Open Ground question

[DBECHEN]

Hi all, I have been having a problem with plugging into the shore power at our storage facility. They have all circuits run through GFCI outlets on the pole. When we plug in and we are not running anything the GFCI trips on the pole. We talked to our storage facility manager and they had an electrician come out and he said the issue was our RV having an open ground. We have a Progressive Industries surge protector that was installed by the first owner. When we plug into the 30 amp plug at our house and in campgrounds there is no problem. Any ideas what may be causing this? Thanks in advance.

[ScottG]

Tom/Barb wrote:

DBECHEN wrote:
Hi all, I have been having a problem with plugging into the shore power at our storage facility. They have all circuits run through GFCI outlets on the pole. When we plug in and we are not running anything the GFCI trips on the pole. We talked to our storage facility manager and they had an electrician come out and he said the issue was our RV having an open ground. We have a Progressive Industries surge protector that was installed by the first owner. When we plug into the 30 amp plug at our house and in campgrounds there is no problem. Any ideas what may be causing this? Thanks in advance.

You do not tell us what Amperage you are plugged into at the storage facility.

GFI protection is very rare for 30 AMP circuits So, I'd assume you are reduced to a lower amperage circuit like 15 AMP or maybe a 25 AMP circuit.

And your Surge protector may be having a problem with it.

I'm sorry to keep correcting you but your posts are only confusing the matter.
An EMS has no idea what the circuit's current rating is and it doesn't care.
So a 30A EMS does not know it's on a 15A circuit and and that has no bearing on it anyway. The circuits current rating has no correlation to ground fault sensitivity.

[ktmrfs]

another likely culprint. the outside outlet on the trailer and the kitchen outlets in the trailer should be on a GFI circuit. turn off that circuit. either at the panel breaker in the trailer or at the GFI outlet usually in the bathroom.
any moisture in the outside outlet can lead to a GFI trip. and slight variations in trip limits could cause the 30AGFI to trip but not the bathroom/outside GFI.

And if it trips with even the trailer 30A main panel breaker off, I'd look very carefully at the wiring to the PO installed surge protector circuit.

I have a sneaking suspicion the cause is one of the following
bad wiring to the surge protector
leakage at the fridge heater if the fridge is on
leakage at an outside outlet in the trailer
lastly, someone doing some bad rewiring in the trailer panel

I wired my 30A 120V circuit in the house for trailer power with a 30A GFI breaker. In over 5 years it has never tripped for a GFI fault, and I would never expect it to unless there is a fault somewhere.

[Tom_Barb]

ktmrfs wrote:


only if the house circuit is on a GFI. and in most houses GFI is on outside circuits, bathroom circuits, and kitchen circuits. a garage circuit usually is not on a GFI, so make sure you plug into a GFI Circuit.

All house circuits are on breakers, If there is a short in the trailer it will pop the breaker.

we know where the GFIs are required.

[Tom_Barb]

DBECHEN wrote:
Hi all, I have been having a problem with plugging into the shore power at our storage facility. They have all circuits run through GFCI outlets on the pole. When we plug in and we are not running anything the GFCI trips on the pole. We talked to our storage facility manager and they had an electrician come out and he said the issue was our RV having an open ground. We have a Progressive Industries surge protector that was installed by the first owner. When we plug into the 30 amp plug at our house and in campgrounds there is no problem. Any ideas what may be causing this? Thanks in advance.

You do not tell us what Amperage you are plugged into at the storage facility.

GFI protection is very rare for 30 AMP circuits So, I'd assume you are reduced to a lower amperage circuit like 15 AMP or maybe a 25 AMP circuit.

And your Surge protector may be having a problem with it.

[ktmrfs]

Tom/Barb wrote:
An other way to test this is to. reduce the 30 AMMP trailer plug to 15 AMP power cord and plug it into a wall plug at home.
If it pops the breaker it is the trailer.

then find the trailer's breaker box, and trip all breakers and pug it in again. see what happens. Nothing?
then reset one breaker at a time until you know which will trip the house breaker.

If the trailer doesn't trip the 30 amp breaker at home, I doubt it is the trailer.

only if the house circuit is on a GFI. and in most houses GFI is on outside circuits, bathroom circuits, and kitchen circuits. a garage circuit usually is not on a GFI, so make sure you plug into a GFI Circuit.

