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#54725 - 08/06/05 02:54 AM 250 volts gfci  
estman7  Offline
Junior Member
Joined: Jul 2005
Posts: 1
Hello everyone,
I ran into this stuation a few days ago. I am installing the motors for a jacuzzy which come with three wires, 2 hots and 1 ground. when I tried to connect a gfci cb it kept tripping. Since I dont a neutral for the load, I am trying to play with the ground to get my zero reference voltage. I am not sure if this will work though. any input from the zen masters will be appreciated.

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#54726 - 08/06/05 10:10 AM Re: 250 volts gfci  
pauluk  Offline
Joined: Aug 2001
Posts: 7,520
Norfolk, England

play with the ground to get my zero reference voltage.

Not sure what you mean by this? [Linked Image]

The grounding wire needs to be securely connected to the ground bus at the distribution panel -- There's no way it should go anywhere else.

#54727 - 08/06/05 12:38 PM Re: 250 volts gfci  
e57  Offline
Joined: May 2003
Posts: 2,876
It a Ground Fault Circuit Intertupter, do you think there may be a Ground Fault?

It's possible....

Mark Heller
"Well - I oughta....." -Jackie Gleason

#54728 - 08/06/05 12:51 PM Re: 250 volts gfci  
Larry Fine  Offline
Joined: Feb 2005
Posts: 693
Richmond, VA
Estman, don't forget that you must connect the GFCI breaker's white to the neutral bus, even if the load has no neutral, and the EGC must be tied directly to the neutral (or separate ground bus if there is one) just as with any circuit.

Larry Fine
Fine Electric Co.

#54729 - 08/06/05 02:48 PM Re: 250 volts gfci  
SolarPowered  Offline
Joined: Jul 2004
Posts: 625
Palo Alto, CA, USA
As Larry said, the GFCI's white neutral connects to the neutral bus. The neutral terminal on the GFCI has no connection at all--there's no neutral on the circuit, so there isn't supposed to be any current flow through that terminal.

Also, GFCIs don't work with "reference voltages"s; they work by summing all the current passing in and out of the circuit, which should sum to zero. If it doesn't sum to zero, that indicates that there's a ground fault somewhere, and the GFCI trips. So any connection you make to the neutral terminal will generate an unbalanced condition, tripping the GFCI.

[This message has been edited by SolarPowered (edited 08-06-2005).]

#54730 - 08/06/05 03:10 PM Re: 250 volts gfci  
renosteinke  Offline
Cat Servant
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
I had a similar problem...which the tub maker was just certain was caused by my mis-connecting the GFI breaker. So I began disconnecting various parts of the tub's systems- until I could say "it works fine until the stereo is connected."
Only then did they send some one out to replace the faulty item.

I know it's hard to believe, but sometimes GFCI's trip and fuses blow- because they're supposed to!

#54731 - 08/07/05 11:37 AM Re: 250 volts gfci  
livetoride  Offline
Joined: Jan 2005
Posts: 109
san diego ca usa
Had a simular problem and it turned out to be the ozone filter unpluged it and all was fine. Rod

#54732 - 08/07/05 02:45 PM Re: 250 volts gfci  
Electric Eagle  Offline
Joined: Apr 2002
Posts: 914
Alpharetta, GA
Another posibility is the breaker is bad. I've seen it several times.

#54733 - 08/07/05 09:35 PM Re: 250 volts gfci  
Paulusgnome  Offline
Joined: Jun 2004
Posts: 56
Christchurch, New Zealand
If your load has two 'hot' wires and no neutral, then one would assume that all current is normally carried by the two 'hot' wires alone, yes?
Therefore, what is needed is to use a 2-pole RCD (GFCI) and run each 'hot' through one pole of the RCD.

The RCD works on by tripping on a current imbalance between the two conductors - if the current in one 'hot' is not the same as in the other 'hot' then the difference must be going to earth.

FWIW, this approach also works with 3-pole RCDs in a 3-phase circuit without neutral.

Mark aka Paulus

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