Can I run my Onan while plugged into shore power?

mrad wrote:
Thanks. If I am starting it weekly to keep gas running through it, is it best to unplug it? Can I start it while plugged in then unplug it?

Unless you have a particular concern about burning the gas in it, doing it every week is probably overkill. Exercising less frequently may make it less onerous to unplug or turn off the shore power each time.

Onan themselves recommend a 4 week schedule:

To prevent such problems, it is recommended to run gasoline generators at a minimum of 50 percent capacity (2000-watts, or one air conditioner for a 4000-watt set) for two hours once every four weeks. This is necessary to help keep moving parts lubricated, expel moisture and control fuel varnishing in the carburetor. A long two-hour exercise period is preferable to several short periods

One of the first things the dealer told me was to unplug before starting genset. Technically the transfer switch should allow you to remain plugged in however, the transfer switch is a mechanical device that can an does fail.
There is simply no reason to remain plugged in, no reason to take a chance.
Unplugging is easy enough to do. Unplugging makes it 100% foolproof vs. hoping everything works as designed.

Yes. It will default to generator power if the generator is running. That is the job of the transfer switch.

I have run my 5500 Onan while plugged in. It switches to generator power - I did it simply to exercise the genny while I was campground hosting for 3 months. I think I did have an issue with the genny hour meter though. I think it continued to run after shutting down the generator - somehow being energized from the shore power. My hour meter went from 4XX hours to over 2000 this winter and I never used it except to exercise it monthly while plugged in.

Bionic Man wrote:

dedmiston wrote:
Yes and no.

You can run it, but it won't actually exercise it since there won't be any load.

You're better off disconnecting from shore power first.

Maybe some are set up that way, but mine isn't. If I have my 5er plugged into shore power and the generator running, the generator is the default source of power.


That said, there is no reason to have the trailer plugged in when the generator is running.

My C too

Assuming you have a working automatic transfer switch, then yes.

Don't take a chance on back-feeding. Unplug your rig then start genset.

dedmiston wrote:
Yes and no.

You can run it, but it won't actually exercise it since there won't be any load.

You're better off disconnecting from shore power first.

Maybe some are set up that way, but mine isn't. If I have my 5er plugged into shore power and the generator running, the generator is the default source of power.

That said, there is no reason to have the trailer plugged in when the generator is running.

Power should default to the generator while plugged in but to be on the safe side, I would secure the shore power

dedmiston wrote:
Yes and no.

You can run it, but it won't actually exercise it since there won't be any load.

You're better off disconnecting from shore power first.

Thanks. If I am starting it weekly to keep gas running through it, is it best to unplug it? Can I start it while plugged in then unplug it?