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gunns

Unfortunately - Peoples Republic of California

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Posted: 05/16/12 03:56pm Link  |  Quote  |  Print  |  Notify Moderator

First off, when I parked the trailer a while back I turned the 120v power to the water heater off.

With the main breaker on and all the others off and the trailer power plugged into a house GFI circuit everything seems to be fine. The house GFI does not trip. As soon as I turn on any of the trailer branch circuit breakers and power is drawn through that circuit the house GFI trips

If I plug the trailer power line into a house non-GFI circuit everything appears to work properly.

Any ideas?

Fire Instructor

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Posted: 05/16/12 03:58pm Link  |  Quote  |  Print  |  Notify Moderator

Dave - Sparky is right on the money with his advice. Try to isolate, then look within the offending circuit for the problem.


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gunns

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Posted: 05/16/12 04:05pm Link  |  Quote  |  Print  |  Notify Moderator

Fire Instructor wrote:

Dave - Sparky is right on the money with his advice. Try to isolate, then look within the offending circuit for the problem.


Problem is "all" the circuits are affected.

smkettner

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Posted: 05/16/12 04:12pm Link  |  Quote  |  Print  |  Notify Moderator

Now repete the process with the branch neutrals also disconnected except the one test circuit.
Going to be a bit tedious. Start with water heater, converter, fridge circuits.
Otherwise next will be pulling the grounds also to narrow it to one circuit
At least you know it is not the cord.

Any appliances you can unplug... do it. Fridge, microwave...


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Gdetrailer

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Posted: 05/16/12 04:15pm Link  |  Quote  |  Print  |  Notify Moderator

Dave-Sparky writes "I will have to disagree with the above statement regarding using the breakers. If you have turned off all the breakers, then there is no source for the current to be leaked from the neutral to ground."

OK, well say that you do have some minor leakage between neutral-ground on one of the circuits.

Having all the neutrals tied together WILL trip the GFCI.

How can this happen even after turning off the breakers you ask?

Simple, electricity will seek the path of least resistance and since all the neutrals are tied to the neutral buss you will affect EVERY branch circuit in the breaker box.

Removing all the Hot AND neutrals will allow to isolate each and every circuit until you find the offending one.

Doesn't matter if you turn off one or all breakers, it only will take ONE breaker turned on to trip and it doesn't have to be the circuit which the power is applied (remember all the neutrals are tied together).

mexbungalows writes "Hmm, would it not be easier to branch protect the circuit being used inside the RV? I seem to recall five decades of RV'ing without benefit of GFCI protection."

RVs do use individual branch protection, the problem stems from requirements for HOMES to have GFCI protection on ALL outlets which may have potential for being used near water.

The problem though when connecting a RV to a home branch which has GFCI you are now adding a large potential for false trips. Basically you are expanding the existing branch and adding a breaker box plus additional GFCIs.

Ideally (and this is what I did) you can have a 120V 30A RV outlet installed and plug your RV into that, no more false trips since the 120V 30A RV outlet is not required to have GFCI.

"First it would be helpful to understand why GFCI protection is important and what it does for a living."

GFCIs detect an imbalance of current between Hot and Neutral, basically monitors how much current is on the Hot and if the neutral current is not the same it will cut power to the Hot.

The idea is if YOU become part of the current return (IE you are a return path to ground and are being electrocuted) then you will reduce the amount of current on the neutral. When this happens then the GFCI will detect and cut power SAVING your life. The trip point used to be 10 ma but if I remember correctly that has bee reduced to 5-6ma and the GFCI must trip.

"Secondly, where GFCI protection would be moot or inappropriate."

Generally you can count on GFCIs on kitchen, bath, basement, outside and garage outlets.

In older homes it is not required to add GFCI unless you remodel (grandfathered) but I do feel they are something to consider since they CAN save your life.

gunns

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Posted: 05/16/12 04:40pm Link  |  Quote  |  Print  |  Notify Moderator

Gdetrailer wrote:

Dave-Sparky writes "I will have to disagree with the above statement regarding using the breakers. If you have turned off all the breakers, then there is no source for the current to be leaked from the neutral to ground."

OK, well say that you do have some minor leakage between neutral-ground on one of the circuits.

Having all the neutrals tied together WILL trip the GFCI.

How can this happen even after turning off the breakers you ask?

Simple, electricity will seek the path of least resistance and since all the neutrals are tied to the neutral buss you will affect EVERY branch circuit in the breaker box.

Removing all the Hot AND neutrals will allow to isolate each and every circuit until you find the offending one.

