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.
---
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.
----
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.

 

[admo]

Thank you for the detail chl, I knew I was out of my depth when this thread started and now people with more knowledge on electricla systems are debating each other so I don't have much to do. I acknowledge and agree removing the ground wire is a bad idea, I did it only to run the experiment mentioned earlier to attempt to figure out if the issue was the inrush current or a real GFCI fault, as you also identified with your 2 guesses.

Removing the ground wire allowed the pump to operate from the truck's power, which I believe means this is a true GFCI fault. I was intending to hiring my local electrician to install the isolation transformer maquis recommended in the first reply.

This thread has provided the help I really needed, a logical discussion of the data points, a method to test the hypothesis, an answer to what the problem was, and a solution. I will certainly return to finish the thread with the results once the electrician installs the isolation transformer but as we head into the holidays that could be awhile.

 

[chl]

Thank you for the detail chl, I knew I was out of my depth when this thread started and now people with more knowledge on electricla systems are debating each other so I don't have much to do. I acknowledge and agree removing the ground wire is a bad idea, I did it only to run the experiment mentioned earlier to attempt to figure out if the issue was the inrush current or a real GFCI fault, as you also identified with your 2 guesses.

Removing the ground wire allowed the pump to operate from the truck's power, which I believe means this is a true GFCI fault. I was intending to hiring my local electrician to install the isolation transformer maquis recommended in the first reply.

This thread has provided the help I really needed, a logical discussion of the data points, a method to test the hypothesis, an answer to what the problem was, and a solution. I will certainly return to finish the thread with the results once the electrician installs the isolation transformer but as we head into the holidays that could be awhile.

You'd be surprised how many people remove the ground wire from the Lightning to stop the GFCI tripping and leave it like that and think it's safe!

The Lightning GFCI is very sensitive as others pointed out which makes it had to decide if it is a true ground fault, RF on the line inducing a current due to whatever device it is powering, or if the Lightning inverter has a problem and is not producing a pure enough sine wave to power an electrical blanket.

You or your electrician should look at the pump wiring to see if there is an obvious source of a ground fault, frayed insulation, etc.

From what I have read tonight about well pumps, if they are on GFCI protected circuits there is a lot of nuisance tripping. They will last from 8 to 15 or up to 25 years. They are prone to ground faults due to water intrusion into the electrical parts (e.g., motor) through seals as they age. There are rebuild kits. It could also be faulty insulation on the wiring to the pump causing a ground fault.

"I suspect that the pump is the problem. If it is a model worthy of messing with replacing the seals or rebuilding may be justified. A few times I have had luck opening up the pump, drying it out and resealing it with a rebuild kit or, if needed, silicon sealant, Form-a-gasket or similar.

Shortening the cord a few inches allows a less worn portion of the cord to make a better seal. Sometimes it works. Other times not. Often you can squeeze out another year or so out of the pump. Seldom is it worth the trouble on anything less than a 1HP industrial model.

The most common spot to leak is around where the cord goes into the pump body. Particularly if the cord is used to move the pump. Always use a rope rigged to keep some slack in the cord near the pump...."

An Isolation transformer should do the trick if a ground fault it the issue and not a rush current.

In case you are interested, this explains isolation transformers: https://www.powerinspired.com/isolation-transformer-need-know/

These diagrams explain how it works where there is a dangerous ground fault (top circuit).

BTW, an isolation transformer will also filter out any HF noise on the lines in case that is the problem tripping the GFCI.

Good luck.

 

[admo]

Thanks chl, I had found the same page you linked and gave it a read. One question for future readers I had is if an isolation transformer would have solved the open neutral issue. As I had understood it the issue was the truck has a ground and the house has a ground, meaning the return voltage is split between the two and the GFCI doesn't love that. So everyone with Lightnings is putting in neutral switching transfer switches, but since the isolation transformer physically disconnects these would this also solve the problem?

I wonder if the isolation transformer is an alternative solution for open neutral generators versus a neutral switching transfer switch and one that eliminates some additional problems like I am having here.

