Whirlpool GFI -- Stumper

There's an error in the diagram

If you look carefully at the diagram, you'll see they've got one of the hot lines from the CB going to the ground screw in the junction box. I'm going to assume your electrician wired things correctly, however.

Also, this CB can be used for either a 2-wire or 3-wire circuit. When used in a 2-wire circuit, the neutral connection is unused. This bothers me some, but I can't say why, other than unterminated connections bother me in general. I'd connect a 24Kohm, 1 Watt resistor across each hot-to neutral pair to provide a constant drain currrent of about 5ma. This is, needless to say, another straw to grasp.

Another question: Is there a separate ground rod at the whirlpool, or does everything go back to the service ground?

And another: Is the cable from the main panel to the CB panel at the whirlpool a 2-wire or 3-wire (plus ground)? I.E., is the neutral bus in the remote panel connected to anything?

ked said:

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.

Click to expand...

That's a strong possibility, given that Bob1234 is reasonably certain that the problem occurs only if the whirlpool was run, and is why I suggested disconnecting the downstream circuit from the breaker as a test. Using a switch is a nicety . I'd love to see a circuit diagram of that controller, but I won't hold my breath.

I'd still like to know if an upstream problem can trip a GFCI -- don't see why not -- and would continue to pursue that if all else fails.

Mikey said:

If you look carefully at the diagram, you'll see they've got one of the hot lines from the CB going to the ground screw in the junction box. I'm going to assume your electrician wired things correctly, however.

Also, this CB can be used for either a 2-wire or 3-wire circuit. When used in a 2-wire circuit, the neutral connection is unused. This bothers me some, but I can't say why,

Click to expand...

Because you dont understand how it works?

Mikey said:

other than unterminated connections bother me in general. I'd connect a 24Kohm, 1 Watt resistor across each hot-to neutral pair to provide a constant drain currrent of about 5ma. This is, needless to say, another straw to grasp.

Click to expand...

WHY? Call Kohler back to get the POS tub out of my house.

Mikey said:

Another question: Is there a separate ground rod at the whirlpool, or does everything go back to the service ground?

Click to expand...

Would would that change?

Mikey said:

And another: Is the cable from the main panel to the CB panel at the whirlpool a 2-wire or 3-wire (plus ground)? I.E., is the neutral bus in the remote panel connected to anything?

Click to expand...

Another what would that change?

Chris75 said:

Because you dont understand how it works?

Click to expand...

Probably. I do know basically how the CB works, but I don't know if it's possible for the unterminated neutral to develop a transient that might trigger the trip. I suspect not, since this is low-impedance stuff, but I do know that some 2-wire GFCIs don't run the (unused) neutral through the sensing toroid; maybe there's a reason for that. Maybe Square D decided that they could save a few bucks by using one breaker for both 2-wire and 3-wire applications. Maybe they were wrong.

Chris75 said:

WHY? Call Kohler back to get the POS tub out of my house.

Click to expand...

Because I like to understand what causes a problem, rather than simply making the problem go away.

If you install a switch between the GFCI and the tub it will solve the tripping problem. And indicate a Kohler control panel problem.

ked said:

If you install a switch between the GFCI and the tub it will solve the tripping problem. And indicate a Kohler control panel problem.

Click to expand...

Is that really the answer? How bout Kohler find the actual problem and fix it?

Assuming that it is a Kohler problem, I'm sure they are working on fixing the electric current leak in their control panels. But it will be a wait for the replacement part. In any case, the switch must be installed.

Bob1234 said:

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

Click to expand...

Not necessarily... if it's a design issue then every replacement will behave in exactly the same way. OTOH, presumably your problem is unique in Kohler's eyes, so there's something in your particular installation contributing to the problem.

I'd still try disconnecting the whirlpool altogether after running it, either via a switch or just by disconnecting the hot leads at the breaker. I'd also pester Kohler to see if they would give you a schematic diagram of the control box -- or take it apart and reverse-engineer it as much as possible -- to see what kind of interface it presents to incoming power.

Chris's early comment to get somebody with a megger out there is a good idea, and probably the easiest thing to try to find some quantitative explanation of what might be going on.

Well... I think the best option is to have someone come out with a megger. I appreciate everyone's thoughts and suggestions. FYI, it cannot be a Kohler problem because the problem does not seem to exist except on my system. We've contacted Kohler and spoke with their electrical engineering division to check this. There is, it seems, something in our setup that, even though it follows Kohler's schematic, we're still getting GFI trips. I was sorta hoping that someone would have seen this before, but I guess its more unique to this setup. We'll keep working on it, but if anyone has any more ideas, please post them as I'm following the thread.
Bob

Bob1234 said:

FYI, it cannot be a Kohler problem because the problem does not seem to exist except on my system.
Bob

Click to expand...

I see these types of problems all the time with hot tubs, usually its the recirc pump, The gfi will only trip with current leakage, so something is not right in your tub. Now, it very well could be a problem before the tub, but only a megger would be able to answer that question.


Please keep us posted on your findings.

I sure hope it's a constant leakage, rather than a time-dependent fault of some kind, or the megger driver is going to get very tired of waiting around for something to happen. I'm surprised that Kohler's EEs couldn't offer some insight. Hmmm. Make that disappointed, not surprised . I'd see if I could talk Kohler into sending out a 3-channel logger or recording oscilloscope of some kind with sensitive current probes that could monitor both legs of the GFI circuit and the ground a few times per second for up to 12 hours.