GFI trip hot tub

[jetlag]

I have customer with a hot tub that has the factory installed GFCI in the tub . It is not one that serves as as an overcurrent breaker. It reads the two hot lines like a clamp on amprobe would. If they dont equal it trips a small breaker that breakes the primary to a 240 volt relay which stops the current.. Ok the tub will run a while and the breaker trips . since it doesnt break for an overload and the breaker in the main panel doesnt trip i am assuming there is a small ground fault leak some where. problem is how do i locate it . it has pumps , lights , hearters ect . I plan to check amp draw on every thing but not expecting to find a problem there since that gfci is more like a gfci receptacle , it reads the fault but not over current

 

[jetlag]

gfci in hot tub

gfci in hot tub

Oh i forgot to say it could be a bad gfci itself but i dont know how to check. I dont believe an amprobe on each line will be accurate enough to look for a difference , especially since it runs a while before it trips

 

[480sparky]

I never seen a GFCI-only breaker-type device. All I've ever seen are GFCI breakers.

 

[jetlag]

same here

same here

I never seen a GFCI-only breaker-type device. All I've ever seen are GFCI breakers.

well i guess it could read overcurrent also and trip. The two hot wires dont connect to the breaker , the simply pass thru two openings an on to a relay which the GFCI breaker controls. good point maybe it is reading an overload

 

[Dennis Alwon]

Jetlag, explain more. Is this a Hot Tub and not a hydromassage tub? I assume you haven't checked the amps, correct? Explain this breaker please-- Also if the tub has a heater it may be tripping the GFCI when the heater engages. THis is a common area of fault for tubs.

I don't work on tubs so I leave that to the manufacturer but as I said before the heater coil may be your problem.

 

[LarryFine]

If you really want to troubleshoot the tub, try isolating each load (heater, main pump, blower, lighting, etc.) until you find one that lets the GFCI remain engaged.

My experience has also been that most often, the heater element develops internal leakage to the water and/or the housing.

Added: And, you're right, GFCI's do measure current just like clamp-on ammeters do.

 

[hurk27]

I have had worked on a few of these type hot tubs, and they are UL listed to have its own GFCI so no up stream GFCI device is needed just the breaker serving the load, in the ones I have worked on, they will have a faceless GFCI with a donut on the back where the feeders run through, this faceless has contacts on it to control a 2 or 3 pole contactor which will shut off the power to the tub if a leakage is detected. I agree that the most common ground fault found in a hot tub is the heater unit, this is because a home owner will shut off the power and clean the tub, then start filling it, and turn on the power befor the tub has enough water in it, most tubs default to heat when there is a power failure, so the heater comes back on with no water, most have flow detection now, so its not as big a problem as it used to be, but I still get calls on many older ones.

But un hooking loads one at a time will find the problem load and is about the best way to find it.

The last one I went on was the air pump. home owner said he could live without it, so I just un plugged it, and the rest worked fine.

 

[busman]

Buy one of these. They are worth the money.

http://us.fluke.com/fluke/usen/Electrical-Test-Tools/Clamp-Meters/Fluke-360.htm?PID=56072

Mark

 

[hillbilly1]

My money is on the heater, there is a delay before it is energized due to flow acknowledgement switches and such, I have seen them use shunt trip type breakers instead of GFI type. The ct is remote from the breaker, they use this type on some portable generators too.

 

[Jim W in Tampa]

As been said the heaters often leak. Start by measuring amps , if that proves to be about normal i would then remove both wires from heater. Same for blower and lights. Be careful not to remove pump as no flow will burn up a heater. Most of the new ones have flow protection by pressure switch.
You did not give us an amount of time it works before triping.
Is always possable it is the gfi itself.

 

[macmikeman]

I have had about a half dozen times the same problems and it turned out to be the heaters. I now put a warrenty disclaimer on hot tub tripping issues into each hot tub wiring proposal.

 

[joebell]

I have had about a half dozen times the same problems and it turned out to be the heaters. I now put a warrenty disclaimer on hot tub tripping issues into each hot tub wiring proposal.

Just curious, how quick after the oringal install did the heaters let go and cause the GFCI to trip?

 

[jetlag]

Thanks Joebell

Thanks Joebell

Just curious, how quick after the oringal install did the heaters let go and cause the GFCI to trip?

This was a 2009 demonstration model and the owner installed it 3 months ago . I forgot to ask him when it started to trip. I am just getting around to checking it yesterday . The amp draw is normal on everything . Im going back again and disconnect things untill it stops triping , it runs about 3 or 4 min before it trips. Reading the posts I am starting to suspect the heater element is leaking current. Strange thing on that GFCI all the leads hot and neutral go thru the same doenut hole. I dont see how it reads the current that way .

 

[Jim W in Tampa]

The PH of the water could cause problems fast. Might warn them to keep eye on it. Very small amount of water and can change in a few hours. I dump my water after every week after the party. Tub is over 2 years old and no problems. Have had gfi (external) trip a few times for unknown reasons but it is months in between.

 

[macmikeman]

Just curious, how quick after the oringal install did the heaters let go and cause the GFCI to trip?

Mostly fairly quick. I might add most of these came from the same company. They know my name at support now.....

 

[LarryFine]

Strange thing on that GFCI all the leads hot and neutral go thru the same doenut hole. I dont see how it reads the current that way .

You're subconsciously getting the point. That's how GFCI's work. As long as all current is flowing through the ring, the device knows nobody is getting a shock.

Any current that is leaving the circuit past the ring is current presumed to be traveling through a person on its way back to the neutral through the electrodes.

 

[LarryFine]

They know my name at support now.....

"Him!"

 

[brother]

Buy one of these. They are worth the money.

http://us.fluke.com/fluke/usen/Electrical-Test-Tools/Clamp-Meters/Fluke-360.htm?PID=56072

Mark

Would not an old time megger work the same?

 

[busman]

Would not an old time megger work the same?

I have both, but they have different uses.

The megger is fine for things without electronics. Motors, transformers, etc. and things that you don't want to energize at high current such as feeders.

The leakage current clamp is great because it works on a normally energized piece of equipment. It's fairly safe because it's basically non-contact (just like any other current clamp). And, it tells you just how much current is leaking (in microamps). You wouldn't think it could be that accurate, but trust me, it is. I've found more uses for this than I ever thought I would.

Mark

 

[jetlag]

thanks larry

thanks larry

You're subconsciously getting the point. That's how GFCI's work. As long as all current is flowing through the ring, the device knows nobody is getting a shock.

Any current that is leaving the circuit past the ring is current presumed to be traveling through a person on its way back to the neutral through the electrodes.

i guess ive been confused how gfci works , i thought it measured the conductors seperately they must be equal in the hot lines or the difference will be in the neutral. according to what I see if you put a clamp on meter on all the hot and neutral comming in together it should cancell the current and read zero unless there is a leak thats not returning. I still dont understand what all the other wires are doing in the doenut hole , There are a lot more wires than the 3 lead in conductors.