New 240V whirlpool tub and GFI

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  #1  
Old 07-29-06, 08:12 PM
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New 240V whirlpool tub and GFI

Hi all,

I just installed a new whirlpool tub using a 2 pole 20A GFI breaker and 12/3 wire.
As soon as I flipped the GFI on, the GFI tripped.
At first I thought I might have a short someplace. After checking the wiring and finding no problems with the cable, I disconnected all the wires from the GFI breaker, and with no wires connected it doesnt trip.
As soon as I connect the neutral (no hots connected yet) the GFI trips ( the pigtail from GFI is on the GND bar in panel)
Can anyone explain this?
This is how it is wired:

whirlpool:---------Wire: ----------------GFI breaker:
blue--------------black ----------------Hot #1 screw
Black-------------Red ------------------Hot #2 screw
Green-------------White ----------------Neutral screw
GND screw---------bare ----------------GND bar in panel
and the pigtail from the GFI goes to the GND bar in panel.

Is the wiring correct
I am puzzled.
I think I read somewhere in one of the tubs booklets to use 2 wires with gnd.
Do I even need the netural wire, if the tub is 240V?

Thanks in advance.
Mike
 
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  #2  
Old 07-30-06, 05:23 AM
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As strange as it sounds, do NOT connect the white to ANYTHING. Especially NOT A GREEN OR GROUND!

In fact you wasted some money buying the 12/3. 12/2 would have been sufficient. You just have to mark the white with a permanent marker. But this is hindsight.

Tightly cap off the white at both ends with a wire nut.
Leave all else as is.
The breaker DOES NOT need a load neutral connection to function. In fact a 240v motor has NO neutral connection. The breaker neutral tail must still be connected to the neutral bar though.
 
  #3  
Old 07-30-06, 05:47 AM
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Speedy,
Thanks for your quick reply.
At the time I ran the wire I wasnt sue if the tub needed 12/2 or 12/3 since I didnt have the tub yet. I figured better run 12/3 to be safe.

I still dont understand why connecting the -neutral only- would trip it.

As you suggested I will just cap off the Neutral on both ends.

Thanks,
Mike
 
  #4  
Old 07-30-06, 06:25 AM
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The green wire at the tub is for grounding something. It should be connected to the bare ground from the panel and pigtailed to the ground screw also.

The breaker tripped because it senced a connection between the ground and the neutral. Some other path was able to carry a small voltage from whereever that green wire goes back to the ground screw.
 
  #5  
Old 07-30-06, 06:54 AM
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Since the white and bare wires are both under the gnd bar in the main panel wouldnt they be at the same potential?

If yes then why would the GFI trip, if its pigtail is at the same voltage potential as the neutral wire on its center screw?

Mike
 
  #6  
Old 07-30-06, 07:51 AM
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The green screw at the tub is most likely a bonding screw, whose purpose is to bond the tub and any metal objects together.
 
  #7  
Old 07-30-06, 09:59 AM
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Originally Posted by Michael7278
Since the white and bare wires are both under the gnd bar in the main panel wouldnt they be at the same potential?

If yes then why would the GFI trip, if its pigtail is at the same voltage potential as the neutral wire on its center screw?

Mike
Ah but in the case of a gfi thy are not. the neutral, if used must run through the gfi as well. The circuit board in the gfi does the majik
 
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