Generator circuit breaker, maybe?

[madgoan]

Hi Folks,
First off, Im an idiot when it comes to electrical, also color blind.

I have a Onan Marquis 7000 generator in my class A gas unit. It has two 30 amp breakers.

I went to run the generator just to excercise it. I opted to start it from the outside start switch on the generator. When I removed the cover to get to that switch, I noticed on of the two breakers was in 'off' position. That was odd to me.
When I moved the switch to on position a loud hum started. I did turn the switch back off.
This was while the generator is NOT running. I am plugged into shore power.
I also noticed I have power at the breakers when the generator is NOT running (but plugged into shore power). Is this correct?

Everything in the RV is working fine.
I did install a Residential fridge but did no electrical work except to mpve the electric outlet a few inches over.

Is it possible I just have a bad circuit breaker?
A bad xfer box?

Thoughts on how to proceed and what to check are appreciated!

Thank You!

[avfordguy]

Possible transfer switch is stuck back feeding genset

[twinboat]

Open up the Auto Transfer switch and check all of the wiring. Could have a burt wire laying against another shorting things out.

[THenne1713]

YES, TRANSFER SWITCH should be wired to prevent shore power from connecting w/ GEN; either a short or miswired?

[shootist]

Your transfer switch stuck it sounds like, not disconnecting one leg of the gen.

[Archer2]

I’m going to go with everybody else who suggested a transfer switch problem backfeeding the shore current into the generator windings on one leg of the generator output. If the generator is not running then the windings look like close to a dead short to any external voltage source and would trip the breaker.
It would also mean that with the generator running you could have 120VAC present at the bare shore power plug-very dangerous!

[madgoan]

I think you all are correct on the Auto Transfer switch.
I swapped circuit breakers yesterday, the problem followed the wires.
The Xfer switch seems to be totally dead now.
We have disconnected from shore power and trying to get someone out to replace the xfer switch.
I looked at the wiring in there and I think it may be beyond me to do this myself. I will look at it a bit more.
Still have to track down a new xfer switch.

Thanks for the good input!!!!!

[madgoan]

Sure there is already a thread on this:
What 50amp Xfer switch would you recommend?

Thanks again!

[madgoan]

I went ahead and pulled the Xfer switch. Sure enough melted and fried!
Wired us to direct shore power for now. Researching new Xfer switch.