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For the electrical gurus. Getting 50 Amp off two outlets?

ov10mech
Explorer
Explorer
I am considering buying a 5th wheel that has two air conditioning units with 50 amp service. The location where it will be placed permanently only has 30 AMP service, so I will not be able to run both at once. However, there is a standard outlet about 20 feet away from the camper that could technically give me the juice needed to un that 2nd AC when I need to. The question is - is it possible to somehow combine these two power sources into a single 50 AMP input? Its a bit easier on a boat because there are two separate input plugs.
33 REPLIES 33

MEXICOWANDERER
Explorer
Explorer
Senor Hoosier Cruiser,

What is the value of your unloaded voltage?
Starting voltage?
2 heat pumps in operation?
One heat pump running, the second heat pump starting?

Hoosier_Cruiser
Explorer
Explorer
My motor home has two heat pump air conditioners. After setup and allowing for the batteries to top off charge, the total load when running both air conditioners is 24 amps. I could only run one with the non-heat pump air conditioners. When the residential frig starts, I see a momentary peak at 29 amps and then settles down to 26 amps. I turn off one air conditioner to run microwave or other major appliance.
Hoosier Cruiser

AllegroD
Nomad
Nomad
Lantley wrote:
time2roll wrote:
I read plenty of posts where 30 amp will run two air conditioners.
Try once and see. Watch your voltage, especially on the hot days.

In the end the correct answer is maybe?


The answer is maybe. It depends on the wiring. Are you coming off a CG line that is overloaded. If you try it, get a PI EMS which cuts your power if volts drop to 104 so you do not end up with heat damage on your AC or other electric items.

I like the idea posted earlier of, instead of adding another 30 amp, upgrade to an RV 50 Amp.

bob_nestor
Explorer III
Explorer III
This thread has been entertaining to say the least. ๐Ÿ™‚

I had two initial thoughts about this when I first read the original post.

1) I'm always amused by all the people afraid of propane and wanting an all electric RV. I recall the long running argument George Westinghouse and Thomas Edison had over DC vs AC and some of the shenanigans they pulled trying to scare people onto their side of the argument. There are still people today, generations later, who have fears over electricity that are rooted in those arguments. Obviously those arguments don't scare the OP which is good!

2) If you have to ask if something can be done because it's not an off-the-shelf commodity, then it's probably something you don't want to do.

And for what it's worth, I'm an EE although my career was spent working in computer engineering, not power. I know just enough to wire things up correctly at the house and in my RV, and some might debate how good that knowledge really is. Unless I knew I was pulling power from two different legs I doubt I'd try this, but I don't have to since I ran 220v/50a to my RV garage.

wnjj
Explorer II
Explorer II
ScottG wrote:
I'm not going to be goaded into arguing with you or anyone else regardless of your attempt at insulting me. By your tone I can tell that if I were to explain every point it would just degrade into more argument.

Honestly, no insult was intended and I'm sorry if you took it that way. I just happen to agree with the guy who posted a concern about when things go awry. As an EE for over 25 years I stand by my opinion that "just works" isn't sage advice for things electrical, generally speaking.

Lantley
Nomad
Nomad
time2roll wrote:
I read plenty of posts where 30 amp will run two air conditioners.
Try once and see. Watch your voltage, especially on the hot days.

In the end the correct answer is maybe?
19'Duramax w/hips, 2022 Alliance Paradigm 390MP >BD3,r,22" Blackstone
r,RV760 w/BC20,Glow Steps, Enduraplas25,Pedego
BakFlip,RVLock,Prog.50A surge ,Hughes autoformer
Porta Bote 8.0 Nissan, Sailun S637

time2roll
Nomad
Nomad
I read plenty of posts where 30 amp will run two air conditioners.
Try once and see. Watch your voltage, especially on the hot days.

Captain_Happy
Explorer
Explorer
Question: Does your RV site have a power pedestal with a Electrical Meter in it? If it does why not just change out the 30 Amp 120 volt receptacle to a 50 amp receptacle fed by 1 50 amp 2 pole breaker.

And the answer to your question will a 30 amp service be able to run 2 A/C units, the answer is NO.

ov10mech
Explorer
Explorer
Thanks for all the informative replies. I think I am leaning towards adding a second 30 AMP shore power receptacle and running the 2nd AC off that. Does anyone know if two ACs will run on a 30A service if no other appliances or water heater are running? I dont expect to run these all the time, just on hot days where one might not be able to keep up.

Lantley
Nomad
Nomad
This is what you need RV Safepower transfer switch.
THe device is designed to do exactly what you want. It is designed to work on GFI outlets. I have one and it works great

19'Duramax w/hips, 2022 Alliance Paradigm 390MP >BD3,r,22" Blackstone
r,RV760 w/BC20,Glow Steps, Enduraplas25,Pedego
BakFlip,RVLock,Prog.50A surge ,Hughes autoformer
Porta Bote 8.0 Nissan, Sailun S637

Bill_Satellite
Explorer II
Explorer II
SoundGuy wrote:
Bill.Satellite wrote:
The combiners do work but please understand that 50amp services provides you with 5 separate 50 amp legs or a total of 100 amps of service.


Surely a typo - you must mean "2 separate 50 amps legs".


Oops, thanks, I will fix that!
What I post is my 2 cents and nothing more. Please don't read anything into my post that's not there. If you disagree, that's OK.
Can't we all just get along?

MEXICOWANDERER
Explorer
Explorer
Isn't learning part of the enjoyment of having a forum discussion? Perscuse me, a polite discussion?

ScottG
Nomad
Nomad
wnjj wrote:
ScottG wrote:
To the OP, as usual, a conversation regarding electrical questions has been taken down a long path with many detours and there are many wrong statements and frankly bizarre theory's bouncing around that's it's just not worth reading anymore.

Bottom line is just try it.
If it works, it works. if it doesn't, it doesn't (probably because of a GFCI).
As a career EE I can tell you there will be no harm either way.


As a career EE, you should know that "if it works, it works" is bad advice. Working and working safely are too different things entirely. You didn't address the legitimate open neutral concern.


I'm not going to be goaded into arguing with you or anyone else regardless of your attempt at insulting me. By your tone I can tell that if I were to explain every point it would just degrade into more argument.

MEXICOWANDERER
Explorer
Explorer
Charlie Chan say...

"Sometime long tortuous path better way than..

short easy path over cliff".