[DBECHEN]

D.E.Bishop wrote:

DrewE wrote:

ktmrfs wrote:

open ground will NOT trip a GFI. A GFI is designed to work with a circuit that is not grounded, e.g. the old two prong plug.

there are TWO things that will cause a GFI to trip.

1) unbalanced current between the hot and neutral.
2) ground neutral short. e.g. somewhere downstream the ground and neutral are touching.

now a regular 30A RV circuit most often does NOT have a GFI, so no issue.

couple of things that could be causing an issue.
1) leakage in the fridge 120V element to ground.

one way to check is to turn OFF every breaker in the RV. GFI should Not trip. if it does, the fault is before the 30A main breaker. If no GFI trip, trip each circuit and see which one trips the GFI. whatever circuit trips the GFI tells you which circuit either has excessive leakage current or a ground neutral short.

This is one of the best responses to the question; there are a lot of confused people who seem not to understand what a GFCI detects and what it does not detect.

If you have leakage from hot to ground, shutting off the breakers will help track that down. If there's a short or partial short between neutral and ground, shutting off the breakers will not take that away (they only shut off the hot side) and you're left with the job of hunting it down. These can be rather tricky to find, either in a house or in an RV, but it's a definite safety hazard under certain fault conditions such as an open ground connection and should be corrected.

There is also a small chance that there is sufficient leakage from ordinary noise suppression and other input conditioning circuits on the various electrical devices in the RV which, if taken individually, would not be sufficient to trip the GFCI. This would only affect things with three prong plugs. In most cases it's more productive to assume that this is not the cause and look for other problems.

I suggest you read the two posts that I have quoted and at the first opportunity follow the suggestions given in the first quoted post.

This problem seems to come up once or twice a year and is usually a common touching a ground or a ground common reversal.

Thanks for the explanation. Gives me something to check this week.

[ScottG]

Tom/Barb wrote:
If it is the trailer, when plugged into the house 30 amp plug. the trailer should have popped a breaker in the trailer master breaker panel.

I dont understand why you keep posting that - you are dead wrong and it is not helping the OP. You can have a massive ground fault and it wont pop a normal breaker.
That's what they created GFCI's for!

[Tom_Barb]

Like
I said at the start. If it works every where except the storage facility I'll bet on the storage facility wiring is bad.

[DBECHEN]

ScottG wrote:

Tom/Barb wrote:

ScottG wrote:
Of course you have an open ground. Your ground isn't supposed to be bonded and none of that matters anyway. A GFCI doesn't trip because of an "open ground".
Somewhere, you have a leakage to ground. Could be a wet outside receptacle, bad fridge heater *even if it works fine) or water heater or even a bad microwave (rare). I would unplug the appliances and see if the fault remains.

If that was his problem, plugging it at home would pop the breaker.

No, it would not because a GFCI fault is not an overload.

OP, another thing that can cause it is a failing converter. I would turn off its breaker and see if it still trips the GFCI.

I will try that. Thanks. Will try unplugging fridge, microwave, water heater as well.

[Tom_Barb]

If it is the trailer, when plugged into the house 30 amp plug. the trailer should have popped a breaker in the trailer master breaker panel.

DID IT?

If the short was between the trailer 30 amp plug, and the trailer master breaker panel It would have popped the 30 Amp breaker at the house.

[ScottG]

D.E.Bishop wrote:

DrewE wrote:

ktmrfs wrote:

open ground will NOT trip a GFI. A GFI is designed to work with a circuit that is not grounded, e.g. the old two prong plug.

there are TWO things that will cause a GFI to trip.

1) unbalanced current between the hot and neutral.
2) ground neutral short. e.g. somewhere downstream the ground and neutral are touching.

now a regular 30A RV circuit most often does NOT have a GFI, so no issue.

couple of things that could be causing an issue.
1) leakage in the fridge 120V element to ground.

one way to check is to turn OFF every breaker in the RV. GFI should Not trip. if it does, the fault is before the 30A main breaker. If no GFI trip, trip each circuit and see which one trips the GFI. whatever circuit trips the GFI tells you which circuit either has excessive leakage current or a ground neutral short.

This is one of the best responses to the question; there are a lot of confused people who seem not to understand what a GFCI detects and what it does not detect.

If you have leakage from hot to ground, shutting off the breakers will help track that down. If there's a short or partial short between neutral and ground, shutting off the breakers will not take that away (they only shut off the hot side) and you're left with the job of hunting it down. These can be rather tricky to find, either in a house or in an RV, but it's a definite safety hazard under certain fault conditions such as an open ground connection and should be corrected.

