Electrical problem?

[firedoc]

If I plug my 50A mh into a 20 amp supply(via adapters) in the garage to keep battery up and run refrigerator it trips the gfi breaker. If I plug it into a non gfi in the house it works fine. What am I missing?

[Old-Biscuit]

GFCI's do not play well with electric heating elements

[Det57]

I know that with a fridge in a house, you should not plug into a GFI as each time the fridge "kicks on" the GFI senses an issue and trips......Maybe the same is happening with the MH...Just a thought.....

[Sonic]

The GFCI is sensing a current leak to ground which is a dangerous condition. Unless the GFCI is faulty (test this by plugging into another GFCI outlet to see if it trips as well) this indicates an electrical problem in the RV. I would do a hot skin test and if that checks out ok, check all the electrical outlets in your RV to see if you can detect any wiring issues.

[harleyjt]

I had the exact same issue. Never really did figure it out. However, one thing I realized later was that at the time, I was running thru a PI portable surge protector. Not sure if taking it out of the picture would have made any difference or not. I have a feeling it has something to do with the heating elements in the Norcold refer as mentioned above.
jt

[firedoc]

Ok, walk me through a hot skin check please.

[vsheetz]

Originally Posted by firedoc

If I plug my 50A mh into a 20 amp supply(via adapters) in the garage to keep battery up and run refrigerator it trips the gfi breaker. If I plug it into a non gfi in the house it works fine. What am I missing?

RV plugged into a some GFCI outlet is often problematic due to neutral and ground bonding difference from residential. However its strange that it works ok until the RR is activated. Might be interesting to see if the GFCI trips with the RR plugged directly into it.

[Gary RVRoamer]

If I plug it into a non gfi in the house it works fine.

The difference between the GFCI and non-GFCi outlet is simply that the non-GFCI doesn't detect the problem. It didn't go away - it just isn't visible. 30A or 50A park power outlets don't have GFCI protection, so you won't see the problem there either. Everything still works, but there is a potential safety problem and you may experience a shock (or worse) at some point in the future.

What am I missing?

You have a ground fault somewhere in the RV wiring, meaning that current that is supposed to be going from the hot wire to the neutral wire is somehow escaping, either directly into the ground wire or through the coach frame or body into the ground (the coach chassis is connected to the ground wire just for that reason).

There are two fairly common sources of a ground fault in an RV:
1. The AC electric mode heater in an RV fridge sometimes develops enough corrosion to allow a tiny trickle of current to flow to the surrounding metal. Since yours trips when you run the fridge, this one is a likely bet.

2. The converter/charger or inverter/charger can leak current if not wired exactly per factory specs.

Neither of those are likely to cause more than a slight tingle shock, but some of the less common ground faults can be severe or even fatal.

A third possibility is that a circuit was added or changed in the 120v load center (breaker box) and the neutral wire connected to the ground bus instead of the neutral bus, or the neutral & ground buses were cross-connected (aka bonded). That will appear as a ground fault at the shoreline connection.

[MisterT]

OR

your GFCI is simply overly sensitive, just as circuit breakers can sometimes be, and not really holding up to the amps you are asking for... your battery Charger could be using many of the 20amps thru the circuit before the fridge even comes on.
The 'house' circuit may not be as sensitive, it's not a GFCI, and therefore may handle it.


if you have a way to 'turn down' your Charger's amp draw, it may work fine on the GFCI. Our Magnum Inverter remote panel has a 'SHORE' button, which allows you to limit the amount of shore amps the Charger can use, while you are using other items.

[Jim18655]

GFCI receptacles don't measure current like a breaker. They only check that the neutral has the same current returning that the hot supplies. Any more than a 5 mA difference will trip the circuit.

[powercat_ras]

The GFCI trips is there is over a 5 one thousandth of an Amp ( 5 mA ) difference between the HOT current and the NEUTRAL Current. Flip off your breakers in the RV breaker panel one at a time trying to reset GFCI after each breaker flip. Repeat flipping prior breaker back on and flipping the next one until you can reset the GFCI and it does not trop.

Something fed by that breaker is the culprit that has what is called a Ground Fault where the HOT current is going to GROUND instead of Neutral.

Yes, the Hot Water Heater Electric Element is one of the more common culprits, so you might try that breaker protected circuit first.

[twinboat]

You can also get a ground fault if neutral is leaking to ground. If the current has two paths, ground and neutral, some of the current will travel thru the ground and the GFCI will sense the imbalance and trip.

Water heaters will need both the line breaker switched off and the neutral wires removed from the panel or element to see if its causing the problem.

Refrigerators will only need to be unplugged, removing line, neutral and ground conductors.

If you have a surge guard built in before, or into the transfer switch, that may also cause a GFCI trip, while its going thru its testing phase.

[Dennis4809]

Narrow it down by turning off all the breakers in the RV, connect to the gfi and see if it holds. If it does, turn on one breaker at a time to see which causes the gfi to trip. Focus on that line.

Good luck,

[J Birder]

It is very possible that the ground and neutral conductors are tied together in the RV. It's easy to check. Just unplug and see if there is continuity between them. If so, you've found the problem. fixing it may not be quite as easy.

Joel