tripping gfci breaker on 30 amp supply post

[Kevin Brooks]

Hello, my name is Kevin, I have a 1984 Beaver Regency 38. We bought this a little over a year ago and have put about 7,000 miles on it since then, we have been to many camp sites and have had no problems until this last week end we took a short trip close by our home to a state park. I plugged into a 30 amp post that had gfci breakers and immediately tripped the breaker, I turned all my breakers of in the rv and reset the breaker on the post, it stayed on. I turned my main breakers on in the rv and the post breaker still remained on, when I would turn on any of my ac, heater, refig, it would trip the gfci. I have checked all my receptacles for proper wiring, and have checked my breaker box to make sure I had a ground tie bar and a neutral tie bar and that there was no mixing, or that there was none tied together.
I have been told by some that older ac units or any kind of older appliance can cause a gfci breaker to trip, if this is true is there a work around for this, or is there something else that I should be looking for.

[David T. Richelderfer]

The water heater and battery charging would use most of the 30 amps available.  My electric water heater uses some 17 amps alone.  When I first plug in my inverter's battery charger will pull over 10 amps until it goes off fast charge.  My air conditioners each will pull 15 or more amps.  My fridge pulls 3.5 amps when on AC power.  My convection/microwave oven pulls over 15 amps.  Then there's the TVs and lights.  Almost any combination of these power hungry devices will max out a 30 amp power source.  Also, it may be the power pedestal's GFI has been tripped numerous times and has become weak.

Did you try turning on your coach's breakers one-at-a-time, then go look at how much power is being pulled?  The power demand just cannot exceed about 30 amps.

[Kevin Brooks]

thank you for your response, at the time i was tripping the breaker i had nothing on except the frig, I don't believe my problem is that i am drawing too much current. My understanding of gfci, and I am by no means an electrician, is that it is measuring current leakage to ground thru the neutral return line and that if there is as little as 5 ma loss it will cause the gfci breaker to trip.
 I did start to try to trip the breakers one at a time but i was on limited time and walking back and forth to the post ate most of that time up so i had to just close shop and go home, I do know the ac turning the ac breaker on, with ac off, would trip the gfci breaker on the post.

[Edward Buker]

Kevin,

This is a very difficult problem to diagnose given the minute amount of current that is required to cause a GFCI fault and the almost immediate response time these devices are required to meet when using that type breaker.

Did you try another campsite? I ask that because almost any coach current using device, tried one by one caused tripping, yet the main breaker circuit, ground and neutral buss alone was OK meaning your stray current is not a fault of the coaches basic wiring of the panel, transfer switches, and power cord.

When you add single circuits loads, one by one, and all cause tripping that indicates that any load in the coach would cause the problem. The GFCI looks at the hot line and the neutral line for current in and out returning differences. If they are 5MA apart it shuts down.

All you can do is tighten all you current path connections (panel breaker, hot, and neutral connections on all circuits and main, clean transfer switch contacts and tighten lugs. Burnish the main plugs leads on your post plug with fine sandpaper, basically assure all tight connections so the paths are all good. To let you know the difficulty here you can have a spike come in the hot line and have a surge protector in the coach pass it to ground and that imbalance can trip a GFCI breaker. You do what you can do to assure good wiring and then scratch your head on these...

Later Ed

[Gerald Farris]

Kevin,
I think that you are fighting as loosing battle here as my 2000 Marquis will also trip a GFCI, and I have never been able to correct it. Fortunately, there are virtually no RV parks that use GFCI breakers on the 30 or 50 amp outlets. However,
I ran into a Provincial Park in Newfoundland last summer that had a GFCI breaker on all outlets, even the 50 amp one. Therefore, I dry camped for that stay, but the 2004 and 2005 Beavers that I was traveling with had not problem.

Gerald 

 

[Kevin Brooks]

thank you all for your response, Ed i did check my cables when i was at the camp site and did find some charring, i did not have any enory or sand paper so i scraped them the best i could with a knife but even with them clean i would imagine the heat created to char them would be enough to cause the female receptacle to swell so that the connection would be questionable. So I think for now the best thing for me to do is replace my power supply cord and not worry so much about the gfci for now since it seems camp grounds are few and far between that even have a gfci on 30 and 50 amp post

[Edward Buker]

Kevin,

If you get heating or charring you have a problem that needs correction. You may be able to trim off some cable and use a commercially available plug. If you can get a waterproof version then great, it is not one that is waterproof you can use Lexol to take care of any gaps. These sit under covers when plugged in so they remain relatively dry.

If you prefer to change the cable out with one with a molded plug just be sure you can find one with the same gauge wire. The molded plug version is likely to be more water proof.

Later Ed