There is also a small chance that there is sufficient leakage from ordinary noise suppression and other input conditioning circuits on the various electrical devices in the RV which, if taken individually, would not be sufficient to trip the GFCI. This would only affect things with three prong plugs. In most cases it's more productive to assume that this is not the cause and look for other problems.

I suggest you read the two posts that I have quoted and at the first opportunity follow the suggestions given in the first quoted post.

This problem seems to come up once or twice a year and is usually a common touching a ground or a ground common reversal.

Well put and this is exactly why I suggested disconnecting those items.

[D_E_Bishop]

DrewE wrote:

ktmrfs wrote:

open ground will NOT trip a GFI. A GFI is designed to work with a circuit that is not grounded, e.g. the old two prong plug.

there are TWO things that will cause a GFI to trip.

1) unbalanced current between the hot and neutral.
2) ground neutral short. e.g. somewhere downstream the ground and neutral are touching.

now a regular 30A RV circuit most often does NOT have a GFI, so no issue.

couple of things that could be causing an issue.
1) leakage in the fridge 120V element to ground.

one way to check is to turn OFF every breaker in the RV. GFI should Not trip. if it does, the fault is before the 30A main breaker. If no GFI trip, trip each circuit and see which one trips the GFI. whatever circuit trips the GFI tells you which circuit either has excessive leakage current or a ground neutral short.

This is one of the best responses to the question; there are a lot of confused people who seem not to understand what a GFCI detects and what it does not detect.

If you have leakage from hot to ground, shutting off the breakers will help track that down. If there's a short or partial short between neutral and ground, shutting off the breakers will not take that away (they only shut off the hot side) and you're left with the job of hunting it down. These can be rather tricky to find, either in a house or in an RV, but it's a definite safety hazard under certain fault conditions such as an open ground connection and should be corrected.

There is also a small chance that there is sufficient leakage from ordinary noise suppression and other input conditioning circuits on the various electrical devices in the RV which, if taken individually, would not be sufficient to trip the GFCI. This would only affect things with three prong plugs. In most cases it's more productive to assume that this is not the cause and look for other problems.

I suggest you read the two posts that I have quoted and at the first opportunity follow the suggestions given in the first quoted post.

This problem seems to come up once or twice a year and is usually a common touching a ground or a ground common reversal.

[ScottG]

Tom/Barb wrote:

ScottG wrote:

Tom/Barb wrote:

ScottG wrote:


That's not the case. It trips all the GFCI's at the facility but is ok on a standard 30A (no GFCI).

We do not know all the GFIs at the storage facility are good. they are probably all on the same circuit. and wired wrong.

a cheap tester will eliminate the doubt.

to determine if it is the trailer, simply read continuity between the two hot leads and the common ground on the trailer plug, it should show and open.

If it doesn't show an open circuit, it would pop the 30 amp breaker at home or smoke something.
.

If a GFCI is wired wrong in any way, it will not work (trip) under any circumstances.

but it can be wired wrong and work
we don't know if this is a new build. and if any trailer has worked as wired.
We also don't know if this is a new trailer.

I'm sorry Tom but you are mistaken. A miswired GFCI will not trip.

[Tom_Barb]

ScottG wrote:

Tom/Barb wrote:

ScottG wrote:


That's not the case. It trips all the GFCI's at the facility but is ok on a standard 30A (no GFCI).

We do not know all the GFIs at the storage facility are good. they are probably all on the same circuit. and wired wrong.

a cheap tester will eliminate the doubt.

to determine if it is the trailer, simply read continuity between the two hot leads and the common ground on the trailer plug, it should show and open.

If it doesn't show an open circuit, it would pop the 30 amp breaker at home or smoke something.
.

If a GFCI is wired wrong in any way, it will not work (trip) under any circumstances.

but it can be wired wrong and work
we don't know if this is a new build. and if any trailer has worked as wired.
We also don't know if this is a new trailer.

[ScottG]

Tom/Barb wrote:
An other way to test this is to. reduce the 30 AMMP trailer plug to 15 AMP power cord and plug it into a wall plug at home.
If it pops the breaker it is the trailer.

then find the trailer's breaker box, and trip all breakers and pug it in again. see what happens. Nothing?
then reset one breaker at a time until you know which will trip the house breaker.

If the trailer doesn't trip the 30 amp breaker at home, I doubt it is the trailer.

Again, a ground fault is not going to cause a normal breaker to trip.