Hot Tub Tripping GFI Problem

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  #1  
Old 08-29-05, 09:22 PM
Pop N Wood
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Hot Tub Tripping GFI Problem

Hey, nice site. Did a search but did not find an answer to what may be an unusual problem.

Just finished installing a “free” hot tub (the tub was free, installation ended up costing me $3k). Got the tub to work with one exception: the GFI breaker pops instantly whenever the air blower is turned on.

Wiring is as follows. I wired the tub to an external subpanel with a 50A, 230V GFI breaker. This goes to a standard 50 A breaker in the main house panel. 4 conductor wire is used from the house, to the subpanel breaker and into the spa controller. The ground and neutral wires are not interconnected at the subpanel. The house breaker and spa subpanel are both new.

All of the spa 230 volt features work fine (a circ pump, two jet pumps, ozonator and heater). But turning on the 110V air blower causes the GFI breaker to trip instantly. Disconnecting the air blower from the spa controller allows the circuit to be activated without tripping the breaker. Can hear the relays cycle, see the indicator light come on and measure 110V across the blower contacts. I am seeing zero volts from the neutral to ground.

Resistance checks on the blower motor reveal 3.2 ohms across the power windings, and an infinite reading from neutral to ground, hot to ground and hot/neutral to the spa chassis. I pulled the blower motor into my shop and powered it from a 110V GFI receptacle. The blower ran fine without tripping the 110V GFI receptacle. The motor looks to be in perfect condition.

Took the blower back out to the spa, hooked it to the controller and promptly tripped the 220V GFI breaker when the blower gets turned on. Should point out that the GFI trips regardless of what other loads are on or off.

I am not sure where to go from here or what else I can test. May be just coincidence, but why is just the 110V load tripping the GFI breaker? Anyone know if connecting a single 110V load to one side of a 220V GFI breaker will cause it to trip?

Thanks in advance for any insight or help.
 
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  #2  
Old 08-29-05, 11:20 PM
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Just to verify is your wiring as shown in this diagram? Look closely at how the neutral curly pigtail of the gfci is wired and the neutral leaving to the spa. Pigtail to the neutral bar (with the line neutral) and load neutral connected to the gfci.

http://www.emeraldspa.com/wire.htm
 

Last edited by Roger; 08-30-05 at 11:03 AM.
  #3  
Old 08-30-05, 04:55 AM
Pop N Wood
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You know I looked the direction for the Cutler Hammer over very carefully several times before I even started this project. I have done a lot of wiring but this is my first GFI breaker. I thought I had things hooked up exactly as shown in the manual for my box

http://www.eatonelectrical.com/unsec...M00301063E.PDF

BUT let me double check the neutral connections. I think I might have wired the load to the neutral bar. If the neutral current with the unbalanced load is not going through the breaker, than what I am seeing would make sense.

I'll get back to you. Thanks.
 
  #4  
Old 08-30-05, 11:06 AM
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Well yours is the same just that my diagram link shows it in color

Those cutler hammer directions are very good directions so dont get your hopes up too much.

I hope it will be as simple as that but lets see what you get when you check.
 
  #5  
Old 08-30-05, 04:53 PM
Pop N Wood
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Yeah, had the tub neutral hooked up to the neutral bar. Put it where it belongs and all is well.

Thanks for your help. If you hadn't forced me to look at that diagram more closely I would still be hearing it from the wife.
 
  #6  
Old 08-30-05, 05:30 PM
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Im glad all is well and we didnt have to go searching for something obscure inside the spa.
 
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