Is Upgrading a 30 Amp. Circuit to 50 amp Service Viable?

[Barrett-FL]

We just purchased a 1995 Bounder with an Onan 7000 Marquis gas powered generator and the coach has a switch to operate the front or the rear (not both) roof-top A/C units. With a "one-or-the-other switch that would mean even on shore-power one can only operate 1 A/C unit at a time.

When shopping we saw a 1997 model with an Onan 5000 and an inner switch that allowed front, rear or both A/Cs to operate at the same time. It had a 30 Amp system.

Being in Florida our summers get hot and muggy and with the mild winter we had this year it will likely be an extremely hot summer.

As I understand it this limitation is due to having a 30 amp service and in order to run both one would need 50 amp.

Is it even viable to upgrade? If so, what is involved in upgrading the existing 30 amp system to 50?

Thanks for any information.

[Rkesselus]

If you are not knowledgeable with electricity you are going to need an electrician. If you do understand basic electricity here is what you will need to do. You need to isolate one of the AC units. It will be directed to one leg of the new 50 amp service. the other leg of the 50 amp service will connect to the current 30 amp line in the motor home. So basically all you are going to do is isolate one of the AC. It will operate off a 20 amp leg of the 50 amp service and one leg of the generator. The transfer switch is going to be difficult based on the wiring of the 7KW generator.
I am first off surprised that a unit with a 7kw generator is wired 30 amp shore set up. Your are most likely going to have to get a new 50 amp transfer switch then the wiring will be much simpler. The Generator legs will transfer parallel with the new 50 amp wiring. Hook up must be done per diagram of new transfer switch as some models use different switching method. Your current AC transfer switches will be deactivated and one leg will go to the added leg from the new service.

[jcgribks]

Here's how I converted my 1996 Itasca Suncruiser with 30amp over to 50 amp. from an earlier post.

http://www.irv2.com/forums/f84/secon...ml#post1509385

There's also a link to a pdf showing how I wired it.

[Dr4Film]

Here is link to a YouTube Video on how to convert your 30 amp RV coach to 50 amp. It is a four part series so make sure you watch them all.

https://www.youtube.com/watch?annota...&v=iFYapUdEUMc

Dr4Film ----- Richard

[wildtoad]

One thing you might double check. When I owned a 1994 Airstream mh which was 30 amp, it had a 7000 gen. The switch allowed BOTH units to run while on gen but only one at a time on shore power.

[d_elegance]

Okay this all sounds firmilar. I had the same kind of issues. I had a that switch too. I am in the process of installing a new box because the one leg was cut off so there could not be another hot wire connected. I replaced the whole box and am figuring it out.

[d_elegance]

Originally Posted by wildtoad

One thing you might double check. When I owned a 1994 Airstream mh which was 30 amp, it had a 7000 gen. The switch allowed BOTH units to run while on gen but only one at a time on shore power.

I have the same generator in my 1996 Holiday Rambler Endeavor LE. My friend that does electric said that the generator had more than enough power to run both ac units but that the rv was not wired to run both at the same time. We are going to fix that problem by running re-wiring the rv. I wanted to keep it all original but if I can have an upgraded system and run both ac units at the same time then that is what I would like to do. He had mentioned something about the 4 prong plug but I didn't understand what he meant. After seeing some of the pictures on this post I now know what he is talking about.

[DENSHER]

Our previous coach, 95 Holiday Rambler Vacationer was 30 amp shore power and had that front or rear AC selector switch but when generator was started that switch became null in the system and both ACs would operate at same time.

[d_elegance]

Originally Posted by DENSHER

Our previous coach, 95 Holiday Rambler Vacationer was 30 amp shore power and had that front or rear AC selector switch but when generator was started that switch became null in the system and both ACs would operate at same time.

Yeah I am not sure how that switch was supposed to work but it's gone now. All of it was removed when i was trying to troubleshoot the system. I couldn't figure out how it was supposed to operate. If I had a chance to speak to another HR owner that had the same system then I probably could have had an easier time with it. It made no sense to me because the thermostate can control the ac units separately so I'm not sure what the need for the switch was. I guess it had a purpose i just could not get it.

[triplewide]

I added a second AC to a 30 amp service. Now have one 15K and one 11K AC. Instead of converting to 50 amp I installed 2 contactors and a manual switch. The switch selects power for the additional AC from coach distribution panel or a second 20 amp power cord run to the park's power pedestal.


The generator will run both AC's with the switch set to "distribution panel" as long as the microwave is not used and the refrigerator and hot water heater are on gas.

Cost about $250 for material, including 20 amp power cord, no labor.

Have pics if interested.

[d_elegance]

Originally Posted by triplewide

I added a second AC to a 30 amp service. Now have one 15K and one 11K AC. Instead of converting to 50 amp I installed 2 contactors and a manual switch. The switch selects power for the additional AC from coach distribution panel or a second 20 amp power cord run to the park's power pedestal.


The generator will run both AC's with the switch set to "distribution panel" as long as the microwave is not used and the refrigerator and hot water heater are on gas.

Cost about $250 for material, including 20 amp power cord, no labor.

Have pics if interested.

Ok sounds like less work than I had planned. Please send pictures. Thank you.

[triplewide]

Originally Posted by d_elegance

Ok sounds like less work than I had planned. Please send pictures. Thank you.

Ran second ac power wire to load side of both contactors. From line side of one contactor ran wire to new 15 amp breaker in coach 30 amp distribution panel. From line side of other contactor ran 10 guage extension cord to power bay. Installed toggle switch, ran 12 volts to it, one wire to each contactor coil.

Your ac may be 13.5 K BTU and may require a 20 amp breaker, check data plate on ac. I plan to install a 20 amp power receptacle near the existing 30 amp factory one which will allow me to plug the additional circuit in with an extension cord similar to the current 30 amp cord.

I also have a dongle that will split campground 50 amps into one 30 amp and one 20 amp circuit for when the campground does not have a 30 amp and 20 amp receptacle on the pedestal.



I saw a post on another thread where a person did about the same thing I did. Except he did not use contactors, just a switch. A lot simpler and cheaper. If I were to do it over again I might do it that way.

If you prefer, private message me if you have questions, can take more pics if you want them.

[triplewide]

He used a switch something like this:

https://www.amazon.com/Heavy-Duty-To...witch+120+volt

Black and white wires from AC to center terminals, distribution panel wires to one pair of terminals, top or bottom, and shore power wires to the remaining pair.

[Barrett-FL]

Thank you to each who responded.

There's a lot of information that I need to digest.

I may call upon those who offered pics for same.

I'll share what I do when I do it.

Thanks!