RV Breakers Trip on Shore Power but not Generator

[tcrespo]

Hi All - new to the forum (and to RV life) - just picked up a used Class A with a 50 Amp circuit and an Onan Marquis Gold 5500 Generator.

Had an electrician install a 30 AMP dedicated circuit in the garage and I'm using a dongle to convert from the 30 AMP outlet to the 50 AMP plug on the RV.

If I run the generator, everything works fine in the RV. When I plug into my shore power, nothing works correctly and in fact, my lighting circuit breaker trips. All of the other devices do not turn on (AC, etc).

I should add that the house breaker never trips.

I have full confidence in my electrician and thought I'd seek out some advice here. I am using the extension that came with the RV (looks like a 25 foot 50 AMP cord). Can't get the RV close enough to the house to eliminate that as a potential failure point.

Thoughts (and thanks in advance)?

Tom

[tcrespo]

wnjj wrote:
No reason to order a new multimeter. Just touch the leads together when on the lowest ohm setting and see if it reads near 0.

Does the breaker trip with just the extension cord plugged in or does it need to be connected to the RV also?

Poor grammar on my part - I updated it to say that I'm going to replace the extension cord as it's pretty old and I don't trust it. Thanks for the catch!

[wnjj]

No reason to order a new multimeter. Just touch the leads together when on the lowest ohm setting and see if it reads near 0.

Does the breaker trip with just the extension cord plugged in or does it need to be connected to the RV also?

[tcrespo]

I confirmed while the electrician was here that it's a 120V circuit - saw him put his meter on it when he was finished to confirm.

The coach is new to me, so I'm still learning about how everything is setup, but from what I see, the shore power cord is plugged into a 50 Amp receptacle in the storage compartment. To hook up to the generator, I'm in that plug; To go to shore power, I pull that plug and hook it up to the new outlet.

Note: The sticker inside of my electrical area says that the coach can run on 30 Amp or 50 Amp, 120V or 240V.

I did some final confirmation this morning in multiple combinations, just to be sure. Shore power to adapter; Shore power to power surge to adapter; shore power to extension to power surge to adapter; Basically tried all combinations and the only one that will not work correctly is when I use the extension cord.

I put a multimeter on it to check for shorts, but none are present. The cable is pretty old so I'm going to order a new one just in case.

In the end, I'm currently hooked up shore power cord to surge protector, and then to a dongle (50 A to 30 A) and everything is humming along nicely.

Tom

[wolfe10]

Strong suggestion, do NOT plug into that shore power outlet until you have tested it. 30 AMP RV is 120 VAC. Many house type 30 AMP outlets are 240 VAC.

Said another way, the correct wiring is:

ONE hot
one neutral
one ground

See picture above.

[CA_Traveler]

Are you saying that the 25' extension is a 30A or 50A extension cord? A short would cause the house CB to trip, but it could be miswired.

How is the gen connected and what is a Coach receptace? I would expect the gen to be hard wired to a transfer switch.

PER ABOVE: Make sure the 30A plug is wired for 120V. Just so you know your first post does suggest it could be wired for 240V.

[tcrespo]

I figured it out. When I was testing the generator, it was the plug straight to the Coach receptacle. When I tested to the house, I had to use the 25’ extension.

I moved the RV as close to the house as possible so that the cord would reach - it works fine. Haven’t tested with a meter yet, but I’m guessing that cord has a short.

Appreciate the advice - have a great one!

[BB_TX]

If you have a voltmeter measure across rectangular pins on your 30 amp outlet he installed. (Round is ground) If you measure 240 vac you need to call him back to correct it. And hope nothing is fried.

[opnspaces]

Well,,,,,,,hate to say it but your electrician might have just cost you hundreds or thousands of dollars in electrical repairs. Right now you should call your electrician and have him verify that he put in a 30 amp 120v RV circuit and not a 30 amp 240 volt electric dryer circuit.

120 volt RV circuit is okay.

240 volt Dryer circuit potentially just burned up a bunch of electronics in your RV.

Electrician should be able to say he wired it Hot Neutral and Ground.

If he wired it Hot Hot Neutral you have a problem.