Generator or 110?

[BRIANnAngel]

We just purchased a 2006 Keystone Raptor with a Onan 5500 generator. We got home and plugged it in like we have done with our other RVs. We had the 110 plugged in and started the generator and then here's where it all went wrong...we turned on the AC and a horrible sizzling noise came from the wall where there is a little metal box in one of the underneath storage areas. It did fry a fuse as well in the breaker box. QUESTION:Are we supposed to turn one or the other off when running the AC? I know we are going to have to have it looked at because it will not work any longer...sad face...
Thanks

[MrWizard]

typically the generator has (2) circuit breakers and one circuit breaker is wired to feed the A/C when there is NO shore power
normally there is a switch manual or automatic to prevent cross feed
it appears that is not working correctly
when you turned on the A/C the two p120v power sources got connected togther thru the a/c

[fj12ryder]

It shouldn't have been an issue if the Automatic Transfer Switch was working properly. And it doesn't sound like yours was. The sizzling you heard was probably coming from the switch box.

There was a big recall some years back for a certain brand of transfer switches, and it's possible that yours was on the list, but never got changed out.

Best thing to do is to dig out your paperwork and ascertain whether you can start and run the generator if plugged into shore power. Even if it shouldn't hurt anything, it's a bad habit to get into.

I would certainly take it to a knowledgeable shop/individual and have it checked out thoroughly. With any luck the only thing damaged was the switch.

You know what they say: "Stuff happens".

[BRIANnAngel]

2chiefsRus wrote:

BRIANnAngel wrote:

2oldman wrote:
Ok, I'll sucker for this. Why would you start the generator?

Well we have not had a RV that had an on board generator before and quiet honestly...we didn't know you couldn't have both on. Now we know....

so I'm assuming you were just firing up the generator to see if it would run? Or were you trying to get more power because there was a power problem with the shore power?

Yes, we had it hooked up to the house power, then a friend was over to look at it so we turned the generator on to show him how quiet it was...it was fine until we turned the AC on then that's when the noise happened and fuses blew.

[BRIANnAngel]

2chiefsRus wrote:
maybe I'm reading your post wrong. Did you have the 110 cord plugged into your sticks and bricks house or into the generator. If you had it plugged into the sticks and bricks, WHY did you start the generator?

Because we didn't know they both couldn't be on at the same time. Rookie mistake that will cost us. We now know....

[2chiefsRus]

BRIANnAngel wrote:

2oldman wrote:
Ok, I'll sucker for this. Why would you start the generator?

Well we have not had a RV that had an on board generator before and quiet honestly...we didn't know you couldn't have both on. Now we know....

so I'm assuming you were just firing up the generator to see if it would run? Or were you trying to get more power because there was a power problem with the shore power?

[BRIANnAngel]

gbopp wrote:
Your Automatic Transfer Switch should prevent you from drawing power from the generator and shore power at the same time.

However, I always unplug from shore power before starting the generator.

Have your unit checked by an electrician or someone knowledgeable in electrical systems.
Something is definitely wrong.

Thank you very much for answering and not making me feel like a dumb ***. I now know what we did was wrong but for future uses ( once we get it fixed) we will know.

[BRIANnAngel]

2oldman wrote:
Ok, I'll sucker for this. Why would you start the generator?

Well we have not had a RV that had an on board generator before and quiet honestly...we didn't know you couldn't have both on. Now we know....

[1492]

Moved from Forum Technical Support

[naturist]

You are not ever supposed to run the generator while plugged into shore power. There is supposed to be either a transfer switch (manual or automatic) OR you have to unplug the rig and plug it into the generator to prevent both sources from powering the rig at the same time.

I do not know why you would start a generator while on shore power. but if that generator applied power to the lines while on shore power, you almost certainly destroyed the generator. I also do not know why the rig would allow you to do that, unless it was wired incorrectly.

[2chiefsRus]

maybe I'm reading your post wrong. Did you have the 110 cord plugged into your sticks and bricks house or into the generator. If you had it plugged into the sticks and bricks, WHY did you start the generator?

[Crazy_Ray]

do you have ATS????

[gbopp]

Your Automatic Transfer Switch should prevent you from drawing power from the generator and shore power at the same time.

However, I always unplug from shore power before starting the generator.

Have your unit checked by an electrician or someone knowledgeable in electrical systems.
Something is definitely wrong.

[2oldman]

Ok, I'll sucker for this. Why would you start the generator?