Generator/Shore Power Question

GD350M

Senior Member
Joined
Jul 31, 2013
Messages
445
Location
Lafayette, LA
Good Morning All,

We are about to embark on your trip to FL and I will be running the generator to keep the camper cool while traveling. My question to any one of you that can answer is this.

When we did the PDI, the guy told us that we could not turn the breakers on to the generator as long as we were connected to shore power. So thats what we have been doing. But I have been confused about the way this operation goes. So I have shore power coming in to a transfer switch and I have the generator coming into the other side of the transfer switch. When I crank the generator (no shore power connected to the unit) the generator starts and about 20 seconds later the transfer switch kicks over to generator side and I have power.

What I would like to know is can my breakers be on all the time on the generator and while I am hooked to shore power and start the generator before we leave, would this keep the generator from suppling power to the camper and then vise versa where if we were on generator power and I connected to shore power, will the unit automatically switch to shore power?

Why I ask is because it seems a little ridiculous that I have a start button for the generator in the camper, but then I would still have to go to the generator to switch the breakers on? Why put a switch in the camper if I have to go to the generator, I could just start it there?

Thanks for any feedback and I hope the post isn't to confusing.
 
There is nothing wrong with keeping the breakers in the "ON" position in the generator cover. I would not recommend starting the generator while shore power is ON and under load. This may cause an issue when the transfer switch switches. The transfer switch gives priority to the generator, meaning that even if there is shore power, if the generator starts, it will switch all coach power over to the generator.
 
I dont have access to the drawings to be 100% sure they didnt do something stupid but by design you should be able to have shore power connected and the generator breakers closed. Everything is supposed to be controlled by the auto transfer switch. It senses when shore power drops below 15% nominal voltage, opens the transfer switch to neutral, sends a start command to the generator, then 10-30 seconds later transfers to generator power. Then when shore power returns to normal it begins a re-transfer timer (just to keep it from cycling) and once that is done it commands the transfer switch to neutral then to shore power and initiates a cool down timer for 5 mins or so then the generator shuts down. Thats the way its supposed to work but I dont have access to any drawings and dont have your model with a generator so I cant say for sure that its set up correctly.
 
Rob, one point you didn't address, and I would like to hear your answer to, is Stephen wants to have his generator running while he's towing. Will this pose any issue with the fact his trailer is connected to his truck?
 
Rob, one point you didn't address, and I would like to hear your answer to, is Stephen wants to have his generator running while he's towing. Will this pose any issue with the fact his trailer is connected to his truck?

We never had any reason to have the gen running while driving, but we started it all the time when stopping for breaks to w.arm food and such. Stayed all hooked up and everything. We had a different brand toyhauler but dont see why it should make any difference. I have read of alot of people running gen and furnace while driving in the winter
 
We never had any reason to have the gen running while driving, but we started it all the time when stopping for breaks to w.arm food and such. Stayed all hooked up and everything. We had a different brand toyhauler but dont see why it should make any difference. I have read of alot of people running gen and furnace while driving in the winter

That sounds good as I have an on-board generator and wasn't sure if I could do that. I guess I just want to make certain everything like the trailer brakes and lights, etc., will continue to operate correctly from the umbilical cord and nothing will get shut off or disconnected via the automatic transfer switch or anything. I guess all that stuff must bypass the whole trailer power systems.
 
I dont have access to the drawings to be 100% sure they didnt do something stupid but by design you should be able to have shore power connected and the generator breakers closed. Everything is supposed to be controlled by the auto transfer switch. It senses when shore power drops below 15% nominal voltage, opens the transfer switch to neutral, sends a start command to the generator, then 10-30 seconds later transfers to generator power. Then when shore power returns to normal it begins a re-transfer timer (just to keep it from cycling) and once that is done it commands the transfer switch to neutral then to shore power and initiates a cool down timer for 5 mins or so then the generator shuts down. Thats the way its supposed to work but I dont have access to any drawings and dont have your model with a generator so I cant say for sure that its set up correctly.

JustinThyme,

Thank you on this information. So let me understand this, is that I can start my generator right now, turn the (2) 30amp breakers on, power to the camper is running off the generator. I then get to my destination, leaving the generator running on the camper, then plug in the shore power, turn the pedestal breaker on, 30 sec later, the transfer switch switches the camper to shore power and then 5 min later the generator should shut down? Sounds right?


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Stephen, if our RV'S were equipped with a transfer switch like a home backup generator, then that would be true. Unfortunately, our RV'S are not equipped like that. The transfer switch equipped in our RV's is just a simple relay that the coils are powered by the generator side of the relay. On top of that, the generator is controlled manually. Therefore you have to press a button to start or stop the generator. That is unless you have added the automatic remote control module, the EC30-W.
 
Thanks Specularius, as always you have great information for me. I am actually watching a video on YouTube about the EC30-W


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One thing that I discovered while running the generator and traveling down the road. You need to consider the ambient temperature, the engine/exhaust heat from the truck can and will cause the generator to overheat.

Big Mike
 
Stephen, if our RV'S were equipped with a transfer switch like a home backup generator, then that would be true. Unfortunately, our RV'S are not equipped like that. The transfer switch equipped in our RV's is just a simple relay that the coils are powered by the generator side of the relay. On top of that, the generator is controlled manually. Therefore you have to press a button to start or stop the generator. That is unless you have added the automatic remote control module, the EC30-W.

Yep, I just found some drawings on the supplied transfer switch that is called automatic but is merely one step above throwing a handle. Is nothing but a time delay relay that senses generator power. Once the generator starts regardless of whether or not utility is connected it initiates the time delay then transfers to generator. If it was me this would be changed in a heartbeat to a real automatic transfer switch or in the least retrofitted with a control module.
 
.... wants to have his generator running while he's towing. Will this pose any issue with the fact his trailer is connected to his truck?
The trailer towing lights and brakes are a completely separate DC system and has nothing to do with the AC system.

But wouldn't the truck cable connection and the generator both be vying to charge the battery(s) and power the 12VDC system? Possible harm to truck? RV?
 
But wouldn't the truck cable connection and the generator both be vying to charge the battery(s) and power the 12VDC system? Possible harm to truck? RV?

No damage will be done. Just like if you were running your truck with a battery charger connected. Systems run like this all the time with no issue.
 

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