Whirlpool GFI -- Stumper

This GFI issue is stumping several electricians, so any help is appreciated:

Kohler Memoirs Whirlpool using a dedicated GFI A 220-240V, 20A, 50/60 Hz.. The wiring properly follows Kohler’s wiring instructions.

• Whirlpool was connected to a dedicated GFI in the main breaker panel. The GFI typically tripped several hours after the whirlpool was used and reset without problem.
  
• The GFI breaker was replaced.
  
• After continuing GFI trips, all the wiring from the main panel to the whirlpool was replaced and re-checked. But, GFI kept tripping.
  
• The main wiring to the house was checked by the electric company. No leakage.
  
• The whirlpool motor/circuit board was replaced. No change.
  
• The GFI was moved from the main panel to a separate box within the whirlpool enclosure (in order to decrease the 50 ft. distance between the whirlpool and the main panel). No change.
  
• The entire whirlpool was replaced. No change.

So, I’ve got a dedicated GFI that always trips several hours after the whirlpool is run. It is not the whirlpool. It is not the GFI. There does not seem to be a short, because the breaker resets without incident after it trips, and remains reset until several hours after the whirlpool is run; that is, it trips when there is no apparent load to the whirlpool.

Any thoughts would be appreciated. A solution would be even better.

Bob

Bob1234 said:

This GFI issue is stumping several electricians, so any help is appreciated:

Kohler Memoirs Whirlpool using a dedicated GFI A 220-240V, 20A, 50/60 Hz.. The wiring properly follows Kohler’s wiring instructions.

• Whirlpool was connected to a dedicated GFI in the main breaker panel. The GFI typically tripped several hours after the whirlpool was used and reset without problem.
  
• The GFI breaker was replaced.
  
• After continuing GFI trips, all the wiring from the main panel to the whirlpool was replaced and re-checked. But, GFI kept tripping.
  
• The main wiring to the house was checked by the electric company. No leakage.
  
• The whirlpool motor/circuit board was replaced. No change.
  
• The GFI was moved from the main panel to a separate box within the whirlpool enclosure (in order to decrease the 50 ft. distance between the whirlpool and the main panel). No change.
  
• The entire whirlpool was replaced. No change.

So, I’ve got a dedicated GFI that always trips several hours after the whirlpool is run. It is not the whirlpool. It is not the GFI. There does not seem to be a short, because the breaker resets without incident after it trips, and remains reset until several hours after the whirlpool is run; that is, it trips when there is no apparent load to the whirlpool.

Any thoughts would be appreciated. A solution would be even better.

Bob

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I would hire someone with a megger to find the problem. There is obviously current leakage, did you say they replaced the motor?

Yes, the motor was replaced. Still tripped GFI. Eventually, the entire whirlpool was replaced.
Bob

I would say the problem lies with Kohler, have them troubleshoot the problem or ask for your money back, How many electricians have actually looked at the problem? And did any of them use a megger?

Is there any way a leak could eventually allow water into the electrical stuff, particularly at or before the switch that turns on the whirlpool?

Mikey said:

Is there any way a leak could eventually allow water into the electrical stuff, particularly at or before the switch that turns on the whirlpool?

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They use air switches, so its pretty impossible.

There are no leaks. Its not Kohler, because they already replaced the whirlpool and the GFCI still trips after the tub has been run. We had the same thought, which is why the whirlpool was replaced. I'm open to all ideas to troubleshoot this problem.
Bob

Bob1234 said:

There are no leaks. Its not Kohler, because they already replaced the whirlpool and the GFCI still trips after the tub has been run. We had the same thought, which is why the whirlpool was replaced. I'm open to all ideas to troubleshoot this problem.
Bob

Click to expand...

I gfi will just not trip, either a problem with the wiring to the tub, or the tub itself. The only way to fix this is to hire someone that knows what they are doing.

Does this tub have heaters ?

Some questions, a couple of experiments to try, and a last-minute Q for the pros

1) How long does it take for the breaker to trip after the whirlpool is shut off? Is this a pretty constant value? Does it occur at a particular time of day (or night)?

2) Can you think of any other electrical event that might be occuring when the breaker trips? E.g., whirlpool heater comes on, well pump comes on, AC comes on, security lighting comes on, big sodium-vapor light in the yard comes on, etc. As an experiment, you could try turning off every other breaker in the main panel to ensure the whirlpool circuit is the only one energized. It'd be a good excuse for a candlelight take-out dinner.

3) Please describe the entire circuit from the breaker to the whirlpool in excruciating detail. What kind of cable are you using? Is it in conduit (metal or plastic)? Are there any other electrical cables running parallel to the whirpool's cable?

Let's assume it's something like

Breaker -> cable A -> device A -> cable B -> device B -> etc.

Now the other experiment. This is a "don't try this at home" kind of thing, but it's what I would do. Run the whirlpool. Immediately disconnect cable A at the breaker panel. If the breaker eventually trips, well, the only thing involved now is the breaker and the upstream circuit to the main panel. If it doesn't, the problem lies downstream somewhere.

If the breaker doesn't trip, move one step downstream and try again with a longer circuit -- i.e., do your disconnecting on the far end of Wire A, then the near end of Wire B, the far end of Wire B, etc. Keep going until you've found the point in the circuit where you've just brought in the portion of the circuit that "causes" the breaker to trip.

