240V GFCI tripping with "ground" connected

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Old 12-22-12, 06:56 AM
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240V GFCI tripping with "ground" connected

I wired a hot tub to a 240 GFCI breaker. It only seems to work with the bare wire ground disconnected. If I connect the ground (which is connected to the same bar as the neutral (of course) the breaker trips instantly.
Essentially I have seen this happen before and just did not connect the ground wire. Instead I just left the ground disconnected and everything seemed to work fine. I'm just concerned about doing it right.
The bare ground is connected to the neutral bar at the hot tub as is the white neutral wire. Again, the white neutral is connected to the neutral bar at the box as is the white neutral wire.


Any advice?

Thanks
Ray
 
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Old 12-22-12, 07:55 AM
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The bare ground is connected to the neutral bar at the hot tub as is the white neutral wire
The first thing I'd suggest is to find the instructions that were packed with the 2 pole GFI breaker and read them because you have connected it incorrectly. The neutral wire of the circuit does not terminate on the neutral bus, but should terminate at the neutral lug on the GFI breaker and then, the white pigtail from the GFI breaker terminates on the neutral bus. By terminating the circuit neutral on the neutral bus I am surprised it works at all even without the ground wire connected. Connect it correctly and then connect the ground wire to the proper ground bar and try it again. Assuming this is the main service panel, yes, the ground wire can terminate on the main panel neutral bus.
 
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Old 12-22-12, 08:48 AM
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Hi Joe

I feel like an idiot. I did indeed wire it correctly. I just mis-stated it above. There are 4 wires coming from the tub. The 3 that are connected to the GFI breaker and one bare ground. They are connected properly (load/neutral/load) and the pigtail is connected to the neutral bar. With the bare ground disconnected, it works. With the bare ground connected it trips instantly.

Sorry I did not explain myself right. I have actually upgraded my own service in the past from 100 to 200 amp and had it inspected by an electrician who said I do beautiful neat work but I have always had difficulty understanding the concept of needing a ground wire when in fact the neutral seems to serve the same purpose and indeed they go to the same bar (not in the same lug).

Again...sorry for the improper description.

Ray
 
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Old 12-22-12, 09:06 AM
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Ahhh.....Ray.

Why you need a ground.
You have a device. In your case a spa. The heater element is connected across the 240 volt line and doesn't require a neutral.
You have a at least two motors...a blower and a circulating pump. Usually 120 volt motors. Makes sense to put one motor on one branch of the 240 v line and the the other on the other leg.

For example....the blower motor is connected red leg and neutral.
Circulating pump is connected black leg to neutral.

You've decided that since a neutral and ground are the same thing.....you do away with the ground since the neutral line can do both. Makes sense and will work fine.

Now.....either at the tub end or the panel end....the neutral falls out of the neutral bar. You turn on the circulating pump. Since you no longer have neutral and you decided not to use ground.....everything metal on the spa is now at 120 volt potential. The motor now creates a direct path from the black leg right to neutral.......and everything that should be grounded is live.

All hypothetical.....of course.....a ground MUST be used.


ON EDIT: Usually the cause of a GFI trip in a spa is a leaky heater. If I get a call when the breaker is tripping....the first thing I do is disconnect both of the heater lines.
 

Last edited by PJmax; 12-22-12 at 09:11 AM. Reason: testing
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Old 12-22-12, 11:18 AM
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I have always had difficulty understanding the concept of needing a ground wire when in fact the neutral seems to serve the same purpose and indeed they go to the same bar
They don't serve the same purpose or they would terminate at the same point on the equipment and they don't. Your equipment has a fault to ground and the GFI breaker is doing it's job. Your job is to find it, not disconnect it so it will work in an unsafe manner. PJ could very well be right, try disconnecting the heater and try it again.
 
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Old 12-22-12, 04:31 PM
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It's a 3 wire set up

I re-read the directions, it is a 240 volt but 3 wire, not 4. So, just out of curiosity, given the previous post, how does the system remain safe>

I thought I had posted the manual page. It does not show a ground, just the 2 hots and the neutral.
 
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Old 12-22-12, 06:13 PM
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I re-read the directions, it is a 240 volt but 3 wire, not 4. So, just out of curiosity, given the previous post, how does the system remain safe>

I thought I had posted the manual page. It does not show a ground, just the 2 hots and the neutral.
If there is no ground, tell me one more time about the ground you connected to the neutral bus, where does that come from?

If I connect the ground (which is connected to the same bar as the neutral (of course) the breaker trips instantly.
Yes, that one, the one that makes the GFI breaker trip till you disconnect it.
 
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Old 12-22-12, 06:21 PM
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I thought I had posted the manual page. It does not show a ground, just the 2 hots and the neutral.
More likley it is two hots and a ground.

Every spa I've wired has always had a ground. I can't remember if I've wired any just three wires.

Post a link to the spa mfg or leave me a make and model or at least the make and approx. year and we'll go from there.
 
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Old 12-22-12, 06:25 PM
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The wire that was run from the box to the tub had 4 wires. Red, black, white and bare ground. The directions to the tub don't show the use of a bare ground. I had run that ground from the Ground(neutral bar) at the tub to the neutral bar at the box. The White (neutral wire) at the tub was attached to the neutral bar at the tub and then to the breaker which pigtails to the neutral bar at the box. Essentially, both the bare ground wire and the white neutral were connected to the same terminal at the tub, only when it got to the box the white went to the breaker and the bare went to neutral bar. the tub is an Altamar

Here is the link to the instructions http://www.google.com/url?sa=t&rct=j...s5MoJw&cad=rja
 
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Old 12-22-12, 06:38 PM
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Essentially, both the bare ground wire and the white neutral were connected to the same terminal at the tub
Wrong ! The bare goes to its own lug......not to the neutral bar.
 
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Old 12-22-12, 06:44 PM
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both the bare ground wire and the white neutral were connected to the same terminal at the tub
And that's why your GFI breaker trips.
 
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Old 12-22-12, 06:47 PM
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On the wiring diagram in the manual I have the white going to the bar (TB3) and that goes back to the box to connect to the GFI breaker and then through the gfi pigtail to the neutral bar.

So where does the bare ground wire go in that diagram?
 
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Old 12-22-12, 06:50 PM
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I'm looking into your wiring now. Do you have a terminal block for only two wires and the ground block ?


Your spa is a 240 volt model only. It requires 2 hots and a ground.
A neutral is not required and wont be used
 
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Old 12-22-12, 06:54 PM
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Yes...that's what it has. What I wonder about is why there is no provision for the bare ground. In a prior post somone pointed out thatthis could be dangerous (not having one) since some of the pumps may be 110 v.
 
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Old 12-22-12, 06:59 PM
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Your spa is a 240 volt model only. It requires 2 hots and a ground.
A neutral is not required and wont be used
The ground wire goes to TB-3. The white wire is not connected at either end.
I looked up the schematic for your unit and it has a transformer on it to power the low voltage items.
 
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Old 12-22-12, 07:03 PM
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Thank you do much for your help. Looks like I'm OK then
 
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Old 12-22-12, 07:07 PM
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You are welcome. Happy holidays
 
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Old 12-22-12, 07:14 PM
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And the same to you PJmax....group members like you are what makes this a great place.
Wishing you and yours the best as well.
and thank you again
Ray
 
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