Doesn't matter if you turn off one or all breakers, it only will take ONE breaker turned on to trip and it doesn't have to be the circuit which the power is applied (remember all the neutrals are tied together).

mexbungalows writes "Hmm, would it not be easier to branch protect the circuit being used inside the RV? I seem to recall five decades of RV'ing without benefit of GFCI protection."

RVs do use individual branch protection, the problem stems from requirements for HOMES to have GFCI protection on ALL outlets which may have potential for being used near water.

The problem though when connecting a RV to a home branch which has GFCI you are now adding a large potential for false trips. Basically you are expanding the existing branch and adding a breaker box plus additional GFCIs.

Ideally (and this is what I did) you can have a 120V 30A RV outlet installed and plug your RV into that, no more false trips since the 120V 30A RV outlet is not required to have GFCI.



Are you saying that you think that the doubled GFI hookup is causing a false trip and I should just put in a designated RV outlet?




"First it would be helpful to understand why GFCI protection is important and what it does for a living."

GFCIs detect an imbalance of current between Hot and Neutral, basically monitors how much current is on the Hot and if the neutral current is not the same it will cut power to the Hot.

The idea is if YOU become part of the current return (IE you are a return path to ground and are being electrocuted) then you will reduce the amount of current on the neutral. When this happens then the GFCI will detect and cut power SAVING your life. The trip point used to be 10 ma but if I remember correctly that has bee reduced to 5-6ma and the GFCI must trip.

"Secondly, where GFCI protection would be moot or inappropriate."

Generally you can count on GFCIs on kitchen, bath, basement, outside and garage outlets.

In older homes it is not required to add GFCI unless you remodel (grandfathered) but I do feel they are something to consider since they CAN save your life.


* This post was edited 05/16/12 04:52pm by gunns *

smkettner

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Posted: 05/16/12 04:53pm Link  |  Quote  |  Print  |  Notify Moderator

I don't think the serial GFIs are causing the trouble.
I think it is the water heater, fridge or converter.
Consider unplugging or disconnecting these three at the appliance and recheck.

Wayne Dohnal

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Posted: 05/16/12 06:14pm Link  |  Quote  |  Print  |  Notify Moderator

I highly recommend this post for troubleshooting GFCI trips:

GFCI troubleshooting post


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Posted: 05/16/12 07:00pm Link  |  Quote  |  Print  |  Notify Moderator

The NEC requires RVs to be treated as secondary panels. Meaning the neutral and ground leads are to be isolated. I've found instances where the ground lead was contacting the neutral lead on a outlet, thus causing the source GFI to trip. By removing a neutral from the buss bar, one at a time the offending circuit was isolated and the bond between neutral and ground was located and corrected. Could be time a consuming job.

Richard

Gdetrailer

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Posted: 05/16/12 07:34pm Link  |  Quote  |  Print  |  Notify Moderator

gunns writes "Are you saying that you think that the doubled GFI hookup is causing a false trip and I should just put in a designated RV outlet?"

No, but some GFCIs tend to be false tripped when presented with additional GFCIs downstream.

To make matters worse, your RV presents an additional problem with the earth grounding.

In your home system there is to be only ONE grounding point which is in the main breaker panel. That is where the neutral is "bonded" to the earth ground via the grounding stakes.

Your RV must have the safety ground bonded (green or bare wire) to the metal frame, depending on the surface ground conditions (IE wet rainy days) your RV frame can be temporarily "grounded" via jacks or stabilizers. This causes what is known as a ground loop which can "confuse" the GFCI upstream (the home outlet protected by a GFCI)causing false trips but I don't think that is the issue at hand with the OP.

This was one of the problems I had when I plugged my RV into a porch outlet, never tripped when the ground was dry but after a good heavy soaking rain I would have to reset the GFCI.

I installed a dedicated 120V 30A RV outlet which stops the false trips.

On edit.. In theory and on paper it should be fine with GFCIs in serial and the fact that the OP did not have any problems with tripping I don't think the issue is with the GFCIs but in the RV.

Something HAS changed to cause this.

The two items which tend to cause these issues the most with GFCIs is the water heater electric element burning out and the fridge electric heater shorting to the case.

The fridge generally will be plugged into an outlet (which often is not GFCI protected), it can be found by removing the outside access panel and should be located near the panel. Unplug the fridge then check to see if the GFCI trips.

The water heater element most likely will be hard wired and you would need to determine which romex cable it is and disconnect the Hot and neutral.

In some cases the converter actually had some leakage from the neutral to ground.

The only way to find the problem IS to completely isolate the Hot AND neutral for each circuit.

* This post was edited 05/16/12 08:06pm by Gdetrailer *

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