Well pump tripping GFCI

[EVpower]

A good point to start on a solution to your well pump tripping the Lightning ground fault protection is to see if the pump motor really has ground leakage current in excess of 6 mA. There have been a few reports of false PPOB GFCI trips with power tools. I don't think that is likely, but it is easy to check if the truck is correctly reporting a ground fault vs. motor starting load over current.

I found the well service technicians in my area do not connect the ground connection on the pump motor so a resistance check at the well head motor control box cannot be trusted.

I have an isolation transformer on the 240 volt PPOB output to our home transfer switch. The neutral connection is not used. The 3/4 HP well pumps have worked when needed under Lightning back up power.

Steve

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[v2h8484]

Since we are way outside my knowledge here, how best would you propose doing that? Should I open the generator inlet plug box and find a way to remove the ground wire? Should I attach that ground wire to something else? There are inline plugs for this too I believe, is that a better option?

Lastly and most importantly suppose; what are the results of this test I should expect? If things work after doing this is that indicating that the GFCI is the issue? I'm confused myself on that because I thought GFCI was based on the flow through the live and neutral wires.

I understand this is not a safe thing to do and not a permanent solution.

Disconnecting the ground from the truck in the generator inlet box is how I would do it. If the pump still won't start (and the truck trips) then inrush current is more likely the main problem. OTOH, if the pump starts and works fine then GFCI is more likely the main problem.

 

[hturnerfamily]

on the note about my camper...

since the camper can be easily powered, in full, by ProPower, when the camper is not coupled to the ball, and/or with the 12v 7pin cable plugged into the truck's trailer outlet, my situation is about why this would create a scenario where the ProPower 'sees' some type of fault, whether ground, or GFCI, or 'in rush', or whatever... it boggles the mind.

as for adding any type of startup 'softener' to the well's electrical box, that may not be that easy - while I added one to my 240v 30amp 3-ton air conditioner for my home, that was a way-easier job since there is already 'connections' there for it to easily be done...

 

[admo]

Disconnecting the ground from the truck in the generator inlet box is how I would do it. If the pump still won't start (and the truck trips) then inrush current is more likely the main problem. OTOH, if the pump starts and works fine then GFCI is more likely the main problem.

Thank you for the instructions. The result was the pump working correctly with the inlet box ground wire disconnected. So thankfully it looks like the cheaper option of a isolation transformer is plausible as a fix.

To provide good information for future reviewers a question to the experts who have helped me in this thread; would an isolation transformer have also solve the open neutral issue of the truck hookup? I've already got a neutral switching transfer switch myself so this is just documentation at this point.

 

[shelnian]

A lot of people just don't connect the ground wire, like when you install a three wire dryer. The neutral (white wire) and Lightning chassis are connected with a ground strap like the dryer so the Lightning chassis, like the dryer chassis, is grounded at your power panel.

 

[admo]

A lot of people just don't connect the ground wire, like when you install a three wire dryer. The neutral (white wire) and Lightning chassis are connected with a ground strap like the dryer so the Lightning chassis, like the dryer chassis, is grounded at your power panel.

If the truck is acting as the ground for the system and I remove that, where does everything in the house ground to? Or are you suggesting to disconnect the well's ground wire? It seems to make sense for an individual device because lighting will not strike my dryer.

Perhaps I do not understand the ground's purpose.

 

[shelnian]

If the truck is acting as the ground for the system and I remove that, where does everything in the house ground to? Or are you suggesting to disconnect the well's ground wire? It seems to make sense for an individual device because lighting will not strike my dryer.

Perhaps I do not understand the ground's purpose.

No, your truck isn’t the ground system. Your transfer switch should have it’s own ground rod that provides a ground for the circuits fed by your generator panel. The ground is a safety ground to ensure all metal surfaces (equipment chassis) don’t get hot and electrocute you if you touch it. I’m not an electrician and you should consult a professional before making any changes.

 

[chl]

A lot of people just don't connect the ground wire, like when you install a three wire dryer. The neutral (white wire) and Lightning chassis are connected with a ground strap like the dryer so the Lightning chassis, like the dryer chassis, is grounded at your power panel.

The DRYER example:

Since 2000, dryer outlets in new construction or upgrades have to be 4-prong.
If you add a 3-wire dryer to a new 4-prong outlet, you do not just leave the ground wire disconnected. However old 3-prong outlets in existing homes are grandfathered in.

The correct way to wire a 3-wire dryer to a 4-prong outlet/cord is to remove the ground strap that is connected to the neutral terminal in the 3-wire dryer ( the red circled area and the black arrow) and connect the ground wire from the 4-prong cord to the chassis ground screw (black arrow) where the ground strap was - the other 3 wires are connected as before, Hot, Neutral, Hot.
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Background
Three-prong plugs and outlets: Outlets with three slots have one ground slot and two live slots. They do not have a separate neutral slot; the ground is intended to act as both a neutral and a ground. This is an older configuration that was changed for safety.

The 3-prong cord has only two hot wires and one neutral wire—there is no separate ground wire. Such a configuration creates a chance of shock in the rare case that the ground wire opens up. The old 3-prong configuration would trip the breaker in the case of a short circuit, but in the broken ground condition, the entire bare ground and metal case would be energized. This was the reason the code changed to require the 4-wire configuration.
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Basic principles:

The dryer is a load, the Lightning is a source.

The neutral wire should only be grounded in one place, at the source, per code. In you house that would be at the main breaker panel. The neutral should not be grounded at sub-panels, out-buildings, etc.

The load should be grounded with a ground wire. (Exception is doubly insulated items like lamps.)

If you ground the neutral in two places, you will create a neutral return current path through the ground which will/should cause a ground fault current to be detected and the GFCI breaker to open.

If you have the neutrals grounded in two place (at the load and the Lightning) but try to solve the GFCI tripping problem by disconnecting the ground wire connection from the Lightning (source) to the house (load) you are creating a dangerous situation and neutral return current could pass through a person touching the Lightning chassis. It also is a violation of electrical code.

Yes, in such a situation it should cause the GFCI breaker to open, but a person could still get a shock before it opens. What if they have a pacemaker?

So the correct way to power a house with a bonded source (grounded neutral) like the Lightning, is to use a transfer switch that switches the load neutrals so that they are only grounded at the source, i.e., either the Lightning when it is connected as backup power (as shown below) or the main service panel when on utility power.

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As for the well pump...my 2 guesses:

1) Well pumps are in wet locations and it is possible and old one actually has a ground fault, neutral return current is leaking through the wet ground back to the source - the house breaker is not a GFCI so this does not open the circuit - the Lightning has GFCI protection so it opens the circuit. The neutral leakage current is traveling through the earth ground to the Lightning ground from the old well pump.

2) an old well pump might draw more start up current than the Lightning circuit can handle with the other loads (if any) on the circuits the Lightning is powering - if no other loads than more than the Lightning 30A circuit limit. Old pumps can draw more current due to wear and tear that occurs as the age.