 

[v2h8484]

I wonder if the isolation transformer is an alternative solution for open neutral generators versus a neutral switching transfer switch and one that eliminates some additional problems like I am having here.

If you mean "bonded neutral generators" then yes, the transformer eliminates the need for a neutral switching transfer switch. For open/floating neutral generators, only a regular non-neutral switching transfer switch is needed.

 

[chl]

Thanks chl, I had found the same page you linked and gave it a read. One question for future readers I had is if an isolation transformer would have solved the open neutral issue. As I had understood it the issue was the truck has a ground and the house has a ground, meaning the return voltage is split between the two and the GFCI doesn't love that. So everyone with Lightnings is putting in neutral switching transfer switches, but since the isolation transformer physically disconnects these would this also solve the problem?

I wonder if the isolation transformer is an alternative solution for open neutral generators versus a neutral switching transfer switch and one that eliminates some additional problems like I am having here.

The issue is the house has a grounded neutral and the truck has a grounded neutral so return current (on the neutral) has another path back to the source through the ground which means some of the current on the neutral is diverted which is sensed by the GFCI which compares the current on the Hots and the current on the neutral and if they are unequal by a few milliamps, the GFCI detects a ground fault condition and opens.

The transfer switch switches the designated house branch circuits from neutrals bonded in the house panel, to neutrals grounded in the source (generator of Lightning). The branch circuits switched by the transfer switch and connected to the Lightning still have a ground, a grounded neutral and hot(s) connections.

The isolation transformer will eliminate the GFCI tripping problem for a single device, like your pump because no fault current would get back to the truck since the load/pump is isolated electrically from ground by the transformer.

However, some things to consider if you would try to use it to power a house panel with branch circuits.

Code requires house branch circuits to have grounded neutrals, but the isolation transformer does not provide that. The transfer switch does - the neutrals are grounded at the Lightning or generator.

If one of the lines of the isolation transformer (say the line attached to your house neutrals) were grounded in compliance with code, it would provide a path back to ground and defeat the 'isolation" desired. So you would have to unbond those neutrals in the house panel anyway to avoid tripping.

Electrical codes generally would not allow an isolation transformer to be the sole power source for a dwelling because of the lack of a grounded neutral connection, which is necessary for proper operation of most household appliances and safety devices like in-house GFCIs. There may be exceptions in the code for homes under construction and unoccupied.

As I mentioned If you leave the neutrals grounded at the main panel, then there is a ground path back to the Lightning and the isolation transformer is useless.

Also, a short circuit fault in the load circuit will not trip the truck GFCI and shut off the source power, so some additional protection has to be present in the output circuit so that a short will shut off power from the transformer load side - e.g., another breaker house panel which would not be code compliant due to needing to have ungrounded neutrals. The transfer switch has inherently a subpanel that is code compliant when connected to the generator or Lightning properly.

Even if you somehow found a way around those issues, isolation transformers are not lossless, so some significant power will be lost to heat from the resistance of the windings - not an issue with a transfer switch. And isolation transformers are relatively expensive.

When transformers fail the can cause a fire, explosion. etc.

So, no, not a good solution to the problem.

 

[admo]

Thanks again chl, now I know what to expect when the electrician calls me back. I told the receptionist I wanted an isolation transformer installed between the generator plug and the panels but as you point out this is not realistic.

v2h8484 you are right, we are fortunate to have so many experts in the field willing to help us out on these forums.

Well an expensive solution but a necessary one for toilets when the power is out.

 

[Maquis]

Thanks chl, I had found the same page you linked and gave it a read. One question for future readers I had is if an isolation transformer would have solved the open neutral issue. As I had understood it the issue was the truck has a ground and the house has a ground, meaning the return voltage is split between the two and the GFCI doesn't love that. So everyone with Lightnings is putting in neutral switching transfer switches, but since the isolation transformer physically disconnects these would this also solve the problem?

I wonder if the isolation transformer is an alternative solution for open neutral generators versus a neutral switching transfer switch and one that eliminates some additional problems like I am having here.

Yes, it would. In fact, the transformer I linked would not even be connected to the truck’s neutral - there’s no place to put it!

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