Keep in mind what causes a GFI breaker to trip. It's continually sensing the current going out the "hot" wire, and comparing that to the current returning on the neutral. If this is a 240V "dual" breaker, it compares the outbound current in one leg with the inbound current in the other. If it's a combined 240/120 circuit, there is some pretty fancy computing going on as it looks at both hot legs and the neutral. If the total outbound and inbound currents differ by .005A, the breaker trips. It doesn't wait long to see if the differential is a transient or a real fault -- if the current differential lasts for something like 25 ms, the breaker trips.

From what you've said so far, I'm assuming you've got something like a 12-2 W/G cable running from the breaker. (I couldn't find Kohler's installation instructions on their website, but that's what you need, based on your description.) The only reason for a good breaker to trip is for a current differential as described above to occur. Something, somewhere, is causing that current differential. If another circuit's cable were running parallel to the whirlpool's cable for any length, it might be possible for a large, sudden load in the other circuit to induce enough of a current in one leg of the whirpool cable to cause the breaker to trip. It would take a pretty special topology and current pattern to do this, but hey -- we're looking for straws to grasp here.

Here's a question for the pros here: is it possible for an upstream event (e.g., an induced spike on one leg of the service entrance) to provoke a GFCI to trip? I don't see any theoretical reason why not. If all else fails, I'd pull the main breaker and see what happens.

Mikey, let me try to answer these as best I can:
1. Breaker trips anywhere from 2 to 10 hours after the whirlpool motor stops. Time of day does not matter.
2. I've turned every major device on/off while the whirlpool is running; e.g. AC, Washer, Dryer, etc. Nothing else affects the whirlpool GFI one way or the other.
3. After moving the GFI from the main panel, there is now a regular 20A breaker in the main panel, which is connected to a small breaker panel with a 220-240v 20A double GFI breaker, which then connects to the whirlpool. When I say "double" it appears to be two 120v breakers that are combined into one GFI with a cross-bar connecting the two switches. It goes in as one unit. I believe it is a Square D. This sub-panel is located at the whirlpool. The wiring between the main panel (romex?) and the sub-panel is the correct gage for a 20A circuit. Aside from the wiring in the main panel, no other wire runs parallel to the wire feeding the GFI or to the tub.

The problem with disconnecting other circuits is the time-delay for the GFI to trip. It is usually 2-10 hours, but its also been longer -- but never shorter. However, nothing else in the home acts in this manner, nor do any other appliances appear to affect the whirlpool one way or another.

I'll try to upload the Kohler wiring diagram.

Bob

Can you post a picture of the subpanel and double GFCI breaker?

No rush -- it's past my bedtime.

Electric Diagram

Uploaded electric diagram

The problem is outlined in the installation instructions just under the diagram.
Here it clearly states to have this piece of equipment installed by a licensed electrician. It will not work properly until a licensed electrician has been hired to make the installation.

jwelectric said:

The problem is outlined in the installation instructions just under the diagram.
Here it clearly states to have this piece of equipment installed by a licensed electrician. It will not work properly until a licensed electrician has been hired to make the installation.

Click to expand...

That was too funny.

Chris75 said:

That was too funny.

Click to expand...

Yeah, and I'll bet his neutral is in the center of the panel, not on the left side as shown in the diagram.

Seriously... here's a silly question: Are you certain the whirpool has to have run for the CB to trip? The trip occurs so long after the whirlpool was shut off, I'm wondering if the running and tripping are related at all.

Also... I asked for a picture of the breaker earlier -- the exact Square D model number would be sufficient.

Picture Upload

Here's a photo of the GFI. I "think" its a Square-D "HOM 2-pole GFI." As far as being associated with running the Whirlpool -- guess I don't have a good answer. If the Whirlpool is run, the GFI goes off several hours later. If I reset it and don't run the Whirlpool, it does not go off. So, it seems that the two are related, but I don't know enough to be sure.

Bob

The problem is in the control panel for the tub. Install a 240 v. switch downstream from the GFCI and upstream from the control panel. I think this will eliminate the tripping and prove that it is a Kohler problem. If it does not eliminate the tripping then I am stumped. So either live with the switch or pursue Kohler for another control panel. I have a similar tub with no control panel, just switches.

good idea

The problem is outlined in the installation instructions just under the diagram.
Here it clearly states to have this piece of equipment installed by a licensed electrician. It will not work properly until a licensed electrician has been hired to make the installation.

Now if we can just get plumbing manufacturers to make their items so they won't work unless installed by a LICENSED plumber, we can put HD and Lowes out of business. Since that whirlpool is by Kohler and they seem to have perfected the electrical part of that, maybe they are also working on the plumbing side and just have a couple of bugs to work out.

Ken, the first whirlpool had the motor/control panel replaced, but still tripped GFI. This is the second whirlpool, brand new. We're already explored this as a Kohler issue, but given that this is the second tub, with the same GFI problem, I don't think that it is a Kohler issue.
Bob

This is why I labeled this as a "stumper." I've had several electricians look at this, and several plumbers, all of whom are stumped. Its been suggested that some GFI are sensitive where motors are involved, that nuisance trips can occur, etc. But, while the professionals are suggesting possible causes, no one can figure it out, or provide a solution. So, I'm hoping that by expanding this issue to many more professionals, someone will have seen this before or had an idea as to how to solve it.
Bob