heater set up but I seem to have the identical issue and been trying to troubleshoot for 6 months.