Help! Generator and Shore power AC breakers tripping under load

[AZ Parothead]

Hi All,

Totally bumfuzzled here in Fajardo. I am having an AC system problem. Onboard I have an northern lights Jennie and a dual 30/120 shore power setup.

When I hook up the shore power, the shore power available light on the AC panel lights up indicating power avail. However, as soon as I try any load, the breaker at the power cord (EFCI) trips.

Ditto with the generator. As soon as any load is placed on the circuit the EFCI for the generator pops.

To me, that means that that the problem must be downstream of those 2 breakers since the same problem happens with different sources.

Hours of research online seems to suggest this might be a ground/neutral fault in the panel but I have no idea how to find and troubleshoot.

Can someone please point me in a troubleshooting direction??

THANKS!

[topmast]

Is this an existing system that has recently failed or new wiring?

[Dsanduril]

Open (turn off) every breaker on the AC panel. Pull the plug on every AC connected device. Turn on the AC (either Gen or shore). Sounds like at this point you get "AC Available" light? Close one breaker. EFCI trip? If not, try to run whatever is connected to that breaker. If it doesn't trip re-open breaker and wash/rinse/repeat with each breaker one at a time.

If you've already gone that far and have trips with more than one load then it has to be in the common neutral wiring. EFCI is expecting the same current in the hot and neutral legs. If it doesn't see it then some current must be going elsewhere. Working from the point where the shore power and gen power cables meet, check the neutral and all connections from there to the AC panel. Likely one is somehow broken/damaged.

[AZ Parothead]

Originally Posted by topmast

Is this an existing system that has recently failed or new wiring?

Existing. No changes to wiring.

[AZ Parothead]

Originally Posted by Dsanduril

Open (turn off) every breaker on the AC panel. Pull the plug on every AC connected device. Turn on the AC (either Gen or shore). Sounds like at this point you get "AC Available" light? Close one breaker. EFCI trip? If not, try to run whatever is connected to that breaker. If it doesn't trip re-open breaker and wash/rinse/repeat with each breaker one at a time.

If you've already gone that far and have trips with more than one load then it has to be in the common neutral wiring. EFCI is expecting the same current in the hot and neutral legs. If it doesn't see it then some current must be going elsewhere. Working from the point where the shore power and gen power cables meet, check the neutral and all connections from there to the AC panel. Likely one is somehow broken/damaged.

Thanks! I’ve already tried your first suggestion so I’m on to the second. Will report back.

[GuerrillaCamper]

Um... have tried replacing the gfci breaker? They do go bad. Think of them as the old distributor caps found on older British sports cars. Don't get them wet; damp doesn't work too well either.
I get many calls in a week of customers complaining of the gfci/arc fault combo breakers tripping with little to no provocation. I generally suggest replacing with an arc fault only breaker and a new gfci receptacle. Don't know the code requirements in your jurisdiction, but eliminating as many gfci trip points is a good place to start. Arc fault good! Ground fault bad.

[BruceS]

I had a very similar problem on my houseboat.
The combo inverter/charger sees both shore & Genny power as AC power so when it was installed initially both were fed through contactors that have a lockout bit mounted between them so only one or the other can be engaged at any time.
One contactor failed & wouldn't drop out due to a loose/dirty wire connection.
More over heating caused further damage and on it goes.
Good luck